The projected future degradation in air quality is caused by more abundant natural aerosols in a warmer world

• Higher concentrations of dust and secondary organic aerosol in the atmosphere, resulting from an intensified West African monsoon and enhanced emissions of biogenic volatile organic compounds, respectively, are projected to contribute to degrading air quality in a warmer world, suggest analyses of Earth system model simulations. Previous studies suggest that greenhouse gas-induced warming can lead to increased fine particulate matter concentrations and degraded air quality. However, significant uncertainties remain regarding the sign and magnitude of the response to warming and the underlying mechanisms. Here, we show that thirteen models from the Coupled Model Intercomparison Project Phase 6 all project an increase in global average concentrations of fine particulate matter in response to rising carbon dioxide concentrations, but the range of increase across models is wide. The two main contributors to this increase are increased abundance of dust and secondary organic aerosols via intensified West African monsoon and enhanced emissions of biogenic volatile organic compounds, respectively. Much of the inter-model spread is related to different treatment of biogenic volatile organic compounds. Our results highlight the importance of natural aerosols in degrading air quality under current warming, while also emphasizing that improved understanding of biogenic volatile organic compounds emissions due to climate change is essential for numerically assessing future air quality.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

emission rate variability

isoprene emission

united-states

climate

dust

model

pollution

impact

mortality

removal

Environmental Sciences & Ecology

Geology

Meteorology & Atmospheric

Sciences

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