The climate crisis brings more health risks due to air stagnation

Summer heat waves are becoming more frequent and with that, more air pollution.

Persistently hot weather patterns trap air pollutants in the lower elevations of the atmosphere, in a phenomenon known as stagnation. These nearly stationary domes of hot air may hold particulates and ground-level ozone, causing respiratory distress and eye irritation. Add to that, increasing wildfire frequency and we could have significant health problems.

The NOAA/NCEI Air Stagnation Index incorporates upper atmospheric winds, surface winds, and precipitation to calculate the daily level of stagnation.

Scientists at Climate Central analyzed that data and found that since 1973, 98% of cities analyzed show a positive correlation between summer heat and the number of stagnant days. Only 5 cities along the California coast lack the correlation; their local heat comes from downsloping, offshore winds which mix up the air and limit the stagnation. This may not mean they have more healthy air however.

As our climate crisis worsens, summer temperatures are expected to go up across most of the country, worsening health issues from the air pollutants that become trapped. Although the Clean Air Act of 1970 has significantly improved the air, some major cities have shown a recent uptick in the number of unhealthy days. As our climate warms, these unhealthy days are projected to increase with up to 40 more days by late-century.

If we cut our climate-warming emissions, it would really help the air we breathe.

-Meteorologist Eric Sorensen

Further reading:
The NOAA/NCEI Air Stagnation Index
The U.S. Clean Air Act
Why air quality is worsening in some U.S. cities

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