After two days of unusually colored skies and smoky air, experts expect air quality in New Hampshire to be unsafe for sensitive groups Thursday, while the situation in Vermont is less certain.
As wildfires continue in Canada, the New Hampshire Department of Environmental Services declared air quality unhealthy for sensitive groups Wednesday afternoon, issuing a “Code Orange” alert that will be effective across New Hampshire Thursday.
The notice replaces a smoke advisory issued by the department Tuesday afternoon.
Sensitive individuals include children and older adults, people with lung diseases and people who are active outdoors, according to a news release from the Department. People in these groups should avoid “prolonged outdoor exertion.”
“Even healthy individuals may experience mild health effects and should consider limiting strenuous or prolonged outdoor activities,” states the New Hampshire Department of Environmental Services in a press statement.
The haze is the result of small particles — less than 2.5 micrometers in diameter — which, when inhaled, can make their way deep into the lungs. The problem is made worse by relatively high humidity.
The smoke, which visibly changed the look of the sky starting Tuesday, is mostly the result of hundreds of wildfires burning throughout eastern and central Canada, as well as some wildfires in the northern plains region of the U.S.
In Vermont, the Department of Environmental Conservation opted not to issue an air quality alert for Wednesday, but was keeping an eye on the air quality and smoke forecasts as of Wednesday morning, Bennet Leon, section chief for the department’s air quality division, said Wednesday.
As of about 3:45 Wednesday, the agency had not issued an air quality alert for Thursday.
Smoke patterns have been “less obvious” in Vermont than in other areas further south and west making it more difficult to determine when to issue alerts, Leon said.
The agency bases the warnings on average air quality predictions across an entire day and takes a “conservative” approach, issuing alerts even if the air quality has a chance of being better than expected to be “more protective of public health.”
Air quality was considered moderate across the Upper Valley Wednesday morning, with a Lebanon station recording an 83 out of 100 air quality rating, according to AirNow, a monitor produced by the U.S. Environmental Protection Agency and other federal and state agencies.
At moderate air quality levels, people who are “unusually sensitive” to particle pollution should reduce time spent outside, according to the EPA.
As wildfires continue to burn in Canada, Leon said scientists expect that there will be more smoke in the region in the coming days, but cannot yet predict how bad the situation will be or when it will hit.
In general, it is difficult to forecast how wildfire smoke will impact air quality because of how smoke is influenced by changing weather patterns, Leon said.
“It’s really a day-by-day situation,” Leon said. “(…) With the wildfire smoke, as the weather changes it can kind of swirl around.”
The agency expected to make a decision about Thursday’s forecast by Wednesday afternoon.
New Hampshire has been fortunate so far. Well-timed rains have kept wildfire risk low or moderate for the entire summer with few outdoor blazes reported.
Fire danger was high across Vermont Wednesday and the state has seen 64 wildfires so far in 2026, according to data from the Agency of Natural Resources.
In Canada as of Wednesday morning, the National Wildland Fire Summary said 112 fires were burning “out of control” while 76 more are in various levels of control. So far this year, almost 3,500 wildfires have burned 4.7 million acres.
As alarming as that sounds, it is actually pretty good by recent standards: The average over the past five years is for twice as many acres to have burned in Canada by mid-July. That doesn’t make our skies any less smoky, however.
It also doesn’t hide the fact that things have been getting worse for a past quarter century as climate change has increased average temperatures, drying out forests and increasing storms that can produce lightning. The Canadian government says average acreage burned in that country each summer has roughly doubled over the past 25 years.
In other words, smoky skies that are hazardous to our health is now part of summertime in New Hampshire.
This story was updated at 3:50 p.m. Wednesday.
