Significant impacts of anthropogenic activities on monoterpene and oleic acid-derived particulate organic nitrates in the North China Plain

Abstract

Particulate organic nitrates (PONs) are among the major components of organic aerosols and affect the reactive nitrogen budget and ozone formation on regional scale. Previous laboratory and field studies have shown some preliminary evidence for the effects of anthropogenic activities on the formation of PONs. In this study, the concentrations of six kinds of PONs in rural and urban areas in the North China Plain were determined, and the seasonal and diurnal difference and effects of anthropogenic activities on their formation were investigated. The average total concentration of PONs was in the range of 113– 415 ng m−3, contributing 0.7% –2.8% to organic matter during the observation periods. Distinct seasonal variation was observed, with higher concentrations appearing in summer than in winter due to the large emissions of precursor BVOCs and intensive photochemical activities in the hot season. The concentration and formation of some specific PONs exhibited diurnal differences in summer, while the differences were small in other seasons. The observations showed that PONs in the North China Plain were significantly influenced by open biomass burning and coal combustion. The formation of PONs was enhanced by increased BVOCs released from biomass burning and consequently elevated levels of ozone. Industrial and residential coal combustion contributed to the increased concentrations of PONs by providing related reactants and interfaces and facilitating the formation rates of PONs.