This coverage is made possible through a partnership between WBEZ and Grist, a nonprofit environmental media organization.Serap Erdal stopped at a light pole in the middle of Grant Park and pulled out her phone. Behind her, the city’s towering skyscrapers cut into a sunny, blue sky as she zoomed i n on her palm-sized map of the city. The researcher barely noticed the hum of buses, cars and cyclists buzzing in front of her. She was working out what was in the air.Fixed to the pole above her was one of the city’s solar-powered air quality monitors. The tracker, about the size of a tissue box, is part of the nation's largest community air quality monitoring network. Today, there are 277 air monitors collecting air pollution data from every ward and community area, with special emphasis on communities already overburdened by pollution.A bright green dot flashed on Erdal’s phone. She smiled.“Currently, the air quality index at this location is 31,” said Erdal, a professor of environment and occupational health sciences at the University of Illinois Chicago. The reading puts the air quality in Grant Park in the U.S. Environmental Protection Agency’s safest category, meaning it poses little to no risk to public health. Serap Erdal checks an air monitor on her phone. Tyler Pasciak LaRiviere/Sun-Times On that clear and breezy day in June, almost all of the city’s monitors were green. But one on the far South Side flashed yellow. Even on good days, pollution has an uneven impact from neighborhood to neighborhood.The air monitors are part of a 5-year project that went live last fall. They’re designed to collect local air data that can show Chicagoans real-time pollution figures that can help officials develop guidance for permitting, urban planning, and air-quality control.The network is about to be put to the test as it faces its first Chicago summer — the season when air pollution tends to worsen, in part, due to climate change.The project, called Open Air Chicago, can trace its origins back to 2018. The city sought to relocate the massive scrap-metal shredding operation General Iron from the mostly white Lincoln Park neighborhood to the predominantly Latino and Black Southeast Side. In 2021, local environmental activists filed a civil rights complaint with the U.S. Department of Housing and Urban Development, arguing the move discriminated against low-income communities of color and harmed their health.The city and community groups reached a settlement in 2023. It included the city-wide air monitoring network, which Chicago officials partnered with the University of Illinois Chicago to launch last fall at cost of over $4 million. “This air monitoring system is creating an ongoing record of what the air quality is in Chicago,” said Oscar Sanchez, the director of the Southeast Environmental Task Force, one of the groups that successfully filed the civil rights complaint. That’s data, he said, that advocates can use to corroborate if new policies are improving air quality or if there’s parts of the city with worse air than residents knew.Each air monitor is less than one mile from the next. The low-cost equipment measures on-the-ground concentrations of two airborne pollutants: Nitrogen dioxide, typically formed by the combustion of fossil fuels; and PM2.5, small particles tiny enough to pass through a person’s respiratory system and enter the bloodstream, just one-twentieth the width of a single human hair. Exposure to both the gas and PM 2.5 are linked to childhood asthma and cardiovascular issues.Air pollution is relatively seasonal. Even as air quality has improved over recent decades, it can still get particularly bad during the summer, when sunlight and warm temperatures cook emissions already in the air and form ground-level ozone. That seasonal smog can worsen air further when coupled with increasingly common smoke from recent wildfires.Experts say climate change is exacerbating these conditions in the Midwest.“We also have to deal with the consequences of increased frequency and intensity of wildfires,” Daniel Horton, an assistant professor of earth and planetary sciences at Northwestern University said. “That's a problem that doesn't necessarily occur in our backyards, but when the wind blows in the right direction, we suffer the consequences in the Midwest.” Grace Adams, project administrator at the Chicago Department of Public Health looks at one of the individual air sensor readouts on her phone.Tyler Pasciak LaRiviere/Sun-Times Wildfires have already burned through 2.5 million acres nationwide in 2026. That’s nearly double the 10-year average for this time of year. The recent surge in wildfires, tied in part to climate change, is reversing the country’s steady progress toward improving air quality, according to a recent study published earlier this month in the journal Science.As air pollution in the Midwest and across the country continues to respond to warming temperatures, Horton said the Open Air Chicago network will be able to identify localized pollution hot spots. It can give an “unprecedented look at the air quality landscape across the city,” he added.That’s because the local network will be able to build on top of existing data collected by the EPA’s handful of regional air monitoring sensors and satellite data from NASA.Carl Malings, an assistant research scientist at Morgan State University and NASA’s Goddard Space Flight Center, said the local data is especially important because, in many cases, satellites are capturing the messy interplay of particles and gases throughout the atmosphere’s layers, making it difficult to know what’s actually in the air people breathe.For example, a satellite can pick up a smoke plume moving over the Midwest, but in the absence of more information, it's hard to say whether that smoke is reaching the ground level and impacting human health or if it’s passing overhead.But combining higher spatial resolution data from satellites with Chicago’s low-cost ground network could offer the best look at how air pollution concentration levels vary by neighborhood, Malings said.Erdal said the program is funded through the beginning of 2030. City officials hope to keep the network online even longer. Still, she hopes the data collected over the next five years can help build a road map for city officials and community leaders to cut down Chicagoans exposure to unsafe air. Related Chicago area air quality among worst in U.S., report finds Chicago aims to have the most air pollution sensors in the U.S. ...read more read less