Global source apportionment of aerosols into major emission regions and sectors over 1850–2017

<p>Anthropogenic emissions of aerosols and precursor gases have changed significantly in the past few decades around the world. In this study, the Explicit Aerosol Source Tagging (EAST) system is merged into the Energy Exascale Earth System Model version 1 (E3SMv1) to quantify the variations in anthropogenic aerosol concentrations, source contributions, and their subsequent radiative impact in four major emission regions across the globe during 1850–1980, 1980–2010, and 2010–2017. In North America and Europe, changes in anthropogenic <span class="inline-formula">PM_2.5</span> were mainly caused by changes in emissions from local energy and industrial sectors. The local industrial sector caused the largest increase in <span class="inline-formula">PM_2.5</span> in East Asia during 1980–2010 and decrease during 2010–2017. In South Asia, the increase in energy-related emissions dominated the rise in <span class="inline-formula">PM_2.5</span> levels during 1980–2017. During 1850–1980, the increases in emissions from North America contributed to the increase in the European <span class="inline-formula">PM_2.5</span> burden by 1.7 <span class="inline-formula">mg m⁻²</span> and the sources from the Europe were also responsible for the <span class="inline-formula">PM_2.5</span> burden increase in East Asia and South Asia by about 1.0 <span class="inline-formula">mg m⁻²</span>. During 1980–2010, East Asia contributed to an increase of 0.4–0.6 <span class="inline-formula">mg m⁻²</span> in the <span class="inline-formula">PM_2.5</span> burden in North America and Europe, while South Asia contributed about 0.3 <span class="inline-formula">mg m⁻²</span>. During 2010–2017, the contributions from East Asia to the <span class="inline-formula">PM_2.5</span> burdens in the North America, Europe, and South Asia declined by 0.3–0.6 <span class="inline-formula">mg m⁻²</span> due to the clean air actions in China, while the contributions from South Asia still increased due to the continuous increase in emissions in South Asia. The historical changes in aerosols had an impact on effective radiative forcing through aerosol–radiation interactions (<span class="inline-formula">ERF_ari</span>). During 1980–2010, a decline in North American aerosols resulted in a positive <span class="inline-formula">ERF_ari</span> change (warming effect) in Europe and a decline in aerosols in Europe caused a warming effect in Russia and northern China. The changes in <span class="inline-formula">ERF_ari</span> from the increase and decrease in aerosols in China during 1980–2010 and 2010–2017, respectively, are comparable in magnitude. The continuous aerosol increases in South Asia from 1980 to 2017 resulted in negative <span class="inline-formula">ERF_ari</span> (cooling) changes in South Asia, Southeast Asia, and southern China.</p>