Secondary Organic Aerosols in Polluted Atmospheres

Secondary organic aerosols (SOAs) are ubiquitous and complex components of atmospheric particulate matter, with far-reaching impacts on air quality, climate, and public health. However, substantial knowledge gaps persist in comprehending the intricate mechanisms governing SOAs formation, transformation, and removal processes across the diverse range of environmental conditions. Addressing these critical research needs is essential for developing accurate predictive capabilities and devising effective mitigation strategies for SOAs.

In urban and industrialized regions, SOAs are often dominated by anthropogenic precursors and complex photochemical processing, leading to changes in particle composition and air quality. For instance, the oxidation of volatile organic compounds (VOCs) emitted from vehicle exhaust, industrial activities, and consumer products can lead to the formation of complex organic aerosols that contribute to poor visibility and adverse health effects. In contrast, pristine environments are influenced more by natural emissions, where SOAs formation and aging can be driven by different mechanisms, such as the oxidation of biogenic VOCs from vegetation. Understanding these regional differences in SOAs characteristics is key to accurately assessing their impacts and developing effective mitigation strategies.

This Collection aims to advance our understanding of SOAs, from highly polluted urban areas to remote pristine regions. It will involve field observations, laboratory studies, and modeling approaches to not only develop more accurate climate and air quality projections, but also inform effective mitigation strategies.

We welcome Original Research articles as well as Reviews and Perspectives that contribute to this purpose, which includes the following topics, but not limited to:

1. Field observations of SOAs characteristics and formation mechanisms in diverse atmospheric environments, e.g., urban, rural, remote, and marine settings.
2. Laboratory studies of SOAs formation, aging, and transformation processes, including the role of anthropogenic and biogenic precursors, oxidation pathways, and multiphase chemistry.
3. Development and evaluation of SOAs module/models, from one-dimension box model to parameterization for large-scale climate and air quality models.
4. Satellite and ground-based remote sensing techniques for unveiling the spatial and temporal distribution of SOAs and their precursors.
5. Interdisciplinary studies linking SOAs properties and processes to their impacts on air quality, climate, and human health.
6. Innovative measurement techniques and analytical methods for the comprehensive characterization of SOAs composition, structure, and physical properties.
7. Strategies for mitigating SOAs formation and burden, e.g., targeted emissions controls, alternative product formulations, and land use plan.