[Analysis of Peroxyacetyl Nitrate and Ozone During a Typical Photochemical Pollution Process at the Panyu Atmospheric...

The typical photochemical pollution process in Guangzhou was analyzed from 2010 to 2016 by observing photochemical pollutants (ozone (O₃), peroxyacetyl nitrate (PAN), volatile organic compounds (VOCs), nitrogen dioxide (NO₂), and nitric oxide (NO)) and meteorological factors at the Guangzhou Panyu Atmospheric Composition Station (GPACS). The results showed that during this photochemical pollution process, the average O₃ and PAN concentrations were relatively high:O_3,max 1 h concentration was 140.6×10^-9 and PAN_max 1 h concentration was 4.7×10^-9. The average concentration of NO was low, which had little effect on O₃ titration and PAN elimination. The high NO₂ concentration, strong radiation, and low wind speed all led to the formulation and accumulation of O₃ and PAN. The linear relationship between O₃ and PAN (R²=0.55) was affected by the fact that their precursor VOCs were not similar. Ethene, propane, isoprene, and toluene had a large influence in PAN formation, while isoprene, 1,3,5-trimethylbenzene, propene, m,p-xylene, and toluene had a large influence on O₃ formation potential. When evaluating PA concentration, we found that its daily average concentration ranged from 0.11×10^-12 to 0.16×10^-12, which were higher than many places around the world, indicating that this photochemical process was relatively intensive.