Transport of volatile organic compounds found to cause worsening of regional ozone pollution

The increasing concentration of ozone (O₃) is a key factor contributing to the deterioration of air quality in China. O₃ and its precursors, especially volatile organic compounds (VOCs), could be transported by air masses, leading to interactions of O₃ precursors from biogenic and anthropogenic sources.

Consequently, O₃ pollution mainly shows regional uniformity. Qinling Mountain, with a high altitude, affects the climate and air quality in China, but its influence on VOC transport and regional O₃ pollution remains poorly understood.

Researchers from the Institute of Earth Environment of the Chinese Academy of Sciences conducted comprehensive observations on O₃ and its precursors to investigate the driving mechanism of the regional transport of O₃ and VOCs in the Qinling Mountain region and their impact on regional O₃ pollution.

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

The researchers found that the composition of VOCs at the foot of Qinling Mountain was significantly influenced by local sources, while the ambient VOCs near the top were influenced by the regional air mass, resulting in extremely high loading of O₃ and VOC loads at the top of Qinling Mountain during nighttime.

Furthermore, it was found that the East Asian summer monsoon and the local valley wind together drove the accumulation of O₃ (up to 152 ppbv) and VOCs (formaldehyde up to 5 ppbv) at the summit, exacerbating the O₃ pollution in the surrounding areas of Qinling Mountain.

This study improves the understanding of the transport of VOCs and its impact on the regional O₃ pollution, and the potential source distribution as well as transport pathways, which would be helpful in further regional O₃ quality control.