Emissions of Condensable Organic Aerosols from Stationary Combustion Sources over Japan

Treatment of condensable particulate matter (CPM) is key for accurate simulation of atmospheric particulate matter (PM), because conventional stationary combustion source emission surveys do not measure CPM in many countries. This study updates previously estimated CPM emissions from stationary combustion sources in Japan by considering the relationship between the CPM fraction and filterable PM (FPM) concentrations for individual sources rather than using a uniform CPM/FPM ratio for all sources. As a result, the total emissions ratio of condensable organic aerosol (OA) and filterable PM_2.5 ( ${\text{OA}}_{\text{CPM}}∕\text{PM}{2.5}_{\text{FPM}}$ ) from stationary combustion sources, based on this update, changes from ~2.0 to 0.20, and the estimated concentrations of condensable OA, averaged over winter and over summer, changes from up to 3 microg m^-3 to up to 0.2 microg m^-3. The normalized mean bias for concentration of the simulated organic carbon (OC) in winter changes from -78% ~ -9% to -83% ~ -28%), although the proportion of modern carbon in total carbon is better estimated. The CPM contribution is likely to be overestimated when the source-dependent relationship between the CPM/FPM ratio and FPM concentration is not considered. Thus, accurate knowledge of the CPM/FPM ratio, particularly for sources with high FPM concentrations, is critical to improve CPM emission estimation.