Aerosol Atmospheric Rivers as Drivers of Extreme Poor Air Quality Events
and Record PM2.5 Levels
Abstract
This study investigates the impacts of aerosol atmospheric rivers (AARs)
on extreme Particulate Matter 2.5 (PM2.5) levels (PM2.5 >
15mgm-3, as per the WHO) and on aerosol optical depth (AOD) extremes
(AOD > 98th percentile) over the US and the globe,
respectively, between 1997-2020. Results show that over various regions
over the US, extreme PM2.5values are associated with AARs up to 70% of
the time. Dust (sulfate) AARs are responsible for extreme PM2.5 levels
over the southwestern (northeastern and the east coastal) US. Organic
and black carbon AARs are associated with extreme PM2.5 levels over the
Midwest region of the US. Globally, AARs are associated with 40-80% of
the extreme AOD levels over the US, Sahel, Europe, Middle East, US,
South America, East Asia, India, and South Africa. Such associations
often lead to the highest or the second highest PM2.5 and AOD levels
recorded over those stations between 1997-2020.