Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

<div>(a) Regional ozone-NO<sub><i>x</i></sub>-VOC sensitivity characteristics in summer in the NCP. The contours are the tropospheric O<sub>3</sub> column concentrations (units: DU). (b) Comparison of FNR in major cities for two phases (2005–2011 and 2012–2016) from remote sensing. FNR is defined as the ratio of tropospheric HCHO column concentration to tropospheric NO<sub>2</sub> column concentration.</div>

Advances in Meteorology

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Figure 7

Figure 7: Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China 