Local climate justice activists are using community-run air sensors to track pollution and push residents to connect air quality with health.
Yvette Piña began getting headaches after she moved to Pilsen in 2005. Piña, who works as a website developer, said it’s hard to do her work whenever one strikes.
“It’s just that heaviness when you have a headache. You don’t feel like doing anything. It can kind of ruin the day,” Piña said.
When she contacted her doctor’s office to ask what might be causing them, a nurse told her to stay inside because of the poor air quality that day.
“I was like, what are you talking about?” Piña said. “We’re in Chicago. We’re in the United States. How can there be bad air quality here?”
Chicago ranks 13th worst in the nation for year-round exposure to fine particulate matter pollution, according to a 2025 report by the American Lung Association. The EPA has linked fine particulate matter, or PM 2.5, to negative health outcomes like heart attacks and decreased lung function.
The city recently installed a network of Clarity air sensors to track air pollution in vulnerable neighborhoods. Local environmental advocacy groups like Pilsen Environmental Rights and Reform Organization (PERRO) are working with officials to refine placement of each sensor’s predetermined location.
Some of these groups are putting up their own sensors, too. A study coordinated by researchers at the University of Illinois Chicago is providing funding for six organizations to put up indoor and outdoor PurpleAir sensors in areas the city network might miss.
While both sets of sensors present an opportunity to gather information, environmental groups say they’re particularly interested in using the data as a means for public engagement. Zitlalli Paez, the vice president of PERRO’s board, said she doesn’t think most people in her community see the connection between air quality and their health.
“We understand the health effects. So we understand the headaches and the nausea and the allergies,” said Paez. “We know there’s something. But I don’t think folks necessarily know where it’s coming from.”
“To them it’s probably just something in the background,” said Citlalli Trujillo, the president of PERRO’s board. “‘Oh, you know, the air smells weird today and I know it’s because of industry, but what can I do, what can I do about that?’”
Sonia Monet Saxon is the air monitoring program lead at Neighbors for Environmental Justice, or N4EJ, which is involved in both projects. Saxon said they’ve seen the same reaction in “sacrifice zones,” a term environmental justice organizations use to describe areas where human health is sacrificed for the sake of industry.
“Especially in sacrifice zones, in EJ neighborhoods, where people are vulnerable for all of these structural reasons, it makes sense that air quality is not going to be one’s top priority,” they said. “If resources are scarce it’s a lot harder to worry about something that doesn’t present immediate threats.”
Saxon said both the city’s Clarity sensors and environmental groups’ PurpleAir sensors can measure PM 2.5, but they’re deployed differently.
“The Clarity network is guided by technical standards and an EPA quality assurance model of how to make a citywide network grid,” said Saxon. “PurpleAir monitors to us are being framed as a way to fill in whatever sort of gaps [in area coverage] exist at the end of the day after the Clarity network has been installed.”
N4EJ and the Little Village Environmental Justice Organization (LVEJO) have both put up small sets of PurpleAir sensors before. Jocelyn Vazquez, the community science organizer at LVEJO, said they put up sensors in 2023 when Canadian wildfire smoke degraded Chicago’s air quality.
“Many of the people that had applied were people with children or people who had elder adults living in their homes,” she said. So LVEJO gave out free air purifiers with the sensors as a thank-you so hosts could protect themselves during the event. Now they’re awarding hosts $250 for their participation.
Paez, who also works with LVEJO, said the supplies provided along with the sensors are key.
“I see more attitudes shift once people are given resources,” she said.
LVEJO already does regular outreach about air quality in their neighborhood. The group’s community garden flies a color-coded flag that indicates the air quality index, a tool used to identify which groups are most vulnerable to health effects from current air quality conditions. Vazquez also brings a handheld air sensor to some of LVEJO’s regular cleanups at Douglass Park.
Vazquez said she’s seen youth get really interested in air monitoring data after volunteering with LVEJO.
“They’ve been consistently showing up,” she said. “Those are students that have been trying to connect with their teachers, trying to grow that air monitoring into not just public spaces but the educational realm.”
According to Paez, a key benefit of installing the PurpleAir sensors is the opportunity to talk to the people
hosting the sensors. She said hearing participants’ lived experiences could allow PERRO to make connections between occurrences like bad smells and air quality events that show up on the sensors.
Trujillo said she met an older woman at El Paseo Community Market who told her home smells so bad she has to wear a mask indoors, but she doesn’t know who to tell. Trujillo told her about the upcoming PurpleAir system and encouraged her to report the smell to 311.
“That’s why we have groups like ours,” Trujillo said. “To step in and fill in those gaps. Be that bridge between our [government] agencies and our community members.”
Ultimately, groups like PERRO and LVEJO want to empower the people they serve to act based on what they learn.
“I think it’s really important for them to be able to advocate for themselves,” said Vazquez. “We’re there to support, but they’re the ones that have the answers to what best benefits a community for them, for their lived experiences.”