Influence of Cloud/Fog on Atmospheric VOCs in the Free Troposphere: A Case Study at Mount Tai in Eastern China

Cloudy and foggy conditions at Mount Tai in eastern China significantly increase the accumulation of atmospheric volatile organic compounds (VOCs), with oxy-VOCs (OVOCs) contributing 67% to total VOCs on cloudy/foggy days compared to 72% on non-cloudy days. Acetone emerged as the most abundant compound, reaching 18 ppb under cloudy conditions versus 15 ppb otherwise. Surprisingly, while overall VOC concentrations rose in cloudy/foggy weather, most OVOCs were more prevalent during non-cloudy periods, suggesting atmospheric photochemical reactions play a role in their depletion. Air mass trajectory analysis linked increased VOC levels to pollution from heavily industrialized regions. The study highlights that VOC dynamics at Mount Tai are influenced by a complex interplay of factors including cloud/fog presence, temperature, humidity, wind speed, and direction, with OVOCs and aromatics being key contributors to ozone formation potential.

Yang, F., Wang, Y., Li, H., Yang, M., Li, T., Cao, F., Chen, J., & Wang, Z. (2017). Influence of Cloud/Fog on Atmospheric VOCs in the Free Troposphere: A Case Study at Mount Tai in Eastern China. Aerosol and Air Quality Research, 17(10), 2401–2412. https://doi.org/10.4209/aaqr.2016.12.0536