Warning to millions as toxic air carrying lung-penetrating particles sweeps across 10 states TODAY

A dangerous haze is creeping across parts of the US, threatening to turn ordinary summer activities into a health risk.

Millions of Americans across ten states are under air quality alerts as a combination of ground-level ozone, wildfire smoke and harmful particle pollution degrades conditions from the Northeast to the Southwest. 

Officials in New York, New Jersey, Connecticut, Rhode Island, Pennsylvania, Maine, New Hampshire, Colorado, Arizona and California have issued advisories warning that the air could become unhealthy, particularly for sensitive groups. 

Many of the alerts remain in effect through Wednesday evening, though some wildfire smoke advisories in Colorado began Tuesday and continue into Wednesday morning. 

Health officials are urging people to limit strenuous outdoor activity, remain indoors if smoke becomes thick and reduce physical exertion if they experience breathing problems. 

Children, older adults and people with asthma, heart disease or other respiratory conditions are considered especially vulnerable. 

In several states, residents are also being encouraged to reduce driving and avoid using gasoline-powered equipment to help curb pollution levels. 

Authorities warn that the tiny particles and elevated ozone levels can penetrate deep into the lungs and trigger coughing, shortness of breath, chest discomfort and other health problems.

The most widespread alerts stretch across the Northeast, where millions of residents in major metropolitan areas are being advised to keep a close eye on air quality conditions.

In New York, an Air Quality Health Advisory is in effect from 11am to 11pm ET Wednesday for New York City and surrounding communities, including Manhattan, the Bronx, Brooklyn, Queens, Staten Island, Nassau County, Suffolk County, Westchester County and Rockland County. 

State officials warned that ozone levels could exceed an Air Quality Index value of 100, a threshold considered unhealthy for some people. 

Residents with asthma or heart disease are being urged to consider limiting strenuous outdoor activity and to consult a physician if symptoms develop.

Across the Hudson River, New Jersey has issued multiple Code Orange air quality alerts. The warnings cover Bergen, Passaic, Hudson, Essex and Union counties, as well as Morris, Hunterdon, Somerset, Middlesex, Mercer, Monmouth, Camden, Gloucester and parts of Burlington County. 

The Philadelphia metropolitan area, including Philadelphia, Delaware County, Chester County and Bucks County in Pennsylvania, is also under a Code Orange alert, meaning levels are unhealthy for sensitive groups.

Residents are being encouraged to avoid strenuous outdoor exercise during the height of the pollution event.

Connecticut and Rhode Island are facing similar concerns.

Connecticut’s air quality alerts cover Fairfield, New Haven, Middlesex, Hartford, Tolland and Windham counties through Wednesday evening, with officials warning that ground-level ozone concentrations may approach or exceed unhealthy standards. 

In Rhode Island, an Air Quality Alert Day has been issued for the entire state, including Providence, Warwick, Newport and Block Island.

An Air Quality Alert Day means the air outside has high levels of pollution. Local or federal agencies issue these alerts, so locals know when the air could be dangerous to breathe 

Further north, parts of Maine and New Hampshire are also under alerts.

Maine officials warned that ozone levels could rise into the ‘Unhealthy for Sensitive Groups’ range across coastal communities, including Portland, Brunswick, Rockland and Bar Harbor. 

The state is also expecting moderate particle pollution statewide. New Hampshire has issued an alert for Interior and Coastal Rockingham County, including Portsmouth, Hampton and Seabrook, with officials warning that even healthy individuals may experience mild effects from the poor air quality.

Colorado is contending with a more complex threat as wildfire smoke from large blazes in southwestern Colorado and southeastern Utah spreads across wide sections of the state.

The Colorado Department of Public Health and Environment has issued Air Quality Health Advisories for dozens of counties, including communities such as Grand Junction, Aspen, Vail, Breckenridge, Colorado Springs, Pueblo and Fort Morgan. 

Officials warned that moderate to heavy smoke could linger through at least Wednesday morning and advised residents to remain indoors if smoke becomes thick in their neighborhoods.

The state has also issued an Action Day for Multiple Pollutants across the Front Range Urban Corridor, including Denver, Boulder, Jefferson and Larimer counties. In addition to wildfire smoke, continued hot and sunny conditions could drive ozone concentrations into unhealthy ranges. 

An Action Day for Multiple Pollutants is an official alert declaring that outdoor air quality is unhealthy. It is issued when weather conditions and high pollution combine to create dangerous levels of ozone (smog) and fine particles (dust and soot). 

Colorado residents are being encouraged to limit driving until at least Wednesday afternoon to help reduce pollution levels.

In Arizona, air quality concerns are centered on ozone pollution.

The Phoenix metropolitan area and the Flagstaff region are under High Pollution Advisories through Wednesday due to elevated ozone levels and the influence of the Pocket Fire near Flagstaff. State officials are urging residents to carpool, telecommute, use public transportation and reduce the use of gasoline-powered equipment.

Meanwhile, California’s Coachella Valley is battling a different threat.

An air quality alert remains in effect because of harmful particle pollution generated by windblown dust. 

Communities including Palm Springs, Indio and La Quinta have been warned that the particles can penetrate deep into the lungs and worsen asthma, heart disease and other respiratory conditions. 

Officials are urging residents to keep windows and doors closed, run air conditioning or air purifiers if available and avoid additional sources of indoor pollution.

With millions preparing for holiday travel and outdoor activities ahead of the Fourth of July weekend, health officials across the country are urging Americans to pay close attention to local air quality forecasts and take precautions before spending extended periods outside.