United States
                 Environmental Protection
                                  National Risk Management
                                  Research Laboratory
                                  Cincinnati, OH 45268
                 Research and Development
                                  EPA/600/SR-01/001  January 2001
Project Summary
                 Candles and Incense  as Potential
                 Sources of  Indoor Air  Pollution:
                 Market  Analysis  and Literature
                 Lynn Knight, Arlene Levin, and Catherine Mendenhall
                  The report summarizes available in-
                formation on candles and incense as
                potential sources of indoor air pollution.
                It covers market information and a re-
                view of the scientific literature.  The
                market information collected focuses
                on  production and sales data,  typical
                uses in the U.S., and data on the sources
                and quantities of imported products. The
                estimated total sales of candles in 1999
                varied  between $968  million and $2.3
                billion,  while imports were $486 million.
                The U.S. imports and exports of incense
                in 1999 were $12.4 and 4.6 million, re-
                spectively. The scientific literature re-
                view gathered information regarding the
                emission of various contaminants gen-
                erated  when  burning  candles and in-
                cense,  as well as the potential health
                effects associated with  exposure to
                these contaminants. Burning candles
                and incense can be sources of particu-
                late matter. Burning candles with lead-
                core wicks  may result in  indoor air
                concentration of lead above EPA-rec-
                ommended thresholds. Exposure to in-
                cense  smoke has been linked with
                several illnesses, and certain brands of
                incense also contain chemicals sus-
                pected  of causing skin irritation.
                  This Project Summary was developed
                by  the  National Risk Management Re-
                search Laboratory's Air Pollution Pre-
                vention and Control Division, Research
                Triangle Park, NC, to announce key find-
                ings of the research project that is fully
                documented in a separate report of the
                same title (see Project Report ordering
                information at back).
                                  Background and Approach
                                    The potential indoor air impacts of burn-
                                  ing candles and incense have drawn in-
                                  creased attention in recent years. There
                                  are  three particular areas of concern.
                                  Candles with lead-core wicks have been
                                  found on the market and have  been
                                  shown to be a source of airborne lead
                                  when burned. Metal cores are  used to
                                  stiffen wicks so they will not fall over and
                                  extinguish themselves  as the surround-
                                  ing wax melts. Lead was commonly used
                                  as a core material until 1974 when the
                                  U.S.  candle manufacturing industry vol-
                                  untarily agreed to discontinue use of lead
                                  in wicks.  However,  candles with lead
                                  wicks have been found on the market by
                                  an academic as well as a consumer pro-
                                  tection group study. Most of the candles
                                  found that contained lead wicks were im-
                                    Secondly, under imperfect combustion
                                  conditions, candles emit soot and can
                                  cause property damage by blackening
                                  walls, ceilings, and carpets. There have
                                  been an increasing number of complaints
                                  regarding black soot deposition in homes
                                  in the last decade. Candles are  one
                                  source of soot. With candles, sooting oc-
                                  curs as a result of incomplete combus-
                                  tion. Candle composition, wick length, and
                                  drafty conditions can all affect candle com-
                                  bustion. The amount of soot produced
                                  can vary greatly depending on the type of
                                  candle. One type of candle can produce
                                  as much as 100 times more soot than
                                    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 respiratory
tract. These emissions may contain con-
taminants that  can  cause  a  variety of
health effects, including mutagenic effects
and airborne dermatitis.
  EPA is currently testing emissions from
candles and incense to generate data.
To support this  effort, the report collects
and presents two types of data: (1) mar-
ket information, and (2)  literature on the
potential  impacts of burning candles and
incense 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 the
sources and quantities of imported prod-
ucts. In addition, the  report summarizes
the results of a scientific literature  review.
It reports the findings in the scientific lit-
erature regarding  the emission rates of
the various contaminants generated when
burning candles and incense,  as well as
the potential health effects associated with
exposure to these contaminants.

Market Information
  Publicly  available  sources of data,
mostly from  the U.S. Bureau of the  Cen-
sus,  as well as private market studies
and trade literature were consulted to pro-
duce this summary of economic informa-
tion regarding the candle and incense
markets.  Dialog Information Service and
Internet searches were performed to iden-
tify market and related  information. The
U.S. Bureau of Census was contacted to
obtain  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 in
1997 of $968 million; industry estimates
put 1999  sales  at  $1.3  billion just  for
scented candles, and up to  $2.3  billion
for 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
  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.

  According to the  literature reviewed,
burning candles  containing  lead-core
wicks 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 candles
with  lead-core wicks,  indicated that  this
indoor air threshold was exceeded.  Re-
garding  candles  with non-lead  metal
cores,  the literature did not indicate  that
wicks made with zinc and tin emitted these
metals at concentrations that would raise
health 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  that
exceeded 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 by
blackening surfaces.  Although  soot  par-
ticles are very small and can  potentially
penetrate the deepest areas of the lungs,
studies regarding potential human  health
effects associated with soot from candles
were not found in the literature search.

  Large quantities of particulate  matter
are generated  when  burning incense.
Studies that examined the emissions of
specific contaminants from incense smoke
indicated that benzene and carbon mon-
oxide may  be  emitted at  concentrations
that could pose human health risks. Sev-
eral studies indicated links between ex-
posure to  incense smoke and  health
effects, such as cancer, asthma, and con-
tact  dermatitis.  Some  studies  indicated
possible mutagenic and genotoxic effects.

L Knight, A. Levin, and C. Mendenhall are with Eastern Research Group, Lexington, MA
Zhishi Quo is the EPA Project Officer (see below).
The complete report, entitled "Candles and Incense as Potential Sources of Indoor Air
  Pollution: Market Analysis and Literature Review," (Order No. PB2001-103 924; Cost:
  $27.00, subject to change) will be available only from
        National Technical Information Service
        5285 Port Royal Road
        Springfield, VA 22161
        Telephone: (703) 605-6000 (world wide)
                  (800) 553-6847 (U.S. only)
The EPA Project Officer can be contacted at
        Air Pollution Prevention and Control Division
        National Risk Management Research Laboratory
        U. S. Environmental Protection Agency
        Research Triangle Park, NC 27711-0001
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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