Volunteers monitored the air pollution in Beloit. A new worldwide report shows how bad it is.

Back in the fall of 2022, a group of Beloit residents concerned about climate change began monitoring air pollution in the southern Wisconsin industrial city. It was the first time that anyone had systematically surveyed the community’s atmosphere.

The early results were troubling, indicating notably high levels of air pollution. The monitoring efforts continued, with the data recorded and displayed in real time on a publicly accessible website.

Now a new report that compiles the results of 30,000 air monitoring stations around the world has thrown a new spotlight on the project — identifying the city’s air pollution in 2023 as worst among U.S. cities and 14th worst in North America.

That’s not surprising, says Pablo Toral, a Beloit College environmental studies professor and an organizer of the community volunteer air monitoring project.

But there’s also a catch: Beloit’s only on the list because of that project.

“There’s a huge vacuum there,” Toral says. “There are many communities in Wisconsin where I would hypothesize that the air pollution is much worse than Beloit — but they don’t have any sensors.”

The 2023 World Air Quality Report is produced by IQAir, a Swiss company that makes air filtration and monitoring technology. The firm maintains a global platform that collects air monitoring data from governmental agencies, nonprofit organizations and other sources around the world.

Producing the report, now in its sixth year, reflects IQAir’s niche as a comprehensive air quality company and its objective “to provide people all over the world with information and also solutions to protect their health from breathing poor quality air,” says Christi Chester Schroeder, air quality science manager for IQAir.

Particulate matter

The IQAir report focuses on measurements of particulate matter air pollution that is 2.5 microns or smaller — known as PM2.5 air quality data. (By comparison, a typical human hair is about 50 microns across.)

The term particulate matter might sound like fine dust, but it’s a broader, catch-all term. “While they are called particles, they’re actually aerosols … complex mixtures of gases and particles,” Shroeder says.

Pollutants detected at that size can include everything from fine metal dust from a metal-working factory to the substances produced when nitrogen oxides released from burning natural gas mix with other compounds in the atmosphere.

“In many regions, intense pollution events coincide with extreme heat, exacerbated by air stagnation events where weak winds hinder ground-level ventilation, allowing pollutants to accumulate,” the report observes. “As climate change progresses, the frequency of such events is anticipated to increase.”

IQ Air also seeks to document inequities in where the air is monitored as well as and where it’s not — but should be.

“If you look at places like Latin America and Africa, those areas are drastically underrepresented,” Schroeder says. There are fewer than 300 real-time air monitoring stations on the African continent, for example. “That’s woefully underrepresented in terms of being able to provide people with real-time information about what’s going on with their air — or information, period.”

The Beloit air monitoring project grew out of efforts by Toral and others in the community concerned about climate change to document what sources of emissions in the region might be contributing to the production of gases that can trap warmer air in the lower atmosphere — a key cause of global warming.

Sponsored by Thriving Earth Exchange and supported by the advocacy group Healthy Climate Wisconsin (then called Wisconsin Health Professionals for Climate Action),  the group arranged to borrow a group of air monitors from the U.S. Environmental Protection Agency for six months. The loan was extended for another six months, and those monitors were returned in the fall of 2023, Toral says.

The group held events presenting their findings to the community, and more people got interested in supporting the project. Through additional grants and donations, the group was able to replace all of the borrowed monitors, keeping the monitoring project going for the long term.

The monitors relay their readings to a platform maintained by PurpleAir, an air monitor and air quality mapping company. The Beloit group has encouraged local residents to visit the site to learn more about the emissions in the community.

The IQAir report came as a surprise when the company “reached out to us to inquire about the reason behind this project and compliment the community on the really good data,” Toral says. IQAir also has donated additional air monitors to the project. 

The report records the average levels of PM2.5 or larger pollution in micrograms per cubic meter. A 2021 World Health Organization standard calls for reducing PM2.5 levels in the air to 5 micrograms per cubic meter — a standard reached so far by 10 out of 134 regions and countries and by 9% of cities that have reported data.

Beloit’s average levels in 2023 were nearly three times the standard — 14.8 micrograms per cubic meter, according to the report. A half-dozen major U.S. cities listed showed lower levels ranging from 5.8 micrograms per cubic meter for San Francisco to 13 micrograms per cubic meter for Chicago.

Worst in the U.S.

Beloit ranked 14th on the report’s list of 15 most polluted cities in Canada and the U.S. — and was the only U.S. city on that list. The report says that the 2023 Canadian wildfires significantly influenced air quality in both countries.

The report also mentions Milwaukee, where average PM2.5 concentrations rose 51% from 2022 levels, averaging 11.8 micrograms per cubic meter in 2023.

The IQAir report shows that worldwide, pollution conditions range widely. One chart compares national capitals from New Delhi, India (92.7 micrograms per cubic meter) to San Juan, Puerto Rico (2.7 micrograms per cubic meter).

Some 70 countries and more than 3,000 cities reported PM2.5 concentrations in 2023 that were lower than in 2022, Schroeder says, including countries as varied as Germany, Peru and Algeria.

“In some places it’s getting worse,” she adds. After declining for five years,  PM2.5 levels in China rose in 2023. “It’s getting worse in South Asia — places like Pakistan, India, Bangladesh.”

There are three major contributors to air pollution, Toral says — automobile emissions, manufacturing emissions and fossil fuels from electric power generation. Beloit and Milwaukee both have all three.

Pollution contributes to poor health, and Toral says higher rates of respiratory and other illnesses in Rock County, where Beloit is located, likely reflect that connection. And cities like Beloit, or Milwaukee, have been vulnerable — accustomed to pollution and their populations less politically powerful, he adds.

Cleaning up the air can’t be left just to individual communities, but requires a comprehensive approach in his view. “It has to be a statewide effort to prevent the displacement to other communities,” he says.

For cities like Beloit, the first lesson from the report is “that it’s very important not to make assumptions in places where there is no data,” Schroeder says. “Before you can make any meaningful change or impact or even understand what’s happening with the quality of air in your area, you have to have measurements.”

And the Beloit data is significant, she adds. After speaking with the Beloit group about their findings, Schroeder came away impressed.

“The data that they have is robust,” she says. “And it is my sincere hope that people take this seriously, that they don’t discount the value of the work that they’ve done and the findings that they have.”