Chemical composition of fine particles from incense burning in a large environmental chamber

This study is aimed to characterize the major chemical compositions of PM2.5 from incense burning in a large environmental chamber. Chemical analyses, including X-ray fluorescence for elemental species, ion chromatography for water soluble inorganic species (chloride, nitrate, sulfate, sodium, potassium, ammonium) and thermal/optical reflectance analysis for carbon species were carried out for combustion of three incense categories (traditional, aromatic and church incense). The average concentrations from incense burning ranged from 139.8 to 4414.7 μg m−3 for organic carbon (OC), and from 22.8 to 74.0 μg m−3 for elemental carbon (EC), respectively. The average OC and EC concentrations in PM2.5 of three incense categories were in the order of church incense>traditional incense>aromatic incense. OC/EC ratios ranged from 7.0 to 39.1 for the traditional incense, with an average of 21.7; from 3.2 to 11.9 for the aromatic incense, with an average of 7.7. The concentrations of Cl−, SO42−, Na+ and K+ were highly variable. On average, the inorganic ion concentration sequence was traditional incense>church incense>aromatic incense. The profiles for elements were dominated by Na, Cl and K. In general, the major components in PM2.5 fraction from incense burning are OC (especially OC2, OC3 and OC4), EC and K.