Millions of Americans have been urged to remain indoors on Friday as a dangerous combination of wildfire smoke, ground-level ozone and fine particle pollution spread across 16 states, with health authorities warning the contaminated air poses serious risks to breathing and could trigger asthma attacks.
The National Weather Service issued the alerts covering Arizona, California, Colorado, Connecticut, Indiana, Kentucky, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania and Rhode Island. Depending on location, warnings range from single-day advisories to alerts lasting through Sunday night.
Authorities across the affected states are advising residents to keep windows and doors shut, limit strenuous outdoor activity and monitor local conditions. Health officials say those most at risk include children, older adults, pregnant people and anyone with asthma, heart disease or chronic lung conditions. Ground-level ozone, commonly known as smog, is the dominant concern along much of the East Coast, while wildfire smoke and fine particulate matter are affecting parts of the West and northern New England.
In New York, the state Department of Environmental Conservation issued an Air Quality Health Advisory running from 11am to 11pm Friday for New York City, Long Island and parts of the Hudson Valley, including all five boroughs alongside Nassau, Suffolk, Westchester and Rockland counties. Elevated ozone levels are expected to push the Air Quality Index above 100 — double the healthy threshold of zero to 50 — as emissions from vehicles, power plants and industrial sources react in sunlight.
New Jersey faces the longest-lasting restrictions, with the state’s Department of Environmental Protection issuing an Air Quality Action Day running through 11pm Sunday for multiple counties including Bergen, Hudson, Essex and Union. Code Orange alerts — warning that pollution may reach levels unhealthy for sensitive groups — have been issued for much of the rest of the state. Similar Code Orange warnings cover Pennsylvania’s Delaware Valley and Susquehanna Valley, Maryland’s Baltimore metro area, suburban Washington DC and the Charlotte and Raleigh areas of North Carolina.
In the north, smoke drifting from Canadian wildfires continues to degrade air quality across Maine, with particle pollution expected to periodically reach unhealthy levels through Sunday night. Residents have been told to limit outdoor activity if they can smell smoke or if visibility deteriorates.
The situation in the West is being driven partly by domestic wildfires. Colorado’s Department of Public Health and Environment warned that smoke from the Aspen Acres Fire and other major fires in southwestern Colorado and southeastern Utah could produce periods of moderate to heavy smoke, advising anyone whose home fills with smoke to consider temporarily relocating. California’s southern counties face an additional wave of poor air quality from Fourth of July fireworks, expected to create harmful conditions from Saturday evening through Sunday afternoon, while Arizona’s Phoenix metro area and Flagstaff are under ozone high pollution advisories.
