Increasing concentration of ozone (O₃) is a key factor contributing to the deterioration of air quality in China. O₃ and its precursors, in particular volatile organic compounds (VOCs), could transport by air mass, leading to interactions of O₃ precursors from biogenic and anthropogenic sources. Consequently, O₃ pollution predominantly exhibits regional oneness. Qinling Mountain, with high altitude, affects the climate and air quality in China, but its influence on VOCs transport and regional O₃ pollution remains poorly understood. 

Researchers from the Institute of Earth Environment of the Chinese Academy of Sciences (CAS) conducted comprehensive observations on O₃ and its precursors to investigate the driving mechanism of the regional transport of O₃ and VOCs in Qinling Mountain as well as their impacts on regional O₃ pollution.

They found that VOCs composition at the foot of Qinling Mountain was significantly impacts on local sources, while ambient VOCs on the top was impacted by regional air mass, resulting in extremely high loading of O₃ and VOCs during nighttime at the top of Qinling Mountain. Furthermore, it was found that summer East Asian monsoon and local valley wind together drove the accumulation of O₃ (up to 152 ppbv) and VOCs (formaldehyde up to 5 ppbv) on the mountain top, exacerbating the O₃ pollution in the surrounding areas Qinling Mountain. 

This study enhances the understanding of the transport of VOCs and its impacts on the regional O₃ pollution, and the potential sources distribution as well as transport pathways, which would helpful in further regional O₃ quality control. 

This work was published in Journal of Geophysical Research- Atmospheres on Dec. 26. 2023.