Particulate organic nitrates in eastern China: variation characteristics and effects of anthropogenic activities

Abstract

<p><strong>Abstract.</strong> Particulate organic nitrates (PONs) constitute a substantial fraction of secondary organic aerosols and have important effects on the reactive nitrogen budget and air quality. Laboratory studies have revealed the non-negligible influence of the interactions between anthropogenic pollutants and biogenic volatile organic compounds (BVOCs) on the formation of PONs. In this study, the contents of specific PONs, including monoterpene hydroxyl nitrate (MHN215), pinene keto nitrate (PKN229), limonene di-keto nitrate (LDKN247), oleic acid keto nitrate (OAKN359), oleic acid hydroxyl nitrate (OAHN361), and pinene sulfate organic nitrate (PSON295), in fine particulate matters at four rural and urban sites in eastern China were determined, and the variation characteristics of PONs and the impacts of human activities on PONs formation were investigated. The average concentration of PONs ranged from 116 to 548 ng m<sup>−3</sup> at these four sites. PONs were present in higher levels in summer than in other seasons, owing to the high emissions of precursors and intensive photochemical activities in this hottest season. Among the six species of PONs, MHN215 was dominant. In addition, the proportion of OAKN359 in PONs in urban areas was much higher than that in the rural site, indicating that OAKN359 primarily originated from anthropogenic activities. Slight diurnal differences existed in the concentration and secondary formation of specific PONs and varied with locations, seasons, and precursor VOCs. The measurement results showed that PONs in North China were clearly influenced by coal combustion and biomass burning, while meteorological conditions and biogenic emissions were the dominant contributing factors in the South China. Biomass burning significantly enhanced the formation of PONs due to the elevated concentrations of ozone and the released BVOCs. Sulfur dioxide (SO<sub>2</sub>) emitted from coal combustion was able to react rapidly with Criegee intermediates, the reaction products of BVOCs with ozone, to produce PONs at high rates, suggesting that there is a substantially greater role played by SO<sub>2</sub> in organic nitrate chemistry than has previously been assumed.</p>

Size Distribution and Secondary Formation of Particulate Organic Nitrates in Winter in a Coastal Area

“…Previous studies have confirmed that the abundance of PONs is significantly influenced by the physical and chemical characteristics of aerosols, mixing ratios of precursors and oxidants, meteorological parameters, and anthropogenic activities [13,15,16]. BVOCs, such as oleic acid, isoprene, sesquiterpene, and monoterpenes, are recognized as key precursors of PONs, and the formation of PONs varied largely depending upon BVOC species [16]. Elevated concentrations of both BVOCs and NO x contribute to an increase in PON production through the oxidation of BVOCs in the presence of NO x during photochemical processes, as noted in the studies by Lee and Li [3,17].…”

“…PONs form primarily as a result of the secondary oxidation of anthropogenic or biogenic volatile organic compounds (BVOCs) when exposed to radicals of other oxidizing agents in the presence of NO x [13,14]. Previous studies have confirmed that the abundance of PONs is significantly influenced by the physical and chemical characteristics of aerosols, mixing ratios of precursors and oxidants, meteorological parameters, and anthropogenic activities [13,15,16]. BVOCs, such as oleic acid, isoprene, sesquiterpene, and monoterpenes, are recognized as key precursors of PONs, and the formation of PONs varied largely depending upon BVOC species [16].…”

“…In general, PONs exhibit relatively high concentrations in summer, as intense photochemical activity and strong BVOC emissions during the hot season facilitate the secondary formation of PONs [30]. A comparative study on field observations over multiple locations and seasons was conducted in eastern China by Zhang et al [16], who reported that areas with high vegetation cover typically have greater PON concentrations because of the enhanced formation due to abundant BVOCs. Moreover, weather conditions, particularly ambient humidity, significantly influenced the PON's formation in South China [16].…”

“…A comparative study on field observations over multiple locations and seasons was conducted in eastern China by Zhang et al [16], who reported that areas with high vegetation cover typically have greater PON concentrations because of the enhanced formation due to abundant BVOCs. Moreover, weather conditions, particularly ambient humidity, significantly influenced the PON's formation in South China [16]. In addition, biomass burning and coal combustion promote the production of PONs, owing to the intensive emissions of NO x and VOCs, abundant oxidants, and acidic sulfate aerosols [16,31,32].…”

The trends in global, regional, and national incidence of pneumoconiosis caused by different etiologies: an analysis from the Global Burden of Disease Study 2017

“…Therefore the heterogeneous incidence pattern of pneumoconiosis depends mainly on the prevalence of risk factors in different regions. For example, the National Occupational Disease Report of 2016 indicated that 26,873 new cases of pneumoconiosis were recorded in China, of which 54.3% were coal workers' pneumoconiosis and 39.7% were silicosis [12]. Whereas Australia is one of the countries with the highest incidence rates of asbestos-related lung disease across the world [13,14].…”