The Washington, D.C. metropolitan area has seen an improvement in its air quality since early March, when the coronavirus pandemic started to hit the nation’s capital, prompting businesses to close and many residents to stay at home, according to the findings of the Metropolitan Washington Council of Governments (COG).
The D.C. region recorded only one day with “moderate” air quality, which was on March 19, from the beginning of March through April 20, the COG documented, while all the remaining days showed “good” air quality.
When it’s compared to 2019 data, a total of 17 days were reported to have moderate air quality between March 1 and April 20. Those days were March 2, 3, 8, 9, 12, 13, 25, 28, 29, 30 and April 3, 4, 6, 7, 9, 10, 18.
The drop in the number of bad air quality in the D.C. area during the same period this year is considered to be linked to shelter-at-home orders aiming to slow the spread of the coronavirus outbreak.
On average, the metropolitan area saw about 10 moderate air quality days in March and 14 in April up until 2020, which marks the cleanest air quality day in March since 2010.
Moderate air quality level “may pose a moderate health risk, especially for those who are unusually sensitive to air pollution,” while good air quality means that air pollution poses little or no risk, according to COG.
COG provides daily air quality forecasts for the D.C. area, cooperating with the District Department of Energy & Environment, Maryland Department of the Environment, and Virginia Department of Environmental Quality. Their forecasts are based on the national Air Quality Index, which focuses on health issues that result from breathing polluted air.