Enhanced O₃ concentration due to biogenic emissions during a hot summer in 2018 over the Tokyo metropolitan area, Japan

Abstract Photochemical ozone (O 3 ) is an important chemical component in the atmosphere as an indicator of air pollution. Anthropogenic sources, such as domestic automobiles and industries, have been considered a main source of O 3 especially in urban areas; however, recent emission regulations have led to declining trends in anthropogenic sources. Therefore, other sources, such as biogenic emissions, could be important in the near future. In addition, increasing temperatures caused by global warming will relate to increasing biogenic emissions. In this study, the role of biogenic volatile organic compounds (BVOC) on O 3 concentration was focused. The target period was a hot summer in 2018 in Japan, and O 3 concentration by simulating with and without biogenic emissions over the Tokyo metropolitan area was analyzed. The result clarified that around 20% (up to 63%) of O 3 was produced from biogenic sources at high temperatures, even in the Tokyo metropolitan area. This study suggested that the biogenic sources should be paid attention to and taken into account in the regulation of anthropogenic emissions.