Model Simulations of PAHs in Northeast Asia

Abstract

The emissions, concentrations, and transboundary transport of particulate polycyclic aromatic hydrocarbons (PAHs) in Northeast Asia were investigated using Regional Emission inventory in Asia for Persistent Organic Pollutants (REAS-POP) and the chemical transport model (Regional Air Quality Model for POPs version, RAQM-POP). The nine particulate PAH concentrations simulated agreed well with the measured concentrations, and the results firmly established the efficacy of REAS/RAQM-POP. The estimated annual emission of the nine PAHs in 2005 in Northeast Asia was approximately 10.5 Gg year⁻¹, and the emission from China (9.6 Gg year⁻¹) accounted for 92% of emissions in Northeast Asia. The largest component of these emissions was four-ring PAHs, followed by five- and six-ring congeners. It was found that the PAH concentrations in Beijing, which were emitted predominantly from domestic coal, domestic biofuel, and coke production, were approximately two orders of magnitude greater than those at Noto (in Japan, leeward region). In Noto, the PAH concentrations showed seasonal variations with highs from the winter to spring and lows in the summer. These seasonal variations were due to seasonal variations in emissions from China, as well as transboundary transport across the Asian continent. Also, in the summer, the contribution from domestic sources such as on-road automobiles showed a relative increase.