The installation of modern pollution controls on power plants and retirement of old plants, the increasing reliance on renewable energy sources and natural gas over coal, and the creation of more stringent fuel emission standards have all contributed to the pollution declines, he says.
Nolen says the Clean Air Act of 1970 accounts for the progress that's been made in cleaning up America's air.
The report covers data collected by states and local governments from 2013 through 2015. "Cleaner power plants, cleaner vehicles and cleaner diesel engines are all requirements of the Clean Air Act that are driving pollution reductions".
The six metropolitan areas on the complete most polluted cities list which also had at least some days where air pollution did not reach unhealthy levels includes, Elmira, New York, Wilmington, North Carolina, Burlington, Vermont, Melbourne, Florida, and the Fort Myers and Naples region of Florida.
Lehigh County averaged two high ozone days and earned a grade of "C", compared to more than four days and an "F" past year.
The 2017 report finds that Delaware's air quality has improved in parts of the state, but still needs work, particularly in New Castle County.
Sharks even series with 7-0 win over Oilers in Game 4
Zack Kassian has the early lead on the unexpected hero label in Edmonton's first trip to the Stanley Cup playoffs in 11 seasons. NFL Hall of Famer Jerry Rice opened the dressing room to lead the Sharks on the ice to start the game.
In Nebraska, Grand Island is ranked as one of the cleanest US cities with short term particle pollution.
While air quality has improved, there is a continued increase in unsafe spikes in particle pollution that is putting Americans' health at risk, according to the American Lung Association's 2017 State of the Air report. These three are the only eastern counties on the list for the top 40 most polluted.
The annual ranking of high particle pollution represents the concentration of particles in a cubic meter of air.
There was an average of 20 days per year between 2013 and 2015 when the air was considered unhealthy because of particle pollution, the recent data showed.
Houston has improved its ozone pollution levels since 1996, when records started to be kept. From 2013 to 2015, Luzerne County had 0.7 days per year with unhealthy, elevated levels of ozone.
He said the fine particulates can penetrate deep into the lungs and even the bloodstream, exacerbating asthma and increasing risk of heart attacks, lung cancer and premature death.
Number of asylum seekers illegally crossing border continues to rise
The arrests are part of an ongoing joint four-month investigation by Canada and U.S. authorities into organised human smuggling. The CBSA says nine foreign nationals were in her vehicle, who had failed to report to the CBSA upon entering Canada.
California has the dubious distinction of being home to the majority of the Top 10 cities with ozone and particle pollution in the United States.
"It causes increased risk in cancers and also irritation in lungs", Dr. Giri Hoskere, a Pulmonologist with Wellmont Health System says.
Ozone, meanwhile, forms when pollutants emitted by cars and other sources react with sunlight.
"The Central San Joaquin Valley is known to have some of worst air in the country", said Justina Felix, advocacy manager for the American Lung Association.
"I see the health effects of air pollution first-hand", Dr. David Hill, a Yale University medical professor who serves as a regional vice-chair for the lung association.
Improvements in ozone and average annual particle pollution were offset, however, by worsening short-term spikes in particle pollution.
Petrol Bunks in TN, Pondy to Close on Sundays from May 14
The decision will also be communicated to the oil supplying companies soon, he said almost 20,000 outlets will be closed on the holiday.