Last week, as smoke from Canadian wildfires blanketed the Northeast and turned skies across Massachusetts brown, many turned to air quality alerts to determine whether the outdoor conditions were unhealthy for children, older adults, people with heart or lung conditions, and people with asthma.

While the thick haze reminded many that climate change is accelerating, it reminded others that the state’s ability to track air quality is actually quite limited.

Low-income communities, including the state’s 26 Gateway Cities, are disproportionately impacted by air pollution and the detrimental health outcomes that accompany it. Yet 17 of these former industrial cities do not currently have state-operated air quality monitors.

At a time when environmental justice communities are even more at risk due to federal rollbacks to clean air protections, the lack of monitors has some advocates speaking out as climate change continues to lay the groundwork for the dangerously hot and dry conditions that fuel wildfires.

“Investing in the technologies that can provide quick, hyperlocal data is one of the first lines of defense, particularly for communities with high asthma rates,” said David Melly, senior policy director at the Environmental League of Massachusetts. “[The state] has made a lot of progress, but it is expensive, and there are real gaps.”

Air quality alerts last week warned of elevated levels of PM2.5 — a mixture of solid particles and liquid droplets so small that they can be inhaled deep into the lungs and may even enter the bloodstream. Chronic exposure to PM2.5, ozone, or other types of particle pollution contributes to high rates of asthma, heart disease, and other health problems, according to the American Lung Association. Poor air quality and high levels of PM2.5 can also trigger asthma attacks.

The Massachusetts Department of Environmental Protection (MassDEP) operates a network of 26 ambient air quality monitoring stations in 21 communities across the state, 10 of which are located in nine Gateway Cities: Brockton, Chelsea, Chicopee, Fall River, Haverhill, Lynn, Pittsfield, Springfield, and Worcester. A 27^th station operated by the Wampanoag Tribe is located on Martha’s Vineyard.

Additionally, MassDEP allocates grants to municipalities, nonprofits, and other local organizations for community-based PurpleAir sensors that measure PM2.5 pollution for at least one year. There are approximately 450 of these locally operated sensors across the state, and organizations in eight of the 26 Gateway Cities have received grants for one or more of these devices, including Attleboro, Brockton, Lawrence, Peabody, Quincy, Salem, Westfield, and Worcester.

But that still leaves 11 Gateway Cities without a PurpleAir sensor or a state-operated air quality monitor.

More Context

• The air they breathe (July 2026)
• A new project is helping Chelsea residents better understand their air quality (May 2025)