Potential Sources of Indoor Air Pollution
Market Analysis and LiteratureReview

 

The report summarizes available in-formation on candles and incense aspotential sources of indoor air pollution.It covers market information and a re-view of the scientific literature. Themarket information collected focuseson production and sales data, typicaluses in the U.S., and data on the sourcesand quantities of imported products. Theestimated total sales of candles in 1999varied between $968 million and $2.3billion, while imports were $486 million.The U.S. imports and exports of incensein 1999 were $12.4 and 4.6 million, re-spectively. The scientific literature re-view gathered information regarding theemission of various contaminants gen-erated when burning candles and in-cense, as well as the potential healtheffects associated with exposure tothese contaminants. Burning candlesand incense can be sources of particu-late matter. Burning candles with lead-core wicks may result in indoor airconcentration of lead above EPA-rec-ommended thresholds. Exposure to in-cense smoke has been linked withseveral illnesses, and certain brands ofincense also contain chemicals sus-pected of causing skin irritation.This Project Summary was developedby the National Risk Management Re-search Laboratory’s Air Pollution Pre-vention and Control Division, ResearchTriangle Park, NC, to announce key find-ings of the research project that is fullydocumented in a separate report of thesame title (see Project Report orderinginformation at back).

Background and Approach The potential indoor air impacts of burn-ing candles and incense have drawn in-creased attention in recent years. Thereare three particular areas of concern.Candles with lead-core wicks have beenfound on the market and have beenshown to be a source of airborne leadwhen burned. Metal cores are used tostiffen wicks so they will not fall over andextinguish themselves as the surround-ing wax melts. Lead was commonly usedas a core material until 1974 when theU.S. candle manufacturing industry vol-untarily agreed to discontinue use of leadin wicks. However, candles with leadwicks have been found on the market byan academic as well as a consumer pro-tection group study. Most of the candlesfound that contained lead wicks were imported. Secondly, under imperfect combustionconditions, candles emit soot and cancause property damage by blackeningwalls, ceilings, and carpets. There havebeen an increasing number of complaints regarding black soot deposition in homesin the last decade. Candles are one source of soot. With candles, sooting occurs as a result of incomplete combustion. Candle composition, wick length, anddrafty conditions can all affect candle com-bustion. The amount of soot producedcan vary greatly depending on the type ofcandle. One type of candle can produceas much as 100 times more soot than another.Thirdly, incense smoke can be a major source of particulate emissions in indoor air.

The particulates produced when burn-ing incense can deposit in the respiratorytract. These emissions may contain con-taminants that can cause a variety ofhealth effects, including mutagenic effectsand airborne dermatitis.EPA is currently testing emissions fromcandles and incense to generate data.To support this effort, the report collectsand presents two types of data: (1) mar-ket information, and (2) literature on thepotential impacts of burning candles andincense on indoor air quality.The market information collected fo-cuses on production and sales data, typi-cal uses in the U.S., and data on thesources and quantities of imported prod-ucts. In addition, the report summarizesthe results of a scientific literature review.It reports the findings in the scientific lit-erature regarding the emission rates ofthe various contaminants generated whenburning candles and incense, as well asthe potential health effects associated withexposure to these contaminants.Market InformationPublicly available sources of data,mostly from the U.S. Bureau of the Census, as well as private market studiesand trade literature were consulted to pro-duce this summary of economic informa-tion regarding the candle and incensemarkets. Dialog Information Service and Internet searches were performed to iden-tify market and related information.

TheU.S. Bureau of Census was contacted toobtain import and export data. The Na-tional Candle Association was contacted to obtain industry data.The Census Bureau reports 107 manu-facturing establishments; however, indus-try estimates range from 160 to over 200 manufacturers. Many manufacturers are very small. Candle sales have been grow-ing rapidly in the last 10 years (10 to 15% per year), fueled by consumer interest in aromatherapy and increased demand for home fragrance products in general.There is a wide range in estimates of candle sales in the U.S. The Census Bu-reau reports a total value of shipments in1997 of $968 million; industry estimates put 1999 sales at $1.3 billion just for scented candles, and up to $2.3 billionfor all candles. The majority of candle imports are from China. A large portion of imports come from Hong Kong, Mexico,and Canada as well. There are no public data on incense manufacturers; private data show at least 26 manufacturers. Limited discussions with industry representatives indicate that there are probably many more very small incense manufacturers. The majority of incense imports are from India, China,and Thailand.

Potential Indoor Air Quality Impacts

Scientific literature, consumer interest group reports, and trade and industry stud-ies were consulted for this summary. Re-sources were identified through Medline,Toxline, a database of on-line journals,the National Candle Association, and ex-tensive web searches. The studies were diverse in origin; many of the incense studies were performed in Asia, where incense is commonly burned.Candles According to the literature reviewed, burning candles containing lead-corewicks can result in indoor air concentra-tions of lead above EPA-recommended thresholds.

All three of the scientific stud-ies, found analyzing indoor air concen-trations resulting from burning candleswith lead-core wicks, indicated that thisindoor air threshold was exceeded. Re-garding candles with non-lead metalcores, the literature did not indicate thatwicks made with zinc and tin emitted thesemetals at concentrations that would raisehealth concerns when burned indoors.In addition to lead, consumers are ex-posed to concentrations of organic chemi-cals, such as formaldehyde, acetaldehyde,and acrolein. One study showed worst-case scenario candle emissions contain-ing levels of these three chemicals thatexceeded EPA-recommended thresholds.Other studies indicated no health hazards. Sooting can occur when combustion conditions are impaired when burning candles. Scented candles are more likely to produce soot than unscented candles. Sooting can cause property damage byblackening surfaces. Although soot par-ticles are very small and can potentiallypenetrate the deepest areas of the lungs,studies regarding potential human healtheffects associated with soot from candleswere not found in the literature search.IncenseLarge quantities of particulate matterare generated when burning incense.Studies that examined the emissions ofspecific contaminants from incense smokeindicated that benzene and carbon mon-oxide may be emitted at concentrationsthat could pose human health risks. Sev-eral studies indicated links between exposure to incense smoke and health effects, such as cancer, asthma, and contact dermatitis. Some studies indicated possible mutagenic and genotoxic effects.

    So this is why you should not buy, in my opinion, scented candles or incense sticks that are sold everywhere and produced all over the world, and made of polyaromatic polycyclic substances and mineral formulas derived from petroleum, 100 % synthetic. Hand made incense sticks are really rare nowadays.

    Industry tries to copy nature sinthetically and it's attempt to make money out of inorganic minerals rather than organic living plants, introduces a risk factor that we should take care of. The best way to behave ( when legislations do not take care of public health for some reason or another ), is not to buy a product that contains such substances.

    Incense grains, ritual incenses, and herbs, together with wood and roots, are 100% organic, and if youcan find them "not transformed" or "genetically improved", ( or "cultivated without hormons ") and "without additives" they should be safe. "Bio" already stands for "New" in most of the cases, so don't take care of this word, that has already shown too many times to be a "selling word" rather than a control, which is most of the times carried out by the same firm that makes the product!!!

    Incense sticks and candles, that have had a market expansion of 15% every year in the last decade, and have been "considered by industry" as a way to make a lot of money, are the kind of unnecessay items I would avoid.

  to be continued....work in progress...

look at what I found

United StatesEPA-600/R-01-001Environmental ProtectionAgencyJanuary 2001

Research andDevelopmentCANDLES AND INCENSE ASPOTENTIAL SOURCES OFINDOOR AIR POLLUTION:MARKET ANALYSIS ANDLITERATURE REVIEW

Prepared forOffice of Research and DevelopmentPrepared byNational Risk ManagementResearch LaboratoryResearch Triangle Park, NC 27711
FOREWORDThe U. S. Environmental Protection Agency is charged by Congress with pro-tecting the Nation's land, air, and water resources.

Under a mandate of nationalenvironmental laws, the Agency strives to formulate and implement actions lead-ing to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this mandate, EPA's researchprogram is providing data and technical support for solving environmental pro-blems today and building a science knowledge base  to manage our eco-logical resources wisely, understand how pollutants affect our health, and pre-vent or reduce environmental risks in the future.The National Risk Management Research Laboratory is the Agency's center forinvestigation of technological and management approaches for reducing risksfrom threats to human health and the environment. The focus of the Laboratory'sresearch program is on methods for the prevention and control of pollution to air,land, water, and subsurface resources, protection of water quality in public watersystems; remediation of contaminated sites and-groundwater; and prevention andcontrol of indoor air pollution. The goal of this research effort is to catalyzedevelopment and implementation of innovative, cost-effective environmentaltechnologies; develop scientific and engineering information needed by EPA tosupport regulatory and policy decisions; and provide technical support and infor-mation transfer to ensure effective implementation of environmental regulationsand strategies.This publication has been produced as part of the Laboratory's strategic long-term research plan. It is published and made available by EPA's Office of Re-search and Development to assist the user community and to link researcherswith their clients.E. Timothy Oppelt, DirectorNational Risk Management Research LaboratoryEPA REVIEW NOTICEThis report has been peer and administratively reviewed by the U.S. EnvironmentalProtection Agency, and approved for publication. Mention of trade names orcommercial products does not constitute endorsement or recommendation for use.This document is available to the public through the National Technical InformationService, Springfield, Virginia 22161.

EPA-600/R-01-001January 2001CANDLES AND INCENSE AS POTENTIAL SOURCES OF INDOOR AIR POLLUTION: MARKET ANALYSIS AND LITERATURE REVIEWPREPARED BY:Lynn Knight, Arlene Levin, and Catherine MendenhallEastern Research Group, Inc.110 Hartwell AvenueLexington, MA 02421EPA Contract 68-D7-0001EPA Project Officer: Zhishi GuoNational Risk Management Research LaboratoryResearch Triangle Park, NC 27711PREPARED FOR:U.S. Environmental Protection AgencyOffice of Research and DevelopmentWashington, D.C. 20460
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AbstractThe report summarizes available information on candles and incense as potential sources ofindoor air pollution. It covers (1) market information and (2) a scientific literature review. Themarket information collected focuses on production and sales data, typical uses in the US, anddata on the sources and quantities of imported products. The estimated total sales of candles in1999 varied between $968 million and $2.3 billion, while imports were $486 million. The USimports and exports of incense in 1999 were $12.4 and 4.6 million, respectively. The scientificliterature review gathered information regarding the emission of various contaminants generatedwhen burning candles and incense, as well as the potential health effects associated with exposure to these contaminants. Burning candles and incense can be sources of particulatematter. Burning candles with lead core wicks may result in indoor air concentrations of leadabove EPA-recommended thresholds. Exposure to incense smoke has been linked with severalillnesses, and certain brands of incense also contain chemicals suspected of causing skinirritation.
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Table of ContentsAbstract......................................................................iiTables........................................................................v1. Findings...................................................................11.A Economic Data on Candle and Incense Production and Sales..................11.B Potential Indoor Air Quality Impacts of Burning Candles and Incense...........22. Background.................................................................43. Economic Data on Candle and Incense Production and Sales.........................53.A Candles.............................................................5Number of Candle Manufacturers......................................6Sales.............................................................8Market Trends....................................................11Sources of Imported Candles........................................13Product Use in the US..............................................163.BIncense..........................................................164. Potential Indoor Air Quality Impacts of Burning Candles and Incense.................214.A Candles............................................................21Lead Wick Emissions..............................................22Other Metals.....................................................24Organics.........................................................25
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Particulate Matter.................................................28Candle Soot ......................................................30Conclusion.......................................................324.B Incense............................................................33Carbon Monoxide.................................................34Isoprene.........................................................35Benzene.........................................................35Musk Xylene, Musk Ketone, and Musk Ambrette........................36Particulate Matter..................................................36Polyaromatic Hydrocarbons..........................................37Conclusion.......................................................375. References.................................................................39
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TablesTable 1: Total Sales of Candle Companies in 1999...................................10Table 2: Percent of Candle Sales by Distribution Channel.............................11Table 3: 1999 Candle Imports....................................................14Table 4: Sources of Imported Candles in 1999 ......................................15Table 5: 1999 Imports of Odoriferous Preparations Which Operate By Burning............19Table 6: Indoor Air Impacts of Burning Candles.....................................29
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1. FindingsThe purpose of this report is to collect economic information regarding the production and salesof candles and incense in the US, including information about imports. A second objective is toreview the scientific literature regarding emission rates and potential human health effectsassociated with burning candles and incense. The following is a brief overview of the findings.1.A ECONOMIC DATA ON CANDLE AND INCENSE PRODUCTION AND SALES•The Census Bureau reports 107 manufacturing establishments; however, industryestimates range from 160 to over 200 manufacturers. Many manufacturers are very small. •Candle sales have been growing rapidly in the last 10 years (10 to 15 percent per year),fueled by consumer interest in aroma therapy and increased demand for home fragranceproducts in general.•The Census Bureau reports a total value of shipments in 1997 of $968 million; industryestimates put 1999 sales at $1.3 billion just for scented candles, and up to $2.3 billion forall candles.•The top five countries that export candles to the US are China, Taiwan, England, HongKong, and Mexico.
2
•There are no public data on incense manufacturers; private data show at least 26manufacturers. Limited discussions with some industry representatives indicate that thereare probably many more very small manufacturers.•The top five countries that export incense to the US are India, China, Thailand, Japan, and Hong Kong.1.B POTENTIAL INDOOR AIR QUALITY IMPACTS OF BURNING CANDLES AND INCENSE•Burning candles containing lead core wicks can result in indoor air concentrations of leadabove EPA-recommended thresholds.•In the scientific literature we reviewed, zinc and tin were found not to be emitted atconcentrations that would raise concerns when burned indoors.•One study showed worst-case scenario concentrations of acrolein, formaldehyde, andacetaldehyde from candle emissions exceeding EPA-recommended thresholds. •Sooting can occur when combustion conditions are impaired when burning candles. Scented candles are more likely to produce soot than unscented candles. Sooting can
3
cause property damage by blackening surfaces. We could not identify any studies onpotential human health effects associated with soot from candles.•Several studies indicated links between exposure to incense smoke and health effects,including cancers and contact dermatitis. A few studies indicated possible mutagenic andgenotoxic effects.•Studies that examined the emissions of specific contaminants from incense smokeindicated that benzene and particulate matter may be emitted at concentrations that couldpose human health risks.
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2. BACKGROUNDThe potential indoor air impacts of burning candles and incense have drawn increased attention in recent years. For example, candles with lead wicks have been found on the market and havebeen shown to emit lead when burned. Sooting associated with burning candles can causeproperty damage by blackening walls, ceilings, and carpets. Incense smoke can be a majorsource of particulates in indoor air. Emissions from incense may contain contaminants that cancause a variety of health effects.EPA is currently testing the emissions from candles and incense to generate data for analyzingrisk management options. To support this effort, this report collects and presents information onthe production and sales of candles and incense, the sources and quantities of imported products,and the typical product uses in the US. This information will help EPA in assessing the natureand extent of human exposure. In addition, this report summarizes the results and findings in thescientific literature regarding the emission rates of the various contaminants generated whenburning candles and incense, as well as the potential health effects associated with exposure tothese contaminants. EPA will use this information to further their research and understanding ofthe potential impacts of these sources on indoor air quality.
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3. ECONOMIC DATA ON CANDLE AND INCENSE PRODUCTION AND SALES3.A CANDLESA variety of candle types are manufactured in the US, including tapers, straight-sided dinnercandles, spirals, column, votives, tealights, wax-filled containers, and novelties. Some arescented and all come in a wide range of colors. Wax candles contain petroleum wax, vegetablewax, animal wax, or insect wax as the primary fuel. The wax may contain additives for color,fragrance, stability, or to modify the burning characteristics.Gel candles use liquids such as mineral oil, terpene-type chemicals, or modified hydrocarbons astheir primary fuel. These candles also contain chemical agents to increase the viscosity of thefuel to the point where the candle has a quasi-rigid property.Candles support one or more combustible wicks. Metal is put in some wick cores to keep thewick standing straight when the surrounding wax begins to melt. The metal prevents the wickfrom falling over and extinguishing itself as soon as the wax fails to support it. Many companiesuse a braided wick, which consists of three smaller wicks wound together to provide somestiffness.Lead was commonly used as a core material until 1974 when the US candle manufacturingindustry voluntarily agreed to discontinue use of lead in wicks. There are, however, still candles
on the market that contain lead wick cores. Most of these are imported. Zinc is commonly usedas an alternative metal core for the wicks, since it provides the desired amount of stiffness, burnsoff readily with the rest of the wick, and the airborne particles from zinc wicks are consideredsafer.1Scented candles have grown in popularity and are widely used. The majority of candlemanufacturers offer scented candles. Seventy-five percent of the manufacturers who aremembers of the National Candle Association (NCA) listed fragranced candles among the types ofcandles they produce. Forty percent say they manufacture citronella candles (NCA, 1999).Citronella is an insect repellant.Number of Candle ManufacturersThe candle industry is a relatively small industry and does not have an abundance of publiclyavailable data. The 1997 Economic Census published by the US Census Bureau reports 107manufacturing establishments with a primary North American Industry Classification System(NAICS) product classification code of 3399995, defined as “candles, including tapers” (USCensus Bureau, 1999). These establishments collectively employed 8,536 workers. The CensusBureau has very limited data available since the industry is identified at the 7-digit level.ERG conducted an online search of the Thomas Register of American Manufacturers. This1Telephone communication between Marianne McDermott, Executive Vice President, National CandleAssociation, and Lynn Knight, ERG, August 18, 2000.
6
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search identified 160 candle manufacturers. However, the National Candle Association (NCA)estimates there are over 200 known commercial, religious, and institutional manufacturers ofcandles in the US, as well as many small craft producers (NCA, 1999). The NCA reports that 70of their members are manufacturers and represent roughly 80 percent of the market. The threelargest publicly traded manufacturers are Candle Corporation of America, Candle-Lite, Inc., andThe Yankee Candle Company, Inc. (NCA, 1999). A Merrill Lynch Global Securities analystreported that Yankee Candle Co. accounts for about 10 percent of industry sales. It has 100stores and plans to open 40 per year (Fort Worth Star-Telegram, 1999).A private market study by the Packaged Facts group reports that the candle industry is not onlygrowing, but is undergoing some consolidation. This trend is not limited to smaller companies,but has included some of the leading manufacturers and marketers succumbing to stronger, betterfinanced companies (Packaged Facts, 1999). This source believes that company buyouts aremotivated by parent organizations attracted to making acquisitions in a thriving market and thenhelping these acquisitions grow their product lines and increase market share. For example,Yankee Candle’s partnership with Forstmann Little was reportedly undertaken specifically tofund a major expansion (Packaged Facts, 1999).Internet sales of candles have been increasing. Many smaller candle companies are emerging anddoing well selling their products on the Internet, as the appearance of prominence can be obtained with a nice looking Web site. Selling on the Internet allows these manufacturers to sell
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candles at a reasonable price, since they can pass on savings accrued by avoiding middlemen,slotting fees paid to retailers, and advertising costs (Packaged Facts, 1999).There have been many types of new entrants to the growing candle market. Market researchanalysts believe that new marketers are attracted to this burgeoning market because candles arerelatively simple to make, color, and fragrance, and novelty designs easily attract the buyer’sattention (Packaged Facts, 1999). The scented candles market has seen a lot of cross-categoryencroachment, as fashion designers, perfume manufacturers, and specialty chain marketersintroduce their own lines of candles. For example, upscale retailers, such as The Gap, PotteryBarn, Pier One, and the Bombay Company, are marketing scented candles under their owntrademark. SC Johnson, too, began selling candles fragranced with many of Glade’s air freshenertrademark scents (Packaged Facts, 1999). Meanwhile, dedicated candle outlets, like YankeeCandle, White Barn Candle Company, and Illuminations, are expanding throughout the US(Packaged Facts, 1999).SalesThe 1997 Economic Census reports a total value of shipments for candle manufacturers of $968.3 million. Companies with shipments of $100,000 or more accounted for 98 percent ofshipments, or $951 million. In 1992, shipments for these larger companies were $366 million. The value of shipments increased more than 2.5 times over this 5-year period.
The NCA states that the US candle consumer retail sales for 1999 are reported at $2.3 billion, notincluding candle accessories. NCA further reports that sales of all candles (unscented, scented,and for institutional and religious uses) have been growing 10 to15 percent a year since 19902(NCA, 1999). The Packaged Facts report claims that the growth of scented candles alone is closeto 22 percent per year. This same report estimates that scented candles represent 55 percent of the$2.4 billion total home fragrance market, or $1.3 billion in scented candle sales. Another source,The Freedonia Group, estimated that 1999 candle sales were $1.17 billion.3Unity Marketing, another private marketing research firm, conducts annual surveys among giftmanufacturers who produce and market candles and candle accessories. The most recent survey,which had 37 respondents, was conducted in 2000 and covered 1999 sales. The survey resultsshowed an upward trend in total annual sales for 1999, with average company sales amongrespondents up 39 percent from $10 million in 1997 to $14 million in 2000. In 1999, 39 percentof companies surveyed reported annual sales of more than $10 million as compared with only 27percent in 1997. (See Table 1.)2 The source of these estimates is not disclosed in the NCA publication.3 This figure was interpreted from the Freedonia Group’s prediction that sales would increase 8.1 percent annually to reach $1.6 billion in 2003.
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10
Total Annual Sales(Dollars in Thousands)
Percent of CandleCompanies Surveyeda
> $50,000
12
$26,000 - $50,000
9
$11,000 - $25,000
18
$6,000 - $10,000
9
$1,000 - $5,000
27
$500 - $999
15
<$500
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aThese statistics do not cover only candle manufacturing. They include manufacturers of candle accessories as well. Fifty-three percent of companies surveyed owned their own factory facilities. Figures do not add to 100 percent.Source: Unity Marketing, 2000.
Table 1: Total Sales of Candle Companies in 1999
Candles are sold through a variety of distribution channels. According to the Unity Marketingsurvey, specialty retail stores capture a large portion of candle sales. (See Table 2.) PackagedFacts estimates that 51 percent of 1998 scented candle sales were attributable to massmerchandisers, 36 percent to supermarkets, and 13 percent to drug stores. (Unity Marketing andPackaged Facts each based their estimates on different distribution channel categories, thus notallowing direct comparisons.)
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Distribution Channel
Percent of Total
Specialty Retail Stores (gift, card, collectible,and decorative accessory shops)
68
Department Stores
9
Mass Merchandisers and Discounters
8
Internet
4
Consumer Direct Marketing(catalogs, direct response ads, or promotionalmailings)
4
Other
7
Source: Unity Marketing, 2000.
Table 2: Percent of Candle Sales by Distribution Channel
Market TrendsIn their reporting of product statistics, the Economic Census reports nearly a doubling in thenumber of candle manufacturers from 1992 to 1997. As discussed above, recent years haveshown new entrants to the candle manufacturing industry. Although many new manufacturershave entered the market, according to a the Unity Marketing survey, the majority (75 percent) ofgift manufacturers that produce and market candles and candle accessories have been in thebusiness for a long time. Half of the companies in the survey have been in business for 11 to 25years, while another 25 percent have been in business longer.The NCA reports that, in the last 5 years, the industry has doubled its sales. Trade associationsources as well as numerous trade publication articles attribute this tremendous growth to the
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rapid increase in sales of aroma therapy and other scented candles. A supermarket tradepublication reported that in 1999, candles were generating annual sales increases of around 20percent (Supermarket News, 1999). The same publication states that retailers and suppliersattribute the upswing in sales to the fact that consumers view candles as a relatively cheap andaccessible fashion accessory for the home for special events or seasonal decoration, or just as anaccessible means of augmenting the atmosphere within the home.Shipments of candles are forecast by the Freedonia Group, a private research firm, to expand 8.1percent per year reaching $1.6 billion in 2003 (The Freedonia Group, Inc., 1999). They predictthat, in addition to the mature market for ceremonial and utilitarian lighting applications,introduction of numerous fashion-driven, upscale offerings and mood-enhancing scentedvarieties, will spur gains; as will the increasing market presence of candle-only stores. Supermarkets, drug store chains, and upscale department stores have all expanded their candleofferings, including displays in multiple departments, such as air-freshener, body/bath sections,and health and beauty products displays.The Freedonia Group report predicts that the pace of growth will slow from the double-digitincreases of the earlier decade, due to increased competition from imports and some loss ofconsumer interest. This is in contrast to the Packaged Facts report that observes that, even though the trade press has previously reported that the popularity of candles and potpourri usually alternates on a 5-year cycle, candles are continuing to sell beyond that cycle and are
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showing no signs of slowing down.Another business publication reports that candles are the largest growing segment in the giftwaremarket. Sales have been buoyed by the introduction of high-fashion candle stands and displayaccessories as well as innovations in candle design, shape, color, and fragrances. Longer lastingscents and unique decorative styles have attracted buyers. Females between the ages of 25 and 54with household annual incomes over $25,000 are the prime market. Men purchase candles atabout half the rate of women (Business Wire, 1999).Sources of Imported CandlesThe Census Bureau tallies import data from the various ports of entry by originating country. These data show that in 1999, China, Hong Kong, Mexico, and Canada were the largest suppliersof candle imports. (See Table 3.) A total of 197.9 million kg of candles valued at $484.2 millionwere imported in 1999. The Freedonia Group reports that candle imports more than tripledbetween 1993 and 1998.Unity Marketing investigated the sources of imports when surveying candle manufacturers. (SeeTable 4.) This survey showed that 68 percent of companies reported China as the top countrysupplying imported candles.
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Country of Origin
Quantity (kg)
Percent of Total
Custom Value
China
68,922,143
34.8
$131,759,756
Hong Kong
26,506,500
13.4
$53,548,145
Mexico
25,449,253
12.9
$50,868,810
Canada
24,781,312
12.5
$73,683,421
Guatemala
8,529,417
4.3
$55,737,602
Israel
8,395,482
4.2
$19,425,929
Thailand
7,532,504
3.8
$18,439,677
Taiwan
6,876,205
3.5
$17,525,569
Italy
4,722,934
2.4
$13,162,283
El Salvador
2,594,292
1.3
$3,332,61
Macao
2,227,634
1.1
$4,474,057
aTable includes data only from countries supplying 1 percent or greater of the total quantity of imports.Source: US Bureau of the Census, 2000.
Table 3: 1999 Candle Importsa
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Country
Percent of CompaniesSurveyed
China
68
Taiwan
40
England
36
Hong Kong
36
Mexico
36
Philippines
25
Thailand
25
Indonesia
21
France
18
Italy
18
Malaysia
18
Germany
14
Japan
14
Spain
11
Australia & New Zealand
7
Ireland
7
Poland
7
India
7
Brazil
4
Canada
4
Singapore
4
Other
7
Source: Candle Report, Unity Marketing, 2000.
Table 4: Sources of Imported Candles in 1999
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Product Use in the USCandles are purchased for utilitarian, religious, or other institutional purposes, but the majority ofcandles, particularly scented candles, are purchased for non-utilitarian home use. Consumersbuying scented candles derive utility from the decorative and aromatic attributes of the candles. The NCA reports that 7 out of 10 US households use candles, and candle manufacturers’ surveysshow that 96 percent of all candles purchased are bought by women (NCA, 1999).Some candles are purchased for special events, such as parties, or for seasonal decorations. Thuscandle sales do especially well in parts of the country that experience four seasons. Impulsebuying accounts for a significant portion of purchases on a regular basis because people areattracted to the scent when they encounter candles while shopping (Supermarket News, 1999).People encounter candles more often as supermarkets, drug stores, and mass-merchandisersincrease their candle offerings. Candles are sold alongside floral and gift merchandise, as well asgreeting cards. Candles for home decorating and fragrance have broad appeal, crossing alldemographic lines (Supermarket News, 1999). The NCA reports that seasonal (e.g., Christmasand other holidays) buying accounts for roughly 35 percent of sales (NCA, 1999).3.BINCENSEIncense has been used for centuries for ceremonial purposes as well as to fragrance theenvironment, conceal undesired ambient odors, or freshen clothing. Most incense is made from acombination of fragrant gums, resins, woods, and spices. One traditional method of makingincense is to prepare a paste of pulverized botanicals, water, and charcoal and wrap the paste
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around a bamboo twig. After the twig dries, it is dipped into perfumed essential oils or powders.Incense is available in sticks, cones, rods, coils, small blocks, wands, and powders (PackagedFacts, 1999).The US Census Bureau does not maintain data to the level of detail required to capture incensemanufacturers. Economic data for incense manufacturers are aggregated under NAICS materialcode 325998, which is defined as other miscellaneous chemical products, manufacturers ofchemical preparations not elsewhere classified, including essential oils. This category coversproduction of all types of essential oils, pyrotechnics, fireworks, drilling muds, and otherindustrial preparations, such as foundry and rubber processing supplies. ERG was unable to finda detailed source of government data covering specifically incense manufacturing and sales.The Thomas Register of American Manufacturers on-line database lists 26 companies asmanufacturers of incense. After contacting nine of the companies listed, we were able to findvery little additional information about incense manufacturing in the US. One companyrepresentative said that many companies listed as manufacturers may indeed be repackagers whoimport incense and repackage it for sale in the US. Another stated that there are many domesticmanufacturers that are very small—possibly single individuals making incense for sale locally. One manufacturer contacted claimed they had $500,000 in annual sales.The US Census Bureau data on domestic exports for 1999 show a total value of $4.6 million forincense. This figure represents total exports worldwide. The highest percentages of exports
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went to Canada, followed by Mexico, the United Kingdom, and Japan. Quantities (weight) ofexports were not reported.The Census Bureau also reports data on imports of incense to the US. In 1999, $12.4 million ofincense was imported to the US. The largest percentage of imports came from India, followed byChina, Thailand, and Japan. (See Table 5.)
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Country of Origin
Value of Imports
Percent of Total
India
$3,308,591
26.7
China
$2,290,454
18.5
Thailand
$2,178,078
17.6
Japan
$1,645,833
13.3
Hong Kong
$891,850
7.2
United Kingdom
$549,540
4.4
Mexico
$507,586
4.1
Othera
$459,572
3.7
France
$450,941
3.5
Vietnam
$126,002
1.0
Total World
$12,408,447
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aCountries each supplying less than 1 percent of imports, including Canada,
The Netherlands, Belgium, Germany, Italy, Greece, Syria, Israel, Saudi Arabia,
Pakistan, Nepal, Burma, Indonesia, Macao, Korea, Taiwan, Australia, Egypt,
and Ethiopia.
Source: US Census Bureau
Table 5: 1999 Imports of Odoriferous Preparations Which Operate By Burning
Given that $12.4 million worth of incense is imported to the US, and $4.6 million is produceddomestically for export, the US market for incense is at least $17 million, excluding the value ofwhat is produced domestically for domestic consumption.Descriptive literature on the incense industry is very limited. Only one article was found despitea thorough search of market literature databases. This article discussed the incensemanufacturing industry in Japan. It reported that the largest Japanese manufacturer of incense isNippon Kodo Co. Ltd., who manufactures more than 2,000 fragrance products made from naturalmaterials. One-third of its annual turnover is derived from overseas markets, including Europe
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and the US. Company officials claim they control more than 50 percent of the incense market inthe country. The company has six plants in Japan, one in Taiwan, and one in Hong Kong andimports its raw materials from Vietnam and Indonesia. This year, the company began distributing incense in Malaysia to satisfy the increasing demand for environmentally friendlyincense for religious, home fragrance, and anti-stress purposes (Bernama, 2000).
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4. POTENTIAL INDOOR AIR QUALITY IMPACTS OF BURNING CANDLES AND INCENSE

4.A CANDLESWhen candles are burned, they emit trace amounts of organic chemicals, including acetaldehyde,formaldehyde, acrolein, and naphthalene (Lau et al., 1997). However, the primary constituent ofpublic health concern in candle emissions is lead. Metal was originally put in wicks to keep thewick standing straight when the surrounding wax begins to melt. The metal prevents the wickfrom falling over and extinguishing itself as soon as the wax fails to support it. The US candlemanufacturing industry voluntarily agreed to cease production of lead-containing candles in1974, once it was shown that burning lead-wick candles resulted in increased lead concentrationsin indoor air (Sobel et al., 2000b). Unfortunately, despite the voluntary ban, lead wick candlescan still be found on the market.According to the National Candle Association (NCA), most US candle manufacturers haveabided by the agreement to cease lead wick production. All of the NCA members have signedpledges not to use lead wicks in candles they manufacture. In addition, the NCA has sent a letterto all the candle manufacturers registered with the Thomas Register of American Manufacturersinforming them of the potentially adverse health effects associated with wicks that contain leadand asking them to sign pledges not to use wicks containing lead in their candles. The NCA hasalso sent letters to retailer trade associations to inform them of this issue.The NCA states that only a small number (one or two) of candle manufacturers make their own
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wicks. The rest purchase wicks from wick manufacturers. One such manufacturer is Atkins andPearce, Inc.; they claim to have stopped making and selling wicks with lead in 1999.The Candle Product Subcommittee of the American Society of Testing and Materials (ASTM) isworking on voluntary standards for candle content, including labeling standards. It is anticipatedthat this standard will address the lead issue. The draft standard was presented at the fall 2000ASTM meeting.There have been limited investigations regarding the prevalence and source of candles with leadwicks. ERG did not find any statistical studies investigating the presence of lead-wick candles inthe US marketplace. However, a handful of studies contain some information about theoccurrence of lead-wick candles in the local study areas. The following discussion and Table 6present information on lead and other chemicals emitted from candles.Lead Wick EmissionsIn February 2000, the Public Citizen’s Health Research Group conducted a study of the leadcontent of candles in the Baltimore-Washington area. They purchased 285 candles from 12stores, excluding candle-only stores, and tested the wicks for the presence of lead. They foundthat nine candles, or 3% of the candles they purchased, contained lead. Total lead content rangedfrom approximately 24,000 to 118,000 μg (33 to 85% of the weight of the metal in the candlewick).
An academic study was conducted on the emissions of lead and zinc from candles with metal-core wicks (Nriagu and Kim, 2000). For this study, the researchers purchased and tested candles(found in Michigan stores) that had metal-core wicks. Fourteen brands of candles manufacturedin the US, Mexico, and China were found to contain lead. Emission rates from candles rangedfrom 0.52 to 327 μg-lead/hour, resulting in lead levels in air ranging from 0.02 to 13.1 μg/m3.These concentrations are below the Occupational Safety and Health Administration (OSHA)Permissible Exposure Limit4 (PEL) of 50 μg/m3, but above the EPA outdoor ambient air qualitystandard5 of 1.5 μg/m3. It is important to note that, although the EPA standard was not developedfor use for indoor air comparisons, it is used throughout this report as a conservative comparisonvalue. OSHA’s PEL values should also be interpreted with some caution for they areoccupational standards not designed for the protection of the general public, children, or sensitivepopulations.Another prominent study, van Alphen (1999), examined emissions and inhalation exposure-based risks for candles having lead wick cores. The mean emission rate was 770 μg-lead/hour,with a range of 450 to 1,130 μg-lead/hour. A candle burned for 3 hours at 1,000 μg-lead/hourin a 50 m3 room with poor ventilation is estimated to yield a 24-hour lead concentration of 9.9μg/m3, and a peak concentration of 42.1 μg/m3. OSHA’s 50 μg/m3 PEL is not approached in this4PEL (Permissible Exposure Limit): These OSHA standards were designed to provide health protection for industry employees by regulating exposure to over 300 chemicals. PELs are an 8-hour time weighted average. 5EPA Outdoor Ambient Air Quality Standards: Required by the Clean Air Act, these standards were set forpollutants thought to harm public health and the environment, including the health of "sensitive" populations such as asthmatics, children, and the elderly.
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study, but again, EPA’s outdoor ambient air standard of 1.5 μg/m3 is exceeded.Sobel et al. (2000a) modeled lead emissions from candles containing lead wicks. After burningmultiple candles in a contained room, 24-hour lead concentrations ranged from 15.2 to 54.0μg/m3. The candle containing the least amount of lead produced lead concentrations of 30.6μg/m3 in 3 hours. The maximum concentration of 54 μg/m3 is above the PEL standard of 50μg/m3 and EPA’s outdoor ambient air quality standard of 1.5 μg/m3.Other MetalsZincAfter the ban on lead-containing wicks, candle companies began looking for alternatives thatprovided the desired characteristics of the lead wick without the harmful emissions. Manycompanies turned to braided wicks, which consist of three smaller wicks wound together toprovide some stiffness. Zinc cores are also commonly used, since the metal provides the desiredamount of stiffness, burns off readily with the rest of the wick, and does not have the same toxiceffects as lead.Zinc is an essential element for human health. However, inhaling large amounts of zinc (as zincdust or fumes from smelting or welding) over a short period of time (acute exposure) can causea disease called metal fume fever. Very little is known about the long-term effects of breathingzinc dust or fumes (Eco-USA.net, 2000).
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Nriagu and Kim (2000) found the release of zinc from metal-core wicks to be 1.2 to 124μg/hour, which is too low to be of health concern in indoor air. All nonferrous metals havetraces of lead impurities; for zinc, the maximum lead content is 0.004% (Barker Co., 2000). The lead emissions from zinc wicks are below the detection level of most test methods (BarkerCo., 2000), though one study found emission rates of 0.014 μg-lead/hour (Ungers andAssociates, 2000).TinTin is also commonly used as a stiffener for candle wicks. It is considered to be nontoxic(Chemglobe, 2000). Tin has a maximum lead content of 0.08%, but, like zinc, lead emissionsare below the detection limit when tin wicks are burned (Barker Co., 2000).OrganicsSeveral organic compounds have been detected in candle emissions. Three articles havefocused specifically on this topic. Lau et al. (1997) measured levels of selected compounds incandle materials and modeled human exposure to a worst-case scenario of 30 candles burned for3 hours in a 40 m3 room with realistic air flow conditions. Schwind and Hosseinpour (1994)analyzed candle materials and the combustion process, and created a worst-case scenario of 30candles burned for 4 hours in a 50 m3 room with approximately 0.7 L/min air flow. Fine et al.(1999) also performed a series of emission tests on the combustion of paraffin and beeswax
candles burned in an air chamber with a volume of approximately 0.64 m3 and an air flow rateof 100 L/min. Results of the studies are presented below and in Table 6.Acetaldehyde610-6 excess cancer risk level: This EPA comparison value is the air concentration known to produce an increased risk of 1 in 1,000,000 for cancer.7RfC (Reference Concentration): This EPA health-based comparison value assumes that there is a threshold forcertain toxic effects. The RfC is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily inhalation exposure of the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. 8STEL (Short-Term Exposure Level): This OSHA standard was designed to limit maximum concentrations ofexposure as averaged over any 15 minute period. This is an occupational standard, not designed for the protection of the general public, children, or sensitive populations. Acetaldehyde levels for 30 candles burned in an enclosed room for 3 hours were modeled at0.834 μg/m3 (Lau et al., 1997); this is above the EPA’s 10-6 excess cancer risk level6 of 0.5μg/m3, but below the EPA inhalation reference concentration (RfC)7 of 9 μg/m3.Formaldehyde Formaldehyde levels were measured at 0.190 μg/m3 (Lau et al., 1997) and 17 μg/m3 (Schwindand Hosseinpour, 1994). Again, these measurements were above the EPA’s 10-6 excess cancerrisk level of 0.08 μg/m3, but below the OSHA PEL maximum of 921.1 μg/m3. Formaldehydelevels for both studies were far below OSHA’s STEL8 maximum of 2,456.1 μg/m3.AcroleinMaximum concentrations of acrolein were measured at 0.073 μg/m3 (Lau et al., 1997) and <1μg/m3 (Schwind and Hosseinpour, 1994). These levels are above the RfC of 0.02 μg/m3 and
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below the PEL of 250 μg/m3. A cigarette burned in a similar environment produces acroleinlevels of 23 μg/m3 (Lau et al., 1997).Polychlorodibenzo-p-dioxins/Polychlorodibenzofurans (PCDD/PCDF)Levels of PCDD/PCDF were measured at 0.038 pg I-TEQ/m3 (Schwind and Hosseinpour, 1994). The TEQ is the toxic equivalency method used to evaluate dioxins. It represents the sumof the concentrations of the multiple dioxin congeners "adjusted" to account for the toxicity ofeach congener relative to the most toxic dioxin, 2,3,7,8-TCDD.Polyaromatic Hydrocarbons (PAHs)The amount of PAHs measured in candle emissions and soot differs between studies. Fine et al.(1999) found that no significant levels of PAHs were detected in the emissions from normalburning and smoldering candles. In contrast, Huynh et al. (1991) found that soot from wax-lightchurch candles contained measurable concentrations of PAHs: the study measured 882 μgbenzo[ghi]perylene per gram of candle soot and 163 μg benzo[a]pyrene per gram of candle soot. However, Huynh et al. did not measure PAH concentrations from candles in air. Wallace (2000) also concluded that a citronella candle was a source of PAHs in a study of real-timemonitoring of PAHs in an occupied townhouse, but did not quantify the concentration oremission rate.Concentrations of benzo[a]pyrene in air due to candle emissions can measure 0.002 μg/m3 (Lau et al., 1997). This is below the PEL value of 200 μg/m3. Naphthalene maximum concentration
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levels were measured at 0.04 μg/m3 (Schwind and Hosseinpour, 1994), below the EPA RfC of 3μg/m3.Alkanes, Wax Esters, Alkanoic and Alkenoic Acids, AlkenesFine et al. (1999) found that the majority of emissions from candles consisted of organiccompounds including alkanes, wax esters, alkanoic and alkenoic acids, and alkenes. Some of the compounds found were thermally altered products of the unburned wax, while others wereunaltered in the volatilization process. Concentrations of the organic compounds in air were notcalculated.Particulate MatterThe diameter of candle flame particles have been measured between 20 and 100 nm (Li andHopke, 1993) and 100 and 800 nm depending on the mode of burning (Fine et al. 1999). Neither study calculated maximum concentrations of particles in air. Li and Hopke (1993)subjected candle flame particles to relative humidity comparable to that in the human respiratorytract, and found that candle flame particles grew in size. White candles had a 20% larger growth potential than scented candles.
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Table 6: Indoor Air Impacts of Burning Candles
Contaminant
Study
MaximumConcentration
STEL
PEL
RfC
10-6ExcessCancer Risk
Lead
Nriagu andKim
3 0.02- 13.1 μg/m
NA
350 μg/m
NA
NA
van Alphen
3 42.1 μg/m
Sobel etal.(2000a)
15.2 to 54.03 μg/m
Zinc
Nriagu andKim
1.2-124 μg/hour a
NA
NA
NA
NA
Tin
NA
NA
NA
NA
NA
NA
Acetaldehyde
Lau et al.
3 0.834 μg/m
NA
360,0003μg/m
39 μg/m
30.5 μg/m
Formaldehyde
Lau et al.
30.190 μg/m
2,456.13μg/m
921.13μg/m
NA
30.08 μg/m
Schwind andHosseinpour
317 μg/m
Acrolein
Lau et al.
30.073 μg/m
NA
3250 μg/m
0.023μg/m
NA
Schwind andHosseinpour
3<1 μg/m
PCDD/PCDF
Schwind andHosseinpour
0.038 pg I-3TEQ/m
NA
NA
NA
NA
Benzo [a]pyrene
Lau et al.
30.002 μg/m
NA
20013μg/m
NA
NA
Naphthalene
Schwind andHosseinpour
30.04 μg/m
NA
50,0003μg/m
33 μg/m
NA
Alkanes, WaxEsters,Alkanoic andAlkenoicAcids,Alkenes
NA
NA
NA
NA
NA
NA
Particulate
NA
NA
NA
NA
NA
NA
aThis number represents an emission rate, not a concentration. A maximum concentration was not calculated for zinc. ( sorry for the mess.. )
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Candle Soot Black Soot Deposition (BSD) is also referred to as ghosting, carbon tracking, carbon tracing, and dirty house syndrome. Complaints of BSD have risen significantly since 1992 (Krause,1999).Black soot is the product of the incomplete combustion of carbon-containing fuels. Completecombustion would result in a blue flame, and would produce negligible amounts of soot andcarbon monoxide. Until recently, the source for the black soot in homes was unknown. Through interviews and recent experiments, it is now believed that frequent candle burning is one of the sources of black soot. The amount of soot produced can vary greatly from candle tocandle. One type of candle can produce as much as 100 times more soot than another type(Krause, 1999). For example, elemental carbon emission rates varied from <40 to 3,370 μg/gcandle burned in a study of sooting behavior in candles (Fine et al., 1999). The type of soot mayalso vary; though primarily composed of elemental carbon, candle soot may include phthalates,lead, and volatiles such as benzene and toluene (Krause, 1999).Scented candles are the major source of candle soot deposition. Most candle wax paraffins are saturated hydrocarbons that are solid at room temperature. Most fragrance oils are unsaturatedhydrocarbons and are liquid at room temperature. The lower the carbon-to-hydrogen ratio, theless soot is produced by the flame. Therefore, waxes that have more fragrances in them produce
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more soot. In other words, candles labeled “super scented” and those that are soft to the touchare more likely to generate soot.The situation in which a candle is burned can also impact its sooting potential. A small andstable flame has a lower emission rate than a larger flickering flame with visible black particleemissions (Vigil, 1998). A forced air flow around the flame can also cause sporadic sootingbehavior (Fine et al., 1999). Thus, candles in glass containers produce more soot because thecontainer causes unsteady air flow and disturbs the flame shape (Stephen et al., 2000). Candlesthat are extinguished by oxygen deprivation, or blowing out the candle, produce more soot thanthose extinguished by cutting off the tip of the wick. Cutting the wick eliminates the emissionsproduced by a smoldering candle (Stephen et al., 2000).When soot builds up in air, it eventually deposits onto surfaces due to one of four factors. First,the particle may randomly collide with a surface. Second, soot particles can be circulated bypassing through home air-conditioning filters. Third, soot can gain enough mass to becomesubject to gravity. Homes with BSD often have carpets stained from soot deposition (Vigil,1998). Finally, the particles are attracted to electrically charged surfaces such as freezers, vertical plastic blinds, television sets, and computers (Krause, 1999).
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When soot is airborne, it is subject to inhalation. The particles can potentially penetrate thedeepest areas of the lungs, the lower respiratory tract and alveoli (Krause, 1999). ERG did notfind research literature on the health effects of residential exposure to candle soot.ConclusionCandles with lead wicks have the potential to generate indoor airborne lead concentrations ofhealth concern. It is also possible for consumers to unknowingly purchase candles containinglead wick cores and repeatedly expose themselves to harmful amounts of lead through regularcandle-burning.Lead wicks aside, consumers are also exposed to concentrations of organic chemicals in candleemissions. The European Candle Association (1997) and Schwind and Hosseinpour (1994)conclude that there is no health hazard associated with candle burning even when a worst-casescenario of 30 candles burning for 4 hours in a 50 m3 room is assumed. However, burningseveral candles exceeded the EPA’s 10-6 increased risk for cancer for acetaldehyde andformaldehyde, and exceeded the RfC for acrolein. Once again, the RfC and EPA’s 10-6 increased cancer risk guidelines are not designed specifically for indoor air quality issues, sothese conclusions are subject to interpretation.
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Consumers may also not be aware that the regular burning of candles may result in BSD, causing damage to their homes. Sooting can be reduced by keeping candle wicks short, drafts toa minimum, and burning unscented candles.Additional research may want to focus on gaps in the literature, such as emissions from scentedand multi-colored candles, and maximum concentrations of organics in air produced by sootingcandles.4.B INCENSESeveral studies found associations between exposure to incense smoke and many illnesses,including cancer, asthma, and contact dermatitis. Incense burning was found to be a contributingfactor in the occurrence of asthma for Quatar children (Dawod and Hussain, 1995), and coughingwas found to be associated with incense exposure in a study of Taiwanese children (Yang et al.,1997). Burning incense produces volatile fragrances that, once airborne, can reach exposed skin,causing dermatitis (Roveri et al., 1998). An elevated risk for leukemia was found in childrenwhose parents burned incense during pregnancy or while nursing (Lowengart et al., 1987). Astudy of childhood brain tumors showed elevated risk for children whose parents burned incensein the home (Preston-Martin et al., 1982).From comparing mutagenic potencies of incense, formaldehyde, and acetaldehyde to Salmonellatyphimurium T102, Chang et al. (1997) concluded that incense smoke contains highly active
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compounds with a higher mutagenic potency than formaldehyde. Sato et al. (1980) andRasmussen (1987) have also found that incense smoke is mutagenic to S. typhimurium TA98, TA100, and TA104. Incense Smoke Condensates (ISCs), the particles released during incenseburning, were found to be mutagenic and/or genotoxic in the Ames test, the SOS chromotest, andthe SCE/CHO assays. The genotoxicity of certain ISCs in mammalian cells was also found to behigher than particles produced from tobacco smoke condensates (TSCs) (Chen et al., 1990).Interestingly, one study concluded that burning incense decreases the chances of developing lungcancer (Liu et al., 1993). However, this study was conducted in China, where societal factorsmay have influenced the results of the study. For example, people using incense may be morewell off and therefore have healthier life styles in general (Liu et al., 1993). A few studiesexamined emissions of specific contaminants from incense smoke. These results are discussedbelow.Carbon MonoxideCarbon monoxide inhibits the blood's ability to carry oxygen to body tissues including vitalorgans such as the heart and brain. Symptoms of carbon monoxide exposure vary widely basedon exposure level, duration, and the general health and age of an individual. Typical symptomsinclude headache, dizziness, and nausea. These 'flu like' symptoms often result in a misdiagnosisand can cause delayed or misdirected treatment. Contact with high levels of carbon monoxidecan result in unconsciousness and death (EPA, 2000b).
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Although Löfroth et al. (1991) found that burning incense produced sizeable amounts of carbonmonoxide (220 mg/g incense burned), the authors concluded that it is not likely to exceed EPAregulatory standards unless the incense is burned in a very small room with very little ventilation. The standard used for a comparison value in the study was the EPA’s outdoor ambient air qualitystandard of 10 mg/m3. This is not necessarily the most appropriate comparison value, especiallysince mg/g incense burned, not maximum indoor air concentration, was reported.IsopreneIsoprene is a hydrocarbon created and emitted from plants and trees during respiration, and hasalso been detected in tobacco smoke and automobile exhaust. Isoprene does have genotoxicproperties (EDF, 2000).Interestingly, the predominant exposure to isoprene comes from its formation in the human body. An exhaled breath contains 1-3 mg/m3 of isoprene. Löfroth et al. (1991) concluded that 1.1 mgisoprene/g incense burned would not result in adverse health effects. Again, maximum indoor air concentrations were not provided in this study.BenzeneLöfroth et al. (1991) compared benzene emissions from the food preparation process, cigarettesmoking, and burning incense. The study found that emissions of benzene resulting from burning an incense cone were 440 μg/g incense burned. Löfroth et al. concluded that this
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emission level could possibly cause an increase in indoor benzene concentrations above urban airbackground levels of 2-20 μg/m3. A maximum indoor benzene concentration was not calculatedin this study, so we cannot justifiably compare Löfroth’s value to the EPA 10-6 excess cancer riskestimates, reported as a range of 0.13 to 45 μg/m3 (EPA, 2000a).Musk Xylene, Musk Ketone, and Musk AmbretteMusk xylene (2,4,6-trinitro-1,3-dimethyl-5-tertiary butyl benzene), musk ketone (3,5-dinitro-2,6-dimethly-4-tertiary butyl acetophenone), and musk ambrette (2-methoxy-3,5 dinitro-4-methyl-tertiary butylbenzene) are contained in some types of Chinese incense (Roveri et al., 1998). Theyare known for making skin more sensitive to light and causing irritations. When incense isburned, airborne particles may dissolve in the upper layer of skin and allergic contact dermatitismay arise. However, toxicity and health data for these chemicals are not available.Particulate MatterBurning incense was found to generate large quantities of particulate matter (Mannix et al.,1996). Mannix et al. estimated the median diameter of particulates in aerosols to be between 0.24 and 0.40 μm, and hypothesize that particles could deposit in the respiratory tract. Mannix etal. did not perform a chemical characterization of compounds present in the particulate phase, butrecommend that a human exposure scenario be done. Li and Hopke (1993) also found thatincense smoke produced larger particles, in the range of 0.1 to 0.7 μm. Tung et al. (1999) foundthat PM10 concentrations in Hong Kong homes were 23% higher with smoking or incense
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burning– the mean indoor PM10 level for all homes was 78.8 μg/m3, while mean PM10 forsmoking or incense-burning homes was 96.6 μg/m3. This is below the EPA’s national ambientair quality 24-hour standard of 150 μg/m3, but above the annual standard of 50 μg/m3. Chao et al. (1998) found that burning incense in a home with poor ventilation could result in a peakconcentration of total suspended particulates (TSPs) of 1,850 μg/m3. In 1987, EPA began usingPM10, particles measuring 10 μm or less in diameter, rather than TSPs as the standard unit ofmeasure. However, before that time, the standard for outdoor TSPs in the United States was 260μg/m3 for a 24-hour average and 75 μg/m3 for an annual average. The concentration ofparticulates found in Chao et al. (1998) far exceeds 260 μg/m3.Polyaromatic Hydrocarbons (PAHs)Reports of PAHs in incense soot have been contradictory. Chang et al. (1997) did not find PAHsin the vapor extract of incense smoke. However, Koo (1994) determined that PAH levels rosewith incense burning in a study of Hong Kong residences. Incense soot was found to containmeasurable concentrations of fluoranthene, pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene,benzo[a]pyrene, dibenzo[def,p]chrysene, benzo[ghi]perylene, ideno[1,2,3,-cd]pyrene,anthanthrene, and coronene (Huynh et al., 1991). Though the study established that themaximum dust concentration corresponded with the burning of incense, maximum concentrations of PAHs from incense burning were not calculated.
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ConclusionIncense produces particulate matter that can deposit in the respiratory tract, and elevates airborne concentrations of carbon monoxide and benzene. Incense also contains trace amounts of chemicals suspected of causing skin irritation, and exposure to incense has been linked with several illnesses. Incense smoke should be considered a source of indoor pollutants in rooms in which incense is regularly burned (Cheng and Bechtold, 1995). However, the studies reviewed measured emissions for only a limited number of incense types and brands; with the large range of incense manufacturers and importers on the market, other incense types could differ in the parameters examined.