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

Abstract

Abstract. Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) and lidar measurements were performed in Shanghai, China, during May 2016 to investigate the vertical distribution of summertime atmospheric pollutants. In this study, vertical profiles of aerosol extinction coefficient, nitrogen dioxide (NO 2 ) and formaldehyde (HCHO) concentrations were retrieved from MAX-DOAS measurements using the Heidelberg Profile (HEIPRO) algorithm, while vertical distribution of ozone (O 3 ) 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 profile demonstrate the best agreements with simultaneous lidar measurements and vehicle-based tethered-balloon observations among all a priori aerosol profiles. Tropospheric NO 2 vertical column densities (VCDs) measured with MAX-DOAS show a good agreement with OMI satellite observations with a Pearson correlation coefficient (R) of 0.95. In addition, measurements of the O 3 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 and horizontal and vertical wind field information were integrated to discuss the ozone formation at upper altitudes. The results reveal that enhanced ozone concentrations at ground level and upper altitudes are not directly related to horizontal and vertical transportation. Similar patterns of O 3 and HCHO vertical distributions were observed during this campaign, which implies that the ozone productions near the surface and at higher alPublished by Copernicus Publications on behalf of the European Geosciences Union.

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

“…The effect of atmospheric pollution on urban climate is mainly determined in both direct and indirect ways, known as aerosol-radiation interaction and aerosol-cloud interaction, respectively. First, particles exert direct effects on the climate by scattering or absorbing solar radiation Gu et al, 2006Gu et al, , 2010Huang et al, 2018;Li et al, 2017;Wu et al, 2017;Zhang et al, 2010). Second, they modify the optical properties of clouds, cloud distributions in the form of cloud condensation nuclei, cloud fraction, and its lifetime, thus influencing the climate indirectly Li et al, 2016;Liao et al, 2015;Small et al, 2011;Zhao et al, 2017).…”

“…It endangers the urban environment and the health of residents due to its complicated composition and properties Jiang et al, 2015;Liang et al, 2015;Turpin & Huntzikcker, 2006;. The relationship between air pollutants and the urban heat island (UHI, i.e., elevated urban air/surface temperatures compared to those in rural surroundings, most prominently present during nighttime) has also attracted attention from the scientific community (Cao et al, 2016;Crutzen, 2004;Jonsson et al, 2004;Wu et al, 2017;Zheng, Ren, et al, 2018). A detailed understanding of the relationship between PM 2.5 and the UHI effect is of great significance for adapting urban climate change, urban planning, and the development of urban sustainable ecosystem (Cao et al, 2016;Oke et al, 2017;Thornes, 2001;Roth, 2010;Velasco & Roth, 2012;Yoshikado & Tsuchida, 1996;Zhao et al, 2014;Zhou et al, 2008).…”

“…Shades from tall buildings in the city center are primarily responsible for the daytime urban cool island (Yang, et al, 2017), while high-concentration aerosols in the urban boundary layer also may cause an additional cooling radiation effect in the daytime (Chen et al, 2003). Wu et al (2014Wu et al ( , 2017 suggested that the PM 2.5 concentration in the atmosphere had a weakening effect on the UHII, but such influence was limited only to the lowest 500-1,000 m. In addition, Deng et al (2002) suggested that the UHI effect primarily arised from the effects of atmospheric warming by anthropogenic heat and the changes in the underlying urban surface properties, but the cooling effect due to PM 2.5 also cannot be neglected.…”

Ship-based MAX-DOAS measurements of tropospheric NO<sub>2</sub>, SO<sub>2</sub>, and HCHO distribution along the Yangtze River

“…The local overpass time of OMI is between 13:40 and 13:50 (local time) on the ascending node. In this study, USTC's OMI tropospheric NO 2 product is used, which is developed based on OMI's primary product and has proven to be more suitable for the atmospheric conditions in China (Liu et al, 2016;Xing et al, 2017;Su et al, 2017). Slant column densities (SCDs) of NO 2 are retrieved by applying the DOAS fit to OMI spectra (data source: OMI Level 1B VIS Global Radiances Data product (OML1BRVG), https://disc.gsfc.nasa.…”

Aerosol optical characteristics and their vertical distributions under enhanced haze pollution events: effect of the regional transport of different aerosol types over eastern China

“…Many studies have been conducted on the aerosol optical properties and their variations in the cities of the YRD, such as Shanghai, Nanjing, Lin'an, and Taihu Pan et al, 2010;He et al, 2012;Ding et al, 2013;Liu et al, 2015;Xing et al, 2017). Particularly in Hangzhou, the capital city of Zhejiang province, some researchers have focused on determining the seasonal variation of aerosol properties, chemical compositions, and particulate matter (PM) concentrations (Qi, 2016;Ming et al, 2017;Xiao et al, 2011), or single-case analyses on features of a particular pollution process Fu et al, 2014;.…”