Abstract
Abstract. Anthropogenic secondary organic aerosol (ASOA), formed from anthropogenic emissions of organic compounds, constitutes a substantial fraction of the mass of submicron aerosol in populated areas around the world and contributes to poor air quality and premature mortality. However, the precursor sources of ASOA are poorly understood, and there are large uncertainties in the health benefits that might accrue from reducing anthropogenic organic emissions. We show that the production of ASOA in 11 urban areas on three continents is strongly correlated with the reactivity of specific anthropogenic volatile organic compounds. The differences in ASOA production across different cities can be explained by differences in the emissions of aromatics and intermediate- and semi-volatile organic compounds, indicating the importance of controlling these ASOA precursors. With an improved model representation of ASOA driven by the observations, we attribute 340 000 PM2.5-related premature deaths per year to ASOA, which is over an order of magnitude higher than prior studies. A sensitivity case with a more recently proposed model for attributing mortality to PM2.5 (the Global Exposure Mortality Model) results in up to 900 000 deaths. A limitation of this study is the extrapolation from cities with detailed studies and regions where detailed emission inventories are available to other regions where uncertainties in emissions are larger. In addition to further development of institutional air quality management infrastructure, comprehensive air quality campaigns in the countries in South and Central America, Africa, South Asia, and the Middle East are needed for further progress in this area.
Highlights
Poor air quality is one of the leading causes of premature mortality worldwide (Cohen et al, 2017; Landrigan et al., 2018)
We introduce the ambient observations from various campaigns used to constrain Anthropogenic secondary organic aerosol (ASOA) production (Sect. 2.1), a description of the simplified model used in chemical transport models (CTMs) to better predict ASOA (Sect. 2.2), and a description of how premature mortality was estimated for this study (Sect. 2.3)
ASOA is an important – inadequately constrained – component of air pollution in megacities and urban areas around the world. This stems from the complexity associated with the numerous precursor emission sources, chemical reactions, and oxidation products that lead to observed ASOA concentrations
Summary
Poor air quality is one of the leading causes of premature mortality worldwide (Cohen et al, 2017; Landrigan et al., 2018). The models are estimating total OA correctly (Ridley et al, 2018; Hodzic et al, 2020; Pai et al, 2020), the attribution of premature deaths to POA instead of SOA formed from traditional and nontraditional sources, including IVOCs from both sources, could lead to regulations that may not target the emissions that would reduce OA in urban areas. As PM1 and SOA mass are highest in urban areas (Fig. 1), shown in Jimenez et al (2009), it is necessary to quantify the amount and identify the sources of ASOA to target future emission standards that will optimally improve air quality and the associated health impacts. The results provide insight into the importance of ASOA to global premature mortality due to PM2.5 and further understanding of the precursors and sources of ASOA in urban regions
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
