Washington, DC, experiences cleanest air on record

Washington, D.C., has seen its cleanest air on record this year, going back to before the coronavirus pandemic began.

The city and the surrounding region have not seen a day with unhealthful air quality throughout 2020, the furthest the city has made it into the year with no unhealthful air quality days since 1980, The Washington Post reports.

The Washington metropolitan area has recorded air quality in the “green,” or good, range every day this year except for seven days when it was in the yellow, or moderate, range. The city has yet to enter the orange or red range for air pollution this year.

NASA air pollution specialist Ryan Stauffer told the Post that weather was a major contributing factor to the year’s air quality, noting that wetness and wind disperse pollutants, while air pollution is exacerbated by dry heat. The breezy and wet conditions since March have contributed to this effect, he said.

We’re now two weeks past the latest Code Orange ozone day on record in DC. We likely won’t have any shot until this weekend so the streak will continue pic.twitter.com/crT5qziRmP

— Ryan Stauffer (@ryans_wx) June 15, 2020

“It seems like the biggest impact this year is definitely the weather,” Stauffer told the newspaper. “We had so many days with rain, the pollution never had a chance to build up.” Meanwhile, he noted, the region has only seen three days over 90 degrees, while on average it would have experienced five by this point.

“I would expect at some point this summer, we will get a code orange,” said Stauffer. “This is really rare territory at this point.” Steamier, warmer weather is projected for the period between late next weekend and next week, as well as several days of predicted highs in the late 80s.

Vehicle traffic and emissions in D.C., like other major metropolitan areas, have dropped amid the pandemic and related business closures.

Traffic in the city has fallen about 40 percent, and other sources of pollution such as construction and industrial activities are also down, according to a briefing from the Metropolitan Washington Council of Governments provided to the Post.

An international report released in late April said global carbon dioxide emissions are expected to drop by a record amount this year amid shutdowns due to the pandemic.

“I do think [lockdowns are] contributing in some way, but it’s very difficult to quantify,” Stauffer told the Post about the cleaner air in the D.C. area.