Ants As shown in Figures 3 and four, the highest concentrations of PM2.five and PM10 have been recorded at industrial web sites along with the lowest levels have been recorded at mountainous web pages, which indicated high pollution of particulate matter at industrial sites. A preceding fiveyear study in S Paulo state, Brazil, also discovered that PM10 concentrations have been greater in industrial locations than in urban regions [10]. SO2 concentrations showed a clear gradient at 4 distinct observed regions ( Figure 3c), suggesting that industrial manufacturing processes are a vital source of Enclomiphene citrate atmospheric SO2 in Nanchang. Additionally, SO2 concentrations rapidly decreased from 27.04 /m3 in December 2017 to 19.17 /m3 in February 2018, plus the same pattern was observed for all air pollutants (Figure three). This phenomenon might be attributed to the culmination of ten air pollution prevention and control measures throughout the winter of 2017018. NOx (NO + NO2 ) concentrations were greater at urban sites than at counties, industrial, and mountainous internet sites (Figure 3d ), suggesting that automobile exhaust may be the dominant supply of NOx. A large quantity of studies have also reported that vehicle exhaust is an important source of urban NOx [203]. CO concentrations had been greater at urban and industrial internet sites than at county and mountainous web pages (Figure 3g,h), which might be associated towards the residential population and site visitors emissions [23]. No apparent regional patterns were observed for O3 concentrations at all web pages (Figure 3h). In contrast to major gas-phase air pollutants, O3 is produced by photochemical reactions, which are primarily impacted by sunlight intensity and ratios of VOCs to NOx [24]. The wide variations in main air pollutants at different regional sites in Nanchang indicated that, on the one hand, our zoning is affordable, and on the other hand, measures for reducing air pollution must be specified according to districts. three.2. Seasonal Variations of Air Pollutants Overall, all the air pollutants showed distinct seasonal patterns (Figure 4). From April 2017 to December 2019, PM2.5 , PM10 , CO, and NOx exhibited the lowest and highest concentrations in summer (June, July, and August) and winter (December, January, and February), respectively, at urban, industrial, county, and mountainous internet sites. The seasonal variations of PM2.five , PM10 , CO, and NOx concentrations were mainly affected by the atmospheric boundary layer height, meteorological parameters, and emission intensity. Studies in Shanghai [25], Beijing [26], and the north China Plain [27] have discovered that higher levels of fine particulate matter were usually accompanied by low atmospheric boundary layer height and wind speed. Together with the lowest atmospheric boundary layer height and wind speed (Figure 2b), the winter season promotes the accumulation of PM2.five and PM10 in Nanchang, top to their highest levels. Moreover, precipitation is drastically greater in summer season than in winter (Figure 2a); the abundant rainfall throughout summer season can remove a lot more particulate matter as compared with that in winter [28,29]. Regarding CO and NOx, in addition to the influences of atmospheric boundary layer height and meteorological parameters, emission intensity also needs to be deemed since heating needs are greater in winter, which implies greater CO and NOx emissions [28,30]. No constant seasonal pattern was observed for SO2 (Figure 4c) at urban, industrial, county,Atmosphere 2021, 12,six ofand mountainous web pages, which might be attributable to the s.
