Impacts of meteorology and emissions on surface ozone increases over Central Eastern China between 2003 and 2015

Abstract

<p><strong>Abstract.</strong> Recent studies have shown that surface ozone (O<sub>3</sub>) concentrations over Central Eastern China (CEC) have increased significantly during the past decade. We quantified the effects of changes in meteorological conditions and O<sub>3</sub> precursor emissions on surface O<sub>3</sub> levels over CEC between July 2003 and July 2015 using the GEOS-Chem model. The simulated monthly mean maximum daily 8-h average O<sub>3</sub> concentration (MDA8 O<sub>3</sub>) in July increased by approximately 13.6 %, from 65.5 ± 7.9 ppbv (2003) to 74.4 ± 8.7 ppbv (2015), comparable to the observed results. The change in meteorology led to an increase of MDA8 O<sub>3</sub> of 5.8 ± 3.9 ppbv over the central part of CEC, in contrast to a decrease of about −0.8 ± 3.5 ppbv over the eastern part of the region. In comparison, the MDA8 O<sub>3</sub> over the central and eastern parts of CEC increased by 3.5 ± 1.4 ppbv and 5.6 ± 1.8 ppbv due to the increased emissions. The increase in regional averaged O<sub>3</sub> resulting from the emission increase (4.0 ± 1.9 ppbv) was higher than that caused by meteorological changes (3.1 ± 4.9 ppbv) relative to the 2003 standard simulation, while the regions with larger O<sub>3</sub> increases showed a higher sensitivity to meteorological conditions than to emission changes. Sensitivity tests indicate that increased levels of anthropogenic non-methane volatile organic compounds (NMVOCs) dominate the O<sub>3</sub> increase over the eastern part of CEC, and anthropogenic nitrogen oxides (NO<sub><i>x</i></sub>) mainly increase O<sub>3</sub> concentrations over the central and western parts, while decrease O<sub>3</sub> in a few urban areas in the eastern part. Process analysis showed that net photochemical production and meteorological conditions (transport in particular) are two important factors that influence O<sub>3</sub> levels over the CEC. The results of this study suggest a need to further assess the effectiveness of control strategies for O<sub>3</sub> pollution in the context of regional meteorology, transboundary transport, and anthropogenic emission changes.</p>

Chinese Regulations Are Working—Why Is Surface Ozone Over Industrialized Areas Still High? Applying Lessons From Northeast US Air Quality Evolution

“…However, over 2010, the observed NO 2 concentrations, which continued to decrease, are on the left side of the turning point (Figure 2b), thus emission controls in NO x led to effective reduction of O 3 concentrations. The remotely sensed measurements of OMI formaldehyde (HCHO) column data have been widely used to constrain anthropogenic and biogenic VOCs emissions (Cao et al, 2018;Stavrakou et al, 2018 (Sun et al, 2019). Furthermore, M. suggests limited change of anthropogenic VOCs emissions in China since 2013: VOCs emissions increased by about 3% in 2013-2017.…”

Rapid increase in summer surface ozone over the North China Plain during 2013–2019: a side effect of particulate matters reduction control?

“…380 Overall, the model results are comparable to those by using three-dimensional (3D) chemistry and transport models (e.g., Wang 2020a, 2020b). The MM model indicates that reduction of anthropogenic emissions of NOx was the greatest contributor (45 %) to the increase in surface O3 in the NCP region during 2013-2019, which was larger than Li et al, (2019a) in summertime from 2013 to 2017 (about 10 %) but less than that of Sun et al (2019) in July from 2003 to 2015 (63 %) over the 385 eastern China. Aerosol radiative effect was ranked as the 2 nd contributor to the change in surface O3 in this region.…”