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Here’s what experts say about the hazy skies and air quality

The Boston area witnessed a fiery sunset on Tuesday. This view was captured at Duxbury Beach.David L. Ryan/Globe Staff

For Massachusetts residents who have taken note of the hazy skies and eerie red sunlight this week: You were not imagining things.

The state Department of Environmental Protection issued its latest statewide air quality alert this week due to smoke from hundreds of wildfires, burning across a number of Canada’s provinces, that affected much of the Northeast.

We’re tracking the latest air quality readings in New England in this interactive map.

But why is this happening, and how does it affect us? Here’s what experts say.

How do wildfires affect air quality levels?

In the case of wildfire events, experts said that the burning of trees, grass, and other material can release chemicals and particles that can affect air quality.


However, it’s small particulate matter that is of most concern, according to Dr. Jeremy Weinberger, a pulmonary and critical care physician at Tufts Medical Center. Weinberger said this particulate matter, 20 times smaller than the diameter of a human hair, can be particularly harmful to our lungs and is being carried down into the state along with the smoke from the Canadian wildfires.

Jonathan Levy, a professor of environmental health at Boston University, said this particulate matter can travel thousands of miles in the atmosphere, and so “even if the wildfires aren’t happening locally, it still affects us locally.”

Petros Koutrakis, a professor of environmental sciences at Harvard University, said wildfires also pollute the air by generating soot and organic particles, which can be toxic to respiratory and cardiovascular health.

He added that there has been a rise in air stagnation in the northeastern United States, which allows for a buildup of wildfire-related pollution over the region.

Smoke from wildfires in Canada shrouded Washington Street (Route 1) in Wrentham on Tuesday. John Tlumacki/Globe Staff

How harmful are current air quality levels?

Weinberger said the current air quality alert is specifically aimed at “sensitive populations,” which includes young children, older people, and those with underlying health conditions, including asthma and cardiovascular conditions. For example, those with asthma who have prolonged exposure to the small particulates in the air may see an increased amount of inflammation.


Weinberger added that there are also longer term health effects to this air pollution such as decreased lung function and increased risk of cardiovascular diseases.

However, Weinberger recommended everybody should be paying attention to their bodies and take precautions.

Smoke and clouds in the sky in Duxbury. David L. Ryan/Globe Staff

Should I be staying inside?

You might want to put off yard work and extensive outdoor exercise. If you do go out, consider wearing an N95 mask to reduce exposure to pollutants.

Indoors, set the air conditioner on recirculation mode.

Does this have anything do with climate change?

Although wildfire plumes entering the state are nothing new, Levy said there has been an increase in frequency and intensity of wildfires because of climate change.

“A lot of places, you’re getting longer drought conditions,” Levy said. “So that creates circumstances where wildfires can occur and can be larger at scale and scope.”

Koutrakis said that hotter temperatures from climate change result in increasing drought conditions, creating drier climates, dead biomass, less moisture for trees, and essentially turning large forest areas into firewood.

These extreme weather conditions create the right circumstances and more fuel for a wildfire to occur, Levy said.

Levy said while air quality in Massachusetts has been improving for some time, that trend has reversed in recent years with increasing harmful particulate matter polluting the air. He noted that the increasing number of wildfires is a component of that reversal.

“Climate change is not this abstract notion in the far-off future,” Levy said. “We’re being affected right now by climate change today, tomorrow, and the next day.”


Sabrina Shankman of the Globe staff contributed to this report. Material from the Associated Press was also included.

Ashley Soebroto can be reached at Follow her @ashsoebroto.