$500k federal grant will help Pima County track air pollution closely in its most affected areas

Pima County will track air pollution in its most affected areas with the help of a $488,000, three-year federal grant, Department of Environmental Quality officials said. About 30 air pollution sensors will be set up at schools in the Tucson, Flowing Wells, Vail and Sahuarita Unified Districts, among others.

The sensors will help track concentrations of particulate matter — small bits of solids and liquids, and gas pollutants such as ground-level ozone or carbon monoxide — though the county has yet to choose which gases it will track.

The grant, announced Tuesday, will be used over three years, and will also support the development of educational programs through the University of Arizona.

The county already tracks air pollution at 14 locations with monitors that help the county issue warnings for harmful levels of contaminants, most often for ozone but also for particulate matter when fires send ash into the air from surrounding areas.

However, these monitors are “limited in characterizing localized air pollution patterns across space and time,” according to the PDEQ grant application. What the county “really needs,” said PDEQ Director Natalie Shepp, is “to collect information in much smaller areas.”

“We have the data we get from our air pollution monitors, but they’re spread out throughout the city (of Tucson),” Shepp said. “Without additional data like what we will hopefully be getting from this, we really don’t know what we’re dealing with.”

The county will be looking for air pollution “hotspots,” according to their grant application, while they collect data that will help “enact targeted policies aimed at reducing emissions.” Shepp said the sensors will collect data that “will inform decisions about policies and government work.”

“We really would not have the means to identify localized issues — it’s a guessing grant — until we can get these sensors out there,” she said. “We really want to be able to better identify areas that might be dealing with more localized air pollution that could be affecting their health and that wouldn’t be picked up on our monitors because they’re too far away.”

The 30 outdoor sensors that the county is buying with the grant will give more details than the air monitors, including about how concentrated pollution is at certain points in the day and when it’s at its worst in different areas, according to the application.

Data collected from the sensors will be used to make predictive models, Shepp said, so the PDEQ can forecast air pollution levels across the county.

The sensors will likely be placed on campuses at the seven school districts that wrote letters of support for the PDEQ during their application for the EPA grant, Shepp said. That includes schools in Flowing Wells, Marana, Sahuarita, Sunnyside, Tanque Verde, Tucson and Vail.

Schools are “a great place” to set up the sensors, Shepp said, because it offers the chance to teach students about the project and air pollution in general.

“We’ll be allowing kids to learn, not just about air pollution and monitoring, but about how we can use that data to make policy decisions,” Shepp said.

Environmental justice

The project will also try to “promote environmental justice,” according to the application. The EPA defines environmental justice as “the fair treatment and meaningful involvement of all people regardless of race, color, national origin, or income,” according to their website.

“The EPA puts so much money into modeling as it relates to environmental justice because they understand that it’s the data that will tell the story in addition to people,” Shepp said.

In their grant application, the county acknowledges “that minority and low-income populations are disproportionately exposed to higher air pollution levels.” Shepp said the same trend is true in Pima County and Tucson.

The county has yet to pick which schools will host their sensors. “Most of them would probably be on the South Side (Tucson),” Shepp said, but she also wants to put some in areas for comparison. Most of the schools will also be near Interstate 10, according to the application, "because of a lot of new expansion" near the highway.

“Environmental justice is of considerable importance to the residents of eastern Pima County, particularly on the South Side of Tucson,” according to the grant application, because of a history of groundwater contamination there along with “a disproportionately high number of air pollution sources” placed in areas with more minority and low-income populations.

“We do anticipate putting most of them in areas that we suspect would have higher chances of being exposed to air pollution,” Shepp said. “But it’s also important to consider putting them elsewhere, in other areas that might not be considered environmental justice communities so we can do comparisons.”

The sensors also have to be put in a safe location, where they can’t get vandalized, and in a spot where they have constant access to power and wifi as the sensors will be internet-connected to give real-time air pollution measurements.

The data and predictive models will be paired with datasets put together by the UA College of Public Health and its students to estimate how long people are exposed to air pollution in certain areas and to help find pollution “hotspots.”

The UA will also help put together and host educational sessions about air pollution and its health effects. Student interns will work with the county to set up the sensors, collect the data and create predictive models for the pollution, Shepp said.

Arizona Asthma and Airway Disease Research Center and the Southwest Environmental Health Sciences Center, both of which are at the university, will also be a part of the project and study what the new data from the sensors can tell them about the health effects of air pollution, Shepp said.

In the summer, Pima County usually issues health warnings to Tucson metro area residents because ground-level ozone, a harmful gas created by car emissions and chemicals, has reached dangerous levels that can cause lung damage.

These warnings are more common in the hotter, summer months, especially July. In 2021, Pima County issued their first warning of the year in mid-June, but this year, the first two warnings came a week apart in early May. This year, the last ozone warning came in mid-August, while in 2021, the last one came in mid-September.