Impacts of terrestrial vegetation on surface ozone in China: from present to carbon neutrality

Abstract

Despite many efforts to control anthropogenic sources, high ambient ozone (O _3 ) concentrations remain a serious air pollution problem in China. Terrestrial vegetation can remove surface O _3 through dry deposition but also enhance surface O _3 through biogenic volatile organic compound (BVOC) emissions. However, the net impacts of terrestrial vegetation on surface O _3 remains unclear. Here, we perform simulations using a chemistry-vegetation coupled model to assess the impacts of terrestrial vegetation on surface daily maximum 8 h average (MDA8) O _3 in China through biogeochemical processes, including BVOC emissions and stomatal uptake. The results show that vegetation biogeochemical processes increase summer mean surface MDA8 O _3 by 1.3 ppb in the present day in China, with 3.7 ppb from BVOC emissions but −2.7 ppb from stomatal uptake. However, the enhanced summer mean surface MDA8 O _3 from vegetation biogeochemical processes decreases from 5.4 to 2.7 ppb in the North China Plain (NCP), from 7.2 to 0.8 ppb in the Yangtze River Delta (YRD), from 8.7 to 1.8 ppb in the Sichuan Basin (SCB) and from 4.2 to 0.4 ppb in the Pearl River Delta by the period of carbon neutrality. Our study highlights that carbon neutrality-driven emission reductions can greatly mitigate the enhanced surface O _3 related to terrestrial vegetation, though there is still a positive impact of terrestrial vegetation on surface O _3 in some hotspots, including the NCP and the SCB.

Keywords

• ozone
• vegetation
• carbon neutrality
• GC-YIBs