An unlikely gift of the coronavirus: Cleaner air in Charlotte as traffic dwindled

Charlotte’s air grew cleaner as traffic plummeted in the early stages of the coronavirus pandemic, Mecklenburg County air quality analysts say, confirming a suspected link between the two.

Traffic on Interstates 77 and 277 dropped more than 40% from March 26 to April 29, when the county was under a stay-at-home order, Mecklenburg’s air quality staff reported this week. Concentrations of pollutants linked to motor vehicle emissions also fell.

Concentrations of fine particles, carbon monoxide, nitrogen dioxide and ozone were all lower than average during the shut-down period, analysts found. Air monitoring stations that were close to roads showed greater decreases than stations that weren’t.

Ozone concentrations were also lower than would be expected due to weather conditions during the shutdown. Ozone forms most readily on hot, sunny summer days and less so on cloudy or rainy days.

“Local emission inventory data has long shown that, in Mecklenburg County, most ozone-forming air pollution comes from on-road vehicles like cars, vans and trucks,” the county said in a statement. “The results of the analysis reinforce that reducing pollution from vehicles is especially important to improve local air quality.”

Mecklenburg County updates its Air Quality Index daily. The county struggled for years to meet the federal health standard for ground-level ozone but is now in compliance with it.

Air pollution such as ozone irritates the lungs and respiratory system and can trigger asthma attacks, the N.C. Division of Air Quality says. Even healthy people can have trouble taking deep breaths on “bad air” days and can experience damage to lung tissues. Repeated damage, especially during childhood, can reduce lung function permanently.

Particle air pollution has been linked to serious cardiac problems, including arrhythmias and heart attacks.

This story was originally published August 26, 2020 at 4:55 PM.