Characterization of fine particle emissions from burning church candles

A series of source tests were conducted on the combustion of paraffin and b eeswax candles. An enclosed chamber sampling system was utilized, and fine particle samples were collected on both quartz fiber and Teflon filters. El ectronic particle sizing was performed using an optical particle counter an d a differential mobility analyzer. Filter samples were weighed to determin e fine particle mass emission rates and then analyzed for elemental carbon and organic carbon by thermal evolution and combustion analysis and for org anic chemical composition by GC/MS. Three modes of candle burning were obse rved with very different emission profiles: a "normal burning" mode charact erized by low mass emission rates and particles smaller than 100 nm in diam eter; a "sooting" behavior with high emission rates of predominantly elemen tal carbon particles; and a "smoldering" phase upon candle extinction durin g which most of the mass emissions occurred as white particles having diame ters between 400 and 800 nm. The majority of emissions were organic compoun ds including alkanes, alkenes, alkanoic acids, wax esters, cyclohexylalkane s, and alkanals. Analysis of the unburned waxes revealed that while some of these compounds were thermally altered products of the unburned wax, many others were unaltered candle components emitted by direct volatilization. T hus, possible chemical tracers for candle burning may be easily identified by analyzing unburned wax material. The information provided in this study, in conjunction with future ambient indoor air sampling programs and recept or-oriented chemical mass balance techniques, can be used to determine the relative importance of candle burning to indoor soiling problems.