Identification of NO2 and SO2 Pollution Hotspots and Sources in Jiangsu Province of China

Abstract

Nitrogen dioxide (NO2) and sulfur dioxide (SO2) are important atmospheric trace gases for determining air quality, human health, climate change, and ecological conditions both regionally and globally. In this study, the Ozone Monitoring Instrument (OMI), total column nitrogen dioxide (NO2), and sulfur dioxide (SO2) were used from 2005 to 2020 to identify pollution hotspots and potential source areas responsible for air pollution in Jiangsu Province. The study investigated the spatiotemporal distribution and variability of NO2 and SO2, the SO2/NO2 ratio, and their trends, and potential source contribution function (PSCF) analysis was performed to identify potential source areas. The spatial distributions showed higher values (>0.60 DU) of annual mean NO2 and SO2 for most cities of Jiangsu Province except for Yancheng City (<0.50 DU). The seasonal analyses showed the highest NO2 and SO2 in winter, followed by spring, autumn, and summer. Coal-fire-based room heating and stable meteorological conditions during the cold season may cause higher NO2 and SO2 in winter. Notably, the occurrence frequency of NO2 and SO2 of >1.2 was highest in winter, which varied between 9.14~32.46% for NO2 and 7.84~21.67% for SO2, indicating a high level of pollution across Jiangsu Province. The high SO2/NO2 ratio (>0.60) indicated that industry is the dominant source, with significant annual and seasonal variations. Trends in NO2 and SO2 were calculated for 2005–2020, 2006–2010 (when China introduced strict air pollution control policies during the 11th Five Year Plan (FYP)), 2011–2015 (during the 12th FYP), and 2013–2017 (the Action Plan of Air Pollution Prevention and Control (APPC-AC)). Annually, decreasing trends in NO2 were more prominent during the 12th FYP period (2011–2015: −0.024~−0.052 DU/year) than in the APPC-AC period (2013–2017: −0.007~−0.043 DU/year) and 2005–2020 (−0.002 to −0.012 DU/year). However, no prevention and control policies for NO2 were included during the 11th FYP period (2006–2010), resulting in an increasing trend in NO2 (0.015 to 0.031) observed throughout the study area. Furthermore, the implementation of China’s strict air pollution control policies caused a larger decrease in SO2 (per year) during the 12th FYP period (−0.002~−0.075 DU/year) than in the 11th FYP period (−0.014~−0.071 DU/year), the APPC-AC period (−0.007~−0.043 DU/year), and 2005–2020 (−0.015~−0.032 DU/year). PSCF analysis indicated that the air quality of Jiangsu Province is mainly influenced by local pollution sources.

Impact of COVID-19 lockdown on PM concentrations in an Italian Northern City: A year-by-year assessment

“…Considering the variety of pollution sources and local environmental and meteorological situations, the reasons for this are not easy to explain, and a precise characterization of the main pollutants’ sources is needed to understand these dynamics. For example, NO 2 is usually produced from anthropogenic emissions such as industrial burning of fossil fuels like coal, oil and gas and vehicle exhaust [ 25 ]. A majority of the Particulate Matter, on the other hand, is formed from secondary formation, as PM is a generic measure that includes lots of different types of dusts, including soil residuals, sea salt, car pneumatics debris and all types of combustion processes residuals [ 26 ], including those used in old house heating systems.…”

Spatiotemporal characterization of aerosols and trace gases over the Yangtze River Delta region, China: impact of trans-boundary pollution and meteorology

“…SO 2 is mainly produced from fossil fuel burning for domestic heating, power plants emissions, oil refineries, and metal smelters [ 40 ]. Across the four cities, the highest annual mean SO 2 concentration (10 µg/m 3 ) was observed in Nanjing during 2019.…”

“…Overall, these results show that Hefei (38.4 µg/m 3 ) is the most polluted city of the YRD region compared to the other cities, however, all the cities meet the NAAQS and WHO air quality standards based on annual mean NO 2 concentrations from 2018 to 2021. SO 2 is mainly produced from fossil fuel burning for domestic heating, power plants emissions, oil refineries, and metal smelters [40]. Across the four cities, the highest annual mean SO 2 concentration (10 µg/m 3 ) was observed in Nanjing during 2019.…”

Temporal Variations and Spatial Distribution of Air Pollutants in Shaoxing, a City in Yangtze Delta, China Based on Mobile Monitoring Using a Sensor Package

“…Shaoxing City is dominated by light industry and is located in the central area of Zhejiang Province, which is not susceptible to emissions from marine vessels, so the concentration of SO 2 is not high. The SO 2 /NO 2 ratio is an indicator used to determine whether air pollutants come from stationary sources (e.g., industrial emissions) or mobile sources (e.g., traffic emissions) [44], with high ratios (>0.60) indicating significant contributions from stationary sources and low ratios (0.04 to 0.12) indicating significant contributions from mobile sources [45,46]. The SO 2 /NO 2 ratios were 0.05, 0.10, 0.21 and 0.07 for the four seasonal mobile monitoring periods, indicating that the measured pollutants were mainly from traffic.…”