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 27th 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.
The Department of Public Health’s most recent five-year plan to address asthma in Massachusetts highlights 11 communities that are inequitably burdened by asthma. Nine of those were Gateway Cities, yet three — Holyoke, New Bedford, and Lowell — do not have PurpleAir sensors or an air quality monitoring station.
Springfield, the third largest city in the state with one of the highest asthma rates in the country, has one state-run monitoring station in the entire city. Worcester, the second largest city in New England also with one of the worst asthma rates in the country, has two, although one, located near the Worcester Regional Airport, does not measure PM2.5.
“MassDEP is committed to ensuring that every community across Massachusetts, especially those that have been historically underserved, has clean, healthy air,” a spokesperson for MassDEP said in a statement. “We continue to work with our communities and other partners to improve air quality across the state.”
Over the years, MassDEP has expanded the number of air quality monitoring stations it operates throughout the state. In 2025, two new stations were launched in Framingham and Saugus, bringing the total to 26. The department says that the stations have been strategically located in areas with higher pollution levels, asthma rates, and other risk factors. A spokesperson pointed to monitoring stations in communities like Weymouth and Fairhaven, which are adjacent to Gateway Cities.
Several of Massachusetts’s most vulnerable communities have abruptly lost millions in federal grants to address air pollution, asthma, and extreme heat. The cuts have largely targeted environmental justice programs. In April 2025 for instance, the Department of Public Health lost a $1 million grant from the Environmental Protection Agency that would have been used to address high rates of asthma in Western Massachusetts.
Meanwhile, some communities — including Chelsea, which has one of the highest rates of asthma in Massachusetts — have taken matters into their own hands with private air monitoring that does not rely on state or federal funding.
From 2023 to 2025, scientists and engineers at Northeastern University, in collaboration with the city of Chelsea and the local non-profit GreenRoots, installed and monitored more than 80 air quality sensors across the city to better understand neighborhood-level air pollution. The city has long had to contend with a litany of environmental hazards, including an endless stream of truck traffic and vehicle emissions as well as toxic lead paint and thick dust from the Tobin Bridge.
But Melly argued there are benefits to having air quality sensors and monitors that are run by the state.
“The data is only as good as what you do with it,” Melly said. “The state has such a broader ability to make informed policy decisions based on data it directly has access to.”
When it comes to air quality in underserved communities, “we don’t know what we don’t know,” Melly said, underscoring the need to first identify where the gaps are.
State Rep. Christine Barber, a Somerville Democrat who chairs the Joint Committee on Environment and Natural Resources, included a proposal in the House environmental bond bill to convene a committee of local experts to identify pollution “hot spots” across the Commonwealth and draft a plan to improve air quality in those areas. The bill, which passed in June, now goes back to the Senate for further consideration.
“For far too long, communities most burdened by air pollution have been overlooked. Harmful pollutants continue to pose significant health risks, especially for residents living near highways, ports, and airports,” Barber said. “Centering these perspectives in the identification process for air pollution hotspots is essential to addressing the needs of the disproportionately impacted communities.”
