Investigations of temporal and spatial distribution of precursors SO<sub>2</sub> and NO<sub>2</sub> vertical columns in the North China Plain using mobile DOAS

Abstract

Abstract. Recently, Chinese cities have suffered severe events of haze air pollution, particularly in the North China Plain (NCP). Investigating the temporal and spatial distribution of pollutants, emissions, and pollution transport is necessary to better understand the effect of various sources on air quality. We report on mobile differential optical absorption spectroscopy (mobile DOAS) observations of precursors SO 2 and NO 2 vertical columns in the NCP in the summer of 2013 (from 11 June to 7 July) in this study. The different temporal and spatial distributions of SO 2 and NO 2 vertical column density (VCD) over this area are characterized under various wind fields. The results show that transport from the southern NCP strongly affects air quality in Beijing, and the transport route, particularly SO 2 transport on the route of Shijiazhuang-Baoding-Beijing, is identified. In addition, the major contributors to SO 2 along the route of ShijiazhuangBaoding-Beijing are elevated sources compared to low area sources for the route of Dezhou-Cangzhou-Tianjin-Beijing; this is found using the interrelated analysis between in situ and mobile DOAS observations during the measurement periods. Furthermore, the discussions on hot spots near the city of JiNan show that average observed width of polluted air mass is 11.83 and 17.23 km associated with air mass diffusion, which is approximately 60 km away from emission sources based on geometrical estimation. Finally, a reasonable agreement exists between the Ozone Monitoring Instrument (OMI) and mobile DOAS observations, with a correlation coefficient (R 2 ) of 0.65 for NO 2 VCDs. Both datasets also have a similar spatial pattern. The fitted slope of 0.55 is significantly less than unity, which can reflect the contamination of local sources, and OMI observations are needed to improve the sensitivities to the near-surface emission sources through improvements of the retrieval algorithm or the resolution of satellites.

A proxy for atmospheric daytime gaseous sulfuric acid concentration in urban Beijing

“…Beijing is a location with typical CS values (e.g., 0.01-0.24 s −1 in the 5 %-95 % percentiles in this study) that are 10-100 times higher (Herrmann et al, 2014;Wu et al, 2007;Xiao et al, 2015;Yue et al, 2009;Zhang et al, 2011) and typical SO 2 concentrations that are 1-10 times higher (M. Wu et al, 2018) than those in Europe and North America (Dunn et al, 2004;Mikkonen et al, 2011), yet measured gaseous sulfuric acid concentrations are relatively similar in these environments Smith et al, 2008;Zheng et al, 2011). Whether previous proxies developed for European and North American sites work in Beijing remains to be tested.…”

Validation of MAX-DOAS retrievals of aerosol extinction, SO<sub>2</sub>, and NO<sub>2</sub> through comparison with lidar, sun photometer, active DOAS, and aircraft measurements in the Athabasca oil sands region

“…There are also relatively few published comparisons of MAX-DOAS aerosol optical depths (AODs) with lidar AODs (Irie et al, 2008(Irie et al, , 2015. Relatively few studies have focused on MAX-DOAS measurements of anthropogenic SO 2 Jin et al, 2016;Wang et al, , 2017Wu et al, 2018Wu et al, , 2013. Most studies that present MAX-DOAS vertical profile retrievals compare them to trace gas VCDs or near-surface measurements from in situ or LP-DOAS instruments.…”

Effects of AIR pollution on cardiopuLmonary disEaSe in urban and peri-urban reSidents in Beijing: protocol for the AIRLESS study

“…AIRLESS focuses on the adverse health effects of air pollution in Beijing, China, a metropolitan city characterized by a high population density and poor air quality. Owing to rapid urbanization, Beijing also manifests a unique difference in health status (Li et al, 2016) and air pollution settings between urban and peri-urban areas, both in concentrations and species (Zhao et al, 2009;Wu et al, 2018;Xu et al, 2011), which may, in part, be responsible for different health responses of local residents. Therefore, the results from the AIRLESS project will be a valuable record and opportunity to study the contrast of air pollution by location and as a consequence impact on human health within a major city with high concentrations of air pollution.…”