Why The Air Gets Bad When the Sun Comes Out

May 7, 2018

This past week brought the first real taste of spring or maybe even summer weather. Along with the warmth came something less desirable -- air quality alerts. From Connecticut to southern Maine, ozone levels mid-week rose to what the EPA considers unhealthy for those with asthma or other lung problems.

“We had our first warm day, a lot of sunshine, and unfortunately, ground level ozone issues,” said EPA regional administrator Alex Dunn.

Ozone forms when strong sunlight hits exhaust from vehicles and power plants (in the form of volatile organic compounds and oxides of nitrogen).

Not surprisingly, the worst air quality tends to be where the most traffic and other engines are being used, Dunn said.

“We have a lot of people… using small, gasoline-powered engines, their lawn mowers, string trimmers, chainsaws, air compressors and leaf blowers.”

Despite the myriad pollution-creating machines in our neighborhoods, there’s good news, too. Ozone air pollution is actually better today than it was in the 1980s.

For example, in 1983, 120 days were bad days for ozone pollution in Massachusetts using today’s standards. In 2017, there were only 25 bad days for ozone pollution.

“Certainly the long-term trend shows that our work to improve air quality is working,” Dunn said. “But we do have to be ready for changes with the climate.”