Influence\nof Candle\nEmissions on Monoterpene Oxidation\nChemistry and Secondary Organic Aerosol

Candle burning is a considerable\ncontributor to indoor\npollutants,\nwhile secondary organic aerosols (SOA) from monoterpene ozonolysis\nrepresent another type. However, knowledge of the interactions of\ndifferent indoor pollutants is limited. We investigated physicochemical\nproperties of SOA generated from typical indoor chemistry of the O<sub>3</sub>/α-pinene reaction with and without the presence of\nparticles and gases from a burning candle. Ozonolysis of α-pinene\nin the presence of candle gaseous emissions yielded a considerably\nlower particle number, larger particle sizes, and lower particle oxygen-to-carbon\nratio compared with experiments without candle emissions. More nitrogen-containing\norganic compounds were observed in the aerosol phase with candle emissions.\nFurthermore, concentrations of some typical particle-phase products\nfrom the O<sub>3</sub>/α-pinene reaction (i.e., terebic acid, <i>cis</i>-pinic acid, and 3-methyl-1,2,3-butanetricarboxylic acid)\nwere less abundant in the presence of candle emissions. The predicted\nvolatility of particulate organic compounds was higher in experiments\nwith candle emissions. The study demonstrates that candle burning\ncan affect the chemical and physical properties of particles formed\nfrom other sources (e.g., α-pinene ozonolysis) by affecting\ngas-phase chemistry and gas-particle partitioning.