The science of Candles
Candle Research Studies
Candle Emission Studies
A series of research studies on candle emissions have been carried out at the Beyreuth Institute for Environmental Investigations (Okometric GmbH) in Germany, which has developed a candle-specific laboratory burn chamber. These studies, which began in 1994, have been funded by various candle associations and consortiums.
2007 -- Analysis of Emissions from Paraffin, Soy, Palm, Beeswax and Stearin Candles.
An analysis of paraffin, soy, palm, stearin and beeswax candles for emissions of dioxins and furans, polycyclic aromatic hydrocarbons, short-chain aldehydes and more than 270 volatile organic compounds. The study found all of the waxes burned in the same manner, creating comparable emissions, and posing no discernible risks to human health or indoor air quality.
2007 Okometric Study Summary (pdf)
1999 -- Analysis of Emissions from Heavily Fragranced Candles
This study is a follow-on to a 1997 study of scented candles(see below). Researchers analyzed emissions for dioxins and furans, polycyclic aromatic hydrocarbons, and short-chain aldehydes, using multiple fragrance groupings, at a very high fragrance load. The study found higher emissions levels for the heavily fragranced candles, but they still remained below any level of concern.
German language (courtesy European Candle Association): OEKOMETRIC 1999 (pdf)
English translation (courtesy National Candle Association): 1999 Okometric Study (pdf)
1997 -- Analysis of Emissions from Fragranced Candles
This study investigated the emissions from scented paraffin candles for dioxins and furans, polycyclic aromatic hydrocarbons and short-chain aldehydes. The study found that emissions from scented candles ”prove no significant danger potential to humans. A worst-case scenarios of burning 30 candles simultaneously for 4 hours in a residential-size room without any ventilation/air exchange also found emission values to be of no concern.
German language (Parts 1 and 2). Courtesy European Candle Association: OEKOMETRIC 1997 Duftkerzen 1teUntersuchung Teil 1 (pdf)
OEKOMETRIC 1997 Duftkerzen 1teUntersuchung Teil 2 (pdf)
English translation (combined Parts 1 & 2). Courtesy National Candle Association:
Okometric 97 Study (pdf)
1997 -- Comparison of Raw Materials and Emission Contaminants of Colored Paraffin, Beeswax and Stearin Candles
This study evaluated the raw materials and emissions of colored (lacquered) candles for dioxins and furans, polycyclic aromatic hydrocarbons and short-chained aldehydes. It found that emission levels generally paralleled concentrations found in ambient air and posed no health risks. Even when 30 candles were simultaneously burned in a small room without ventilation, the emission compound levels were below 1 percent of workplace limit values.
Published as Levels of Selected Organic Compounds in Materials for Candle Production and Human Exposure to Candle Emission. Lau, C.; Fiedler, H.; Hutzinger O.; Schwind, K-H.; Hosseinpour, J.; Chemosphere, Vol. 34, Nos 5-7; 1623-1630 (1997)
Courtesy European Candle Association:
Lau-et-al Chemosphere34_1997 (pdf)
1994 – Analysis and Risk Assessment of Raw Materials and Emissions
from Paraffin, Beeswax and Stearin Candles.
This study analyzed the raw materials and emissions from paraffin, beeswax and stearin candles for the presence of dioxins and furans, polycyclic aromatic hydrocarbons and short-chained aldehydes. The study concluded that the emissions from all candle types were “toxicologically harmless” and without any significant difference in chemical composition.
Published as: Bestimmung und Bewertung der Emissionen von PCDD/PCDF, PAK und kurzkettigen Aldehyden in den Brenngasen von Kerzen. Schwind K.-H., Hosseinpour J., Fiedler H, Lau Ch., Hutzinger O. UWSF – Z. Umweltchem. Ökotox., 6 (5), 243 – 246 (1994)
German language. Courtesy European Candle Association:
Schwind et al 1994 Brandgase von Kerzen (pdf)
English translation (courtesy National Candle Association):
Translation Schwind et al 1994 (pdf)
General Candle Studies
Characterization of Fine Particle Emissions from Burning Church Candles.
Fine, P.; Cass, G.; Simoneit, B. R.T.;
Environmental Science & Technology Vol. 33, No. 14: 1999
Summary: Chamber testing of paraffin and beeswax candles was conducted to determine fine particle emission rates and their carbon composition. It describes three distinct burning modes: "normal," with low emission rates; "sooting," with high emission rates; and "smoldering" (post-extinguished), with the greatest amount of soot emissions. Generally the "sooting" candle emission rate was found to be an order of magnitude greater than for the "normal" candles, with the “smoldering” conditions to be approximately two orders of magnitude greater.
Purchase at http://pubs.acs.org/doi/abs/10.1021/es981039v
Characterization of Candle Flames
Hamins, A; Bundy, M; Dillon S.
Journal of Fire Protection Engineering; Vol. 15, No. 4; November 2005.
Summary: Research on the burning behavior and properties of candles to assist fire officials in investigating accidental candle fires. Paraffin candles were burned in laboratory conditions to measure the mass, burning rate, regression rate, flame height and heat flux of common candles. In addition, several simulations were performed to model the burning rate and heat flux profile of a candle flame for comparison to the flame height and heat flux data obtained in the lab experiments.
http://fire.nist.gov/bfrlpubs/fire05/PDF/f05141.pdf (Free Access)
The Quality Candle
Michael Matthai and Norbert Petereit
SOFW Journal, 2004. Vol. 130; No. 10
Summary: A technical article providing an overview of the raw materials used in candles, the chemical structure of various candle waxes, and an illustrated explanation of the combustion process in the candle flame. Also includes information relating to various European and German standards for candles.
German version: Die Qualitaetskerze (pdf)
English version: Matthaei Petereit 2004 The Quality Candle (pdf)