Characterization of organic particles from incense burning using an aerodyne high-resolution time-of-flight aerosol mass spectrometer

Incense burning is a common ritual in Asian communities both indoors in residential homes and outdoors in temple premises. Organic particles from burning of incense sticks, incense coils, and mosquito coils after extensive dilution (>1000x) were characterized by the Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The obtained mass spectra in general resemble those reported for biomass burning aerosols. Ion peaks with m/z values higher than 100 accounted for 15%-25% of the organic signals in the unit-mass-resolution (UMR) mass spectra. In the high-resolution (HR) mass spectra, the ion peaks at m/z 60 and 73 are found to be related to the sugar anhydrides as in particles from other biomass burning processes. In addition, the ion peaks at m/z 107, 121, 137, 151, 167, and 181, some of which (e.g., m/z 137 and 167) have been observed in particles from biomass burning but not yet assigned, were assigned to lignin-related components. Elemental analysis from the HR data reveals that a large portion of particulate organics from incense burning are oxygenated (O/C between 0.3 and 0.5) and unsaturated (and/or cyclic) in nature. Results from this study also highlight that mass spectra from HR-ToF-AMS measurements concerning primary emissions such as incense burning contain very useful information in the high m/z (>100) region about the chemical characteristics of those primary organic particles. Copyright © American Association for Aerosol Research.