The largest neighborhood air monitoring network in the U.S. allows residents to track Chicago air pollution in real time.
On light poles from Hegewisch to Humboldt Park, a new network of air quality monitors is quietly tracking the pollution Chicagoans breathe.
The project, known as Open Air Chicago, measures nitrogen dioxide (NO₂) and fine particulate matter (PM2.5) — pollution linked to a variety of lung and heart conditions.
The sensors are part of a city-wide effort to gather more detailed data on air quality after years of complaints from residents and environmental advocates in industrial corridors on the South and West sides. Many of those neighborhoods — largely Black and Latino — sit near warehouses, rail yards and manufacturing facilities that have been linked to health concerns like asthma, heart disease and premature death.
“You can’t manage what you don’t measure,” said former Chicago Department of Public Health official Raed Mansour, a longtime advocate for stronger community-based monitoring efforts. “For the longest time, those who had been most affected by air pollution bear the greatest burden to living a healthy life.”
The largest network in the nation
Over the summer, the city and researchers at the University of Illinois Chicago installed 277 solar-powered sensors across every community area — creating the largest citywide, hyperlocal air pollution monitoring network in the United States, and the second largest in the world.
Through the project’s online portal, residents can now view a live map of air quality and report excess pollution levels to city services.
Evidence of pollution disparities
Sensors are expected to clearly show pollution disparities throughout Chicago, supporting a 2025 finding that Latinos comprise 50% of the population in areas with the most particulate matter pollution but only make up 30% of the city’s population.
The health consequences of that pollution are already visible in Chicago’s public health data. Chicago consistently ranks among the worst U.S. metros for particle and ozone pollution, with the American Lung Association reporting failing grades for air quality.
Roughly 13% of Chicago residents have asthma, according to Rush University Medical Center, with some neighborhoods reporting rates above 17% — among the highest levels seen in major U.S. cities.
A Northwestern University study found that parts of Chicago’s West Side — including North and South Lawndale — experience nitrogen dioxide levels up to 32% higher than the city average.
Air-sensor studies have also identified pollution hotspots in Austin and Auburn Gresham, where residents are exposed to elevated levels of fine particulate matter.
Mapping pollution and inequity
The project uses environmental justice score indexing, which assigns higher scores to areas with higher rates of exposure to environmental hazards and social vulnerabilities, to map out placement of the sensors.
More sensors are clustered together in neighborhoods with higher cumulative environmental justice scores, including West and South Side communities Austin, West Garfield Park, North Lawndale, Englewood, and West Englewood.
Funded through a mix of city and research grants, and built in collaboration with community groups that have long demanded better data, the network is designed for transparency, planning, and public health.
How the sensors work
Communities can use data generated from the network to inform public health decisions, urban planning, and long-term exposure research, according to UIC Professor Serap Erdal, who led the network’s technical design. “One of the advantages of our network is that we designed it based on EPA ambient air monitoring criteria, but at a neighborhood scale,” Erdal said.
City officials say the near–real-time data can help residents — especially those with asthma and other respiratory illnesses — make informed decisions, while giving policymakers and researchers the granular information needed to track pollution trends, identify hotspots, and shape zoning, transportation, and industrial policy in communities that have historically borne the heaviest pollution burden.
Community-driven change
Mansour emphasized that residents’ input must take the helm of projects like this, comparing the collaboration of government, researchers and community to a “three-legged stool.”
“It doesn’t make for a good system unless all three are on board, and the community is the most important part,” he said. “It needs to be co-governed — equal voice from those that are most affected by pollution.” Mansour notes that residents used insider knowledge to plan where sensors were placed. “They know their communities best, and they know where things need to be,” he said.
Brian Urbaszewski, director of the Respiratory Health Association, emphasized how hyperlocal data can empower communities to combat industrial facilities that have long been the culprits for pollution in Chicago.
“It’ll be useful for environmental justice groups or community groups that are concerned about large polluters in their neighborhood — large factories, refineries, or chemical processing facilities,” he said.
Urbaszewski highlighted the importance of local monitoring to fill gaps left by distant federal sensors.
“When you have local polluters and the air monitor might be miles away from your community, those communities were eager and quick to adopt these affordable air quality monitors to get something in their hands that they could show — that what they were complaining about was real, and that they were tracking it,” Urbaszewski said.
Grassroots monitoring efforts
Many local environmental justice groups, including Little Village Environmental Justice Organization and the Southeast Environmental Task Force, had been using small-scale monitors for over a decade.
According to Urbaszewski, the effort to create a citywide monitoring system grew out of grassroots initiatives in communities that had already adopted sensors and wanted to scale them into a more stable and coordinated network.
Grace Adams, project administrator for the Chicago Department of Public Health, explained that the “snapshots” of air quality generated by the network sensors can be used to identify areas with consistently poor air quality and inform the deployment of federally regulated monitors for enforcement if violations are found.
Researchers and regulators can use records of spikes in PM2.5 and nitrogen dioxide levels to pinpoint likely sources of pollution, such as truck traffic or factory emissions.
Using data to hold polluters accountable
Mansour said the sensors, which are low-cost, can serve primarily as an educational tool for communities and a starting-point to demand greater regulation. What matters most now, he said, is turning the data into policies and programs that reduce pollution.
“Community has long sought this type of hyperlocal air quality data to understand the air pollution burden on them,” Mansour said.
Mansour framed the project as a matter of equity and public health: “Those most affected are the frontline communities. They are the least responsible for these issues, just like in climate change. This work should be done expeditiously to save lives, improve health and well-being, and prevent illness and death–that’s the basic tenet of public health.”