Observations of the summertime atmospheric pollutants vertical distributions and the corresponding ozone production in Shanghai, China

Abstract

<p><strong>Abstract.</strong> Ground based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and lidar measurements were performed in Shanghai, China during May 2016 to investigate the summertime atmospheric pollutants vertical distribution. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO<sub>2</sub>) and formaldehyde (HCHO) concentrations were retrieved from MAX-DOAS measurement using the Heidelberg Profile (HeiPro) algorithm, while vertical distribution of ozone (O<sub>3</sub>) was obtained from an ozone lidar. Sensitivity study of the MAX-DOAS aerosol profile retrieval shows that the a priori aerosol profile shape has significant influences on the aerosol profile retrieval. Aerosol profiles retrieved from MAX-DOAS measurements with Gaussian a priori demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. MAX-DOAS measured tropospheric NO<sub>2</sub>Vertical Column Densities (VCDs) show a good agreement with OMI satellite observations with Pearson correlation coefficient (<i>R</i>) of 0.95. In addition, measurements of the O<sub>3</sub> vertical distribution indicate that the ozone productions do not only occur at surface level but also at higher altitudes (about 1.1 km). Planetary boundary layer (PBL) height, horizontal and vertical wind fields information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground and upper altitudes are not directly related to horizontal and vertical transportations. Similar patterns of O<sub>3</sub> and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near to the surface and at higher altitudes are mainly influenced by the abundance of volatile organic compounds (VOCs) in the lower troposphere.</p>

Stereoscopic Monitoring: A Promising Strategy to Advance Diagnostic and Prediction of Air Pollution

“…Similar improvements are found for other satellite products and over other regions (Liu et al, 2016). Our recent investigation (Su et al, 2020;Xing et al, 2017) demonstrates that using ground measured HCHO profiles as a priori in the calculation of AMF can remarkably improve the accuracy of retrieved HCHO column. The results indicate also that the improvement in the estimation of retrievals of HCHO is attributed largely to the updated prior and AMF (60%), while the influence of SCD retrievals is relatively minor (0.15%) (Su et al, 2020).…”

PM2.5 Pollution Modulates Wintertime Urban Heat Island Intensity in the Beijing‐Tianjin‐Hebei Megalopolis, China

“…Fine particulate matter, that is, particulate matter with aerodynamic diameter equal to or less than 2.5 μm (PM 2.5 ), is considered as one of the most important air pollutants degrading air quality (Kim et al, ; Pongpiachan et al, ; Tiwari et al, ; Xing et al, ; Zheng, Xu, et al, ). It endangers the urban environment and the health of residents due to its complicated composition and properties (Gu et al, ; Jiang et al, ; Liang et al, ; Turpin & Huntzikcker, ; Wang, Gao, et al, ; Wang, Li, ; Zhao et al, ).…”

Source Apportionment of Regional Ozone Pollution Observed at Mount Tai, North China: Application of Lagrangian Photochemical Trajectory Model and Implications for Control Policy

“…For NMVOCs, the regional background concentrations were set using the data obtained from Mount Tai (Zhu et al., 2017). For other pollutants, the regional background concentrations in the NCP were determined using the observational data at Mount Tai, and those in other regions were obtained from previous studies (Wang, Xu, et al., 2017; Xing et al., 2017; Xu et al., 2020). Model simulations were then iteratively performed according to (E1) to make the model‐simulated O 3 and related species be more reasonably consistent with the in‐situ measurement data at Mount Tai: where CI i and CE i represent the initial and final concentrations of the target pollutant in the i th simulation, respectively, and C obs refers to the observed concentration of the target pollutant.…”