PORTLAND — Breathing may be easier, but it can still be a risky proposition.

That is the finding of a statewide report card issued Wednesday by the American Lung Association.

“The 2018 ‘State of the Air’ report finds that Maine has taken some big leaps this year, with significantly less ozone than in years past,” American Lung Association Chief Division Officer Jeff Seyler said in a news release.

The report card counted the number of days when ozone levels were high and days on which high particle pollution was measured for the years 2014-16.

The findings placed Maine cities and counties among the nation’s best. Both Bangor and the area extending from South Portland to Lewiston, with 2016 populations totaling 789,000, had some of the lowest measured particle pollution over 24-hour periods. Neither area was among the nation’s top 25 for year-round particle pollution.

Bangor was listed as one of the 56 cities nationwide with the safest ozone levels.

Among the nation’s most polluted areas were Fairbanks, Alaska, and Bakersfield, California, for particle pollution. Bakersfield also ranked high for ozone pollution, while the Los Angeles area topped the national list.

“More than four in 10 Americans — 133.9 million — live in counties that have unhealthful levels of either ozone or particle pollution, where their health is at risk,” Seyler said.

Cumberland County was given a B in ozone levels, with two days of high ozone. With no days of measured high particle levels, Cumberland County earned an A.

York County had the most days of elevated ozone levels, with seven, leading to a grade of D. Air particle levels were not monitored in York County.

The report card noted improvements in ozone levels in six of 10 counties measured, while three counties continued to get A’s. No failing grades were given, and Hancock County improved to a C while having five days of elevated ozone levels.

Particle pollution levels were completely measured in six of 12 counties, while measurements for ozone and particle pollution levels were incomplete or not compiled in Franklin and Sagadahoc counties.

Ozone pollution is also referred to as smog, while particle pollution is also referred to as soot, the Lung Association news release noted.

“Particle pollution is made of soot or tiny particles that come from coal-fired power plants, diesel emissions, wildfires and wood-burning devices,” said Lance Boucher, who directs public policy for the Lung Association in Maine.

Health complications from ozone and particle pollution include asthma, cardiovascular problems, lung cancer and developmental and reproductive harm, according to the news release.

Improved grades should not mean diminished vigilance, according to the Lung Association.

“While we are glad to see such improvements throughout the state, it’s important to remember that it only takes one bad air day to land a kid with asthma, or an elderly person, in the emergency room,” Boucher said. “We can and should do more to save lives.” 

Of the 292,000 Cumberland County residents, 107,000 were either age 65 or older or under the age of 18. Almost 125,000 people were considered to be in at-risk categories for health complications from pollution, although the study notes people can be in more than one category simultaneously.