Air quality, as a phenomenon, refers to the physicochemical state of the atmosphere with respect to the presence, concentration, and reactivity of gaseous and particulate constituents, including criteria pollutants (e.g., ozone, nitrogen oxides, sulfur dioxide, carbon monoxide, particulate matter) and numerous hazardous air pollutants. It emerges from dynamic interactions among emission sources, atmospheric transport, dispersion, chemical transformation, and removal processes such as deposition and scavenging. Quantification of air quality relies on continuous or episodic monitoring, expressed through pollutant concentrations and composite indices, and is central to studying atmospheric chemistry, exposure assessment, and the impacts of atmospheric composition on biological, ecological, and material systems.
Heavy, acrid wildfire smoke blanketed much of the eastern United States on Saturday, marring preparations for the weekend's highly anticipated World Cup final to be held in an open stadium in New Jersey.
Environment
Jul 19, 2026
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18
European countries continue to lead the world in environmental performance, according to the 2026 Environmental Performance Index (EPI), a biennial assessment produced by researchers at the Yale Center for Environmental Law ...
Environment
Jul 18, 2026
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97
Millions of people in the Great Lakes, Northeast and Mid-Atlantic states muddled through another day of unhealthy air from uncontrolled wildfires on Friday.
Environment
Jul 18, 2026
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8
Dense wildfire smoke billowing down from Canada set off unhealthy air quality alerts across the United States again on Friday, stirring concern over the weekend's World Cup final outside New York.
Environment
Jul 17, 2026
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9
Despite burning hundreds of miles away, Canadian wildfires have become a familiar source of disruption in New York state.
Plants & Animals
Jul 17, 2026
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17
Smoke from wildfires—which are burning more of the Northern Hemisphere as Earth warms—attacks nearly every system in the human body, killing tens of thousands of people a year, numerous medical studies show.
Environment
Jul 17, 2026
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The Manhattan skyline was obscured by thick haze, and Chicago closed its beaches Thursday as out-of-control Canadian wildfires raged, sending smoke spewing into the United States and exposing millions of people to dangerously ...
Environment
Jul 17, 2026
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11
Heavy, pungent wildfire smoke darkened skies in the U.S. on Thursday from the Great Lakes to parts of the East Coast, reducing visibility and prompting warnings that breathing the air outside could be dangerous.
Environment
Jul 17, 2026
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9
Toronto had the worst air quality of any major city in the world Wednesday, the Swiss firm IQAir said, as Canadian authorities urged people to stay indoors.
Environment
Jul 16, 2026
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13
Thousands of visitors were told to evacuate a remote Minnesota wilderness area accessible only by boat as wildfires send dangerously heavy smoke over the U.S. Midwest and Northeast this week.
Environment
Jul 16, 2026
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9
