An Introduction to Monsoon Air Quality

What images come to mind when I say “monsoon”? Likely stunning visuals of towering cumulonimbus clouds erupting over the mountains with torrential rainfall, flash flooding, and thundering skies illuminated by streaks of lightning dominant such mental reflections. But wait, we can discuss even more weather implications to track and study during the monsoon that relate to our air quality!

First as a quick background, I am grateful to have had prior career exposure working nearly 8 years as an air quality meteorologist for the State of Arizona. Making my way through the graduate school curriculum at Arizona State University studying the meteorological sciences, I initially didn’t appreciate, or even consider to be honest, the possibility of forecasting the weather with an air quality perspective. Long story short, a job opportunity opened up in Downtown Phoenix while finishing my PhD dissertation and the rest is history!

Air quality forecasting is a great example of applied meteorology, meaning that to accurately anticipate air quality behavior it also becomes necessary to be skillful in understanding how local and upper level weather patterns evolve. The background weather influences surface pollutant concentrations, extent of vertical mixing, dilution potential, spatial long-range transport mechanisms, chemical reaction rates, favorability for adequate dispersion, and even local pollutant recirculation potential. Now add the variability of day-to-day activity that goes with society living in a sprawling major metropolitan area to the mix and you up the ante on forecasting complexity. In other words, it’s not just about the weather but additionally understanding how and when human behavior affects pollutant emissions in context to varying weather regimes.

Not done yet, though! Another layer of complication for air quality forecasts are the underlying physical geography and biome of the regional landscape. Specifically, the combination of complex terrain and the seasonal biologic clock of different plant life both have unique contributions to our observed air quality that need to be factored into forecasts and modeling efforts. Furthermore, other what might be considered exotic sources of pollutant emissions are derived from vertical transport mixing of distant wildfire smoke, lightning emissions, and stratospheric ozone intrusions.

Monsoon air quality forecasts can be quite challenging!

-JWM

Photo: Jonny William Malloy

Comments

Popular Topics