Projected increases in wildfires may challenge regulatory curtailment of PM 2.5 over the eastern US by 2050

[摘要] Anthropogenic contribution to the overall fine particulate matter(PM 2.5 ) concentrations has been declining sharply in North America. Incontrast, a steep rise in wildfire-induced air pollution events with recentwarming is evident in the region. Here, based on coupledfire–climate–ecosystem model simulations, summertime wildfire-inducedPM 2.5 concentrations are projected to nearly double in North America bythe mid-21st century compared to the present. More strikingly, the projectedenhancement in fire-induced PM 2.5 ( ∼  1–2  µ g m −3 ) and its contribution ( ∼  15 %–20 %) to the totalPM 2.5 are distinctively significant in the eastern US. This can beattributed to downwind transport of smoke from future enhancement ofwildfires in North America to the eastern US and associated positiveclimatic feedback on PM 2.5 , i.e., perturbations in circulation,atmospheric stability, and precipitation. Therefore, the anticipatedreductions in PM 2.5 from regulatory controls on anthropogenic emissionscould be significantly compromised in the future in the densely populatedeastern US.

[学科分类] 医学（综合）