Furthermore, 15 of the top 25 cities most polluted by year-long particle pollution saw reduced levels.
For short-term particle pollution, however, 15 of the 25 most-polluted cities tallied more days with spiked levels, a finding Nolen called concerning.
Bakersfield, California, was named the most polluted city for both short-term and year-round particle pollution, while Los Angeles-Long Beach was the worst for ozone pollution.
Once again, western Europe was enveloped in particle pollution.
Previous progress on short-term particle pollution, however, was undone.
Slowly the particle pollution in the chamber increased, in some cases by up to three times.
Easterly winds bought particle pollution across the eastern half of England in mid-February.
Wood-burning stoves and inserts put out vast amounts of fine particle pollution.
The instrument broadcasts a Twitter bulletin each hour providing a record of the airborne particle pollution.
Particle pollution control focuses on industry and traffic; less attention is paid to agriculture.
But CASAC members remained divided on the link between fine particle pollution and premature death.
