With more people working from home and fewer cars on the road during the pandemic, air quality in Hampton Roads and throughout Virginia has been notably boosted, according to the state’s Department of Environmental Quality.
On the average afternoon between 2016 and 2019, levels of ozone reached about 45 parts per billion in the region, according to state data, still plenty shy of what’s considered unhealthy. Between mid-March and late July of this year, the levels peaked at 40 parts per billion.
“I can’t recall seeing that before,” said Dan Salkovitz, a meteorologist with the department. “This is pretty clear there’s been improvement.”
Virginia monitors air quality 24/7 — at five sites in Hampton Roads, including NASA Langley Research Center, NOAA in Norfolk and the department’s regional office in Virginia Beach. Officials use the data in a daily air quality index, ranking days from good, or green, at best, and hazardous at worst.
Over the past five years, almost all days in Hampton Roads through early August have been considered green, according to state data, but an average of 23 days have been rated as moderate, or yellow. That’s not all the way to unhealthy, but could cause issues for people who are hypersensitive to some form of pollutant, Salkovitz said.
But this year, there have only been two yellow days.
For the most part, officials link all this to the precipitating drop in traffic volume over that time frame. During the early months of the crisis, traffic was down by almost half of its usual amount, though truck traffic didn’t drop much.
By this point, with some people heading back to work or venturing out, traffic is still only about 10% to 15% of its usual amount, Salkovitz said.
Ozone is not emitted by vehicles themselves, or out of smoke stacks for that matter. It’s formed from other pollutants, such as nitrogen oxides and hydrocarbons, through chemical reactions under sunlight. Warmer weather thus produces more of it, and extended rainy periods can bring levels down.
Nitrogen dioxide, another measure DEQ tracks, has been down recently too, but it was already so low that the change is hard to see.
None of this is contrary to long term trends in the state — air quality has been steadily improving, with some ups and downs, over the past few decades, Salkovitz said.
The worst year for pollution in Hampton Roads in that time frame was 1993, which saw 64 days with air considered unhealthy. Since then ozone levels have gone steadily down. The last year with any such days at all was 2016, at two.
“In a nutshell, air quality was good to start with. It’s just getting better,” Salkovitz said.
It’s a good short-term example, he added, of the direct impact reducing traffic can have on the air.
