Bottom Line: Understanding the sources that contribute to air pollution is essential for developing effective action to improve air quality and remove its associated health impacts. Adjoint modeling can be used to link sources of pollution to receptors to identify the most important drivers of local or regional air pollution.

Research: We perform adjoint sensitivity calculations to characterize the sensitivity of pollution in a predefined region of interest (e.g., a city or country) to emissions from different chemical species, locations, time periods, and sectors. We then combine these sensitivities with gridded emission inventories to estimate the contributions from different sources to pollution in the region of interest.

In the above figure, we identify the major sources of PM_2.5-related premature deaths for each of the G20 countries (a) and distinguish domestic (i.e., self-contribution) sources from those imported via emissions upwind of each country. We estimate the total sectoral contributions to PM_2.5-related premature deaths (b) and compare the fraction of health impacts from domestic sources to CO₂ intensity (c).

Nawaz, M.O., Henze, D.K., Harkins, C, Cao, H, Nault, B, Jo, D, Jimenez, J, Anenberg, SC, Goldberg, DL, Qu, Z. Impacts of sectoral, regional, species, and day-specific emissions on air pollution and public health in Washington, DC. Elementa: Science of the Anthropocene 2021. 10.1525/elementa.2021.00043

Nawaz, M.O., Henze, D.K., Anenberg, S.C., Braun, C., Miller, J., Pronk, E. A source apportionment and emission scenario assessment of PM2.5- and O3-related health impacts in G20 countries. GeoHealth 2022. 10.1029/2022GH000713

Nawaz, M.O., Henze, D.K., Anenberg, S.C., Ahn, D.Y., Goldberg, D.L., Tessum, C.W., Chafe, Z.A., An assessment of the sources of air pollution-related health impacts and benefits associated with improvements in travel efficiency as a function of distance of policy implementation in fourteen US cities. Frontiers in Sustainable Cities 2023. 10.3389/frsc.2023.1102493

Nawaz, M.O., Henze, D.K., Huneeus, N.J., Osses, M., Álamos, N., Opazo, M., Gallardo, L., Sources of air pollution health impacts and co-benefits of carbon neutrality in Santiago, Chile Journal of Geophysical Research: Atmospheres 2023. 10.1029/2023JD038808