Adopting zero-emission trucks and buses can save lives and prevent asthma in Illinois

Guided by the living experiences of community partners, Northwestern University scientists simulated the impact of Zero Emission Vehicles (ZEVs) adoption on future air quality in Chicago’s Greater Area.

The results are published today in the Geoscience Frontier Journal.

Motivated by California’s Advanced Clean Truck (ACT) policy, neighbors for a fair transition to Zero Emissions (NET-Z) Illinois have partnered with Northwestern researchers to explore how similar strategies will unfold in Cook County and surrounding areas.

To develop a model that would more realistically simulate current pollution levels in the larger Chicago area, researchers have enhanced the Environmental Protection Act (EPA) air quality model to better reflect the satellite observations and the living experiences of local community groups. The researchers then compared the current model of air quality with a simulated future conditions under ACT policies.

By implementing an ACT policy in Illinois, researchers have found that the Chicago area reduces nitrogen dioxide (NO2) contamination sufficient to avoid 500 premature births and 600 childhood asthma a year. The biggest health improvements from this policy occur in neighborhoods that are currently experiencing the highest levels of contamination. Therefore, reducing air pollution not only reduces health problems, it also helps address existing racial disparities in pollution exposure.

“As a mom with personal asthma, I was impressed with these results,” said Victoria Lang of Northwestern, who led the study. “While avoiding 600 new pediatric cases of asthma a year is saving 25 classrooms for students from chronic lung disease. Children should not have to suffer from illness for the rest of their lives because of where they live or where they are schools.”

Lang is a PhD. Candidate for the Department of Earth, Environment and Planetary Sciences in the Northwest. College of Arts and Sciences. She is advised by Daniel Horton, an associate professor of Earth, Environment and Planetary Science, a senior author of the study. Insights from members of the Respiratory Hygiene Association, Warehouse Workers for Justice, Little Village Environmental Justice Organization, and other Net-Z Union members helped inform the research.

It affects air pollution

Exposure to traffic-related pollutants is associated with many myriad healthy health outcomes, including asthma, emphysema, chronic bronchitis and ultimately early death. To combat these issues, California adopted the ACT policy in June 2020. Several other states have followed suit since. The intervention policy aims to gradually replace approximately 50% of on-road and heavy vehicles such as trucks and buses by 2050.

“ACT aims to reach around 50% of the ZEV fleet by 2050, as truck carriers have the economics to consider,” says Horton. “They cannot effectively replace diesel fleets overnight. However, the action is gradually adopted for zero-emission vehicles, as the vehicle age and the company needs to update the fleet.”

Whether a similar policy would help control pollution-related health risks in the Chicago area, Net-Z Illinois members approached the Houghton lab in Northwestern. The Horton group previously modeled an aviation quality scenario in which 30% of current on-road heavy duty vehicles in the Chicago area have moved to electric versions. His lab previously looked at how contamination differed from neighborhood to neighborhood. After reviewing these studies, community members noticed some important gaps in the data.

“The community asked if they could simulate the effectiveness of ACT policies, so they can now advocate for it in Illinois,” said Horton, who heads the Climate Change Research Group in Northwestern. “But they also suspected we were wrong about emissions data in certain parts of the city. So first we had to understand that.”

Community Groups Fill in the blank

In Horton’s air quality model, his team draws data from the EPA. This provides a significant national emission estimate. These estimates are designed for wide applicability and may not capture local variations of the emission patterns.

“To determine emissions nationwide, the EPA will select representative counties that may include Chicago,” Horton explained. “They assign typical emission levels based on factors like traffic, road type, population density, and so on. That’s useful, but they’re not custom designed in Chicago.”

“The default EPA model also uses coarser resolution,” added Lang. “We can run the model at a kilometer resolution and acquire local influences at nearby scales. However, some assumptions used at coarser resolutions may not be converted to high-resolution applications either.”

Community partners living in Chicago’s West Side have noticed that the emissions contained in previous models appear to be low. To explore this intuition, citizen scientists deployed 35 track count cameras at intersections along the I-55 corridor. Cameras revealed that communities along I-55 southwest of downtown Chicago often experience thousands of truck aisles per day. Over the road, heavy-duty trucks are often idle during long periods of loading and unloading of driveways, pickup lines and cargo. These idling episodes were underrated by the data.

“We tried to match the models to those living experiences,” Lang said. “We found that by distributing them throughout the city, the EPA simulates short idling from heavy-duty vehicles. We knew that these vehicles were not representative of where they operate, which is mainly located near warehouses and distribution centers on the west side of Chicago.

Health and economic benefits of ZEV adoption

After augmenting the model with this new information, the researchers performed baseline simulations to create a complete, high-resolution snapshot of current air pollution in Cook County and its surrounding Collar County. According to this baseline simulation, tailpipe exhaust from medium and heavy-duty vehicles contributes approximately 22% of NO2 contamination. This is linked to new cases of 1,330 premature births and 1,580 pediatric asthma per year.

To simulate pollution after adopting ACT regulations, the team removed tailpipe emissions from almost 50% of medium and heavy-duty vehicles. The researchers then compared current pollution to predicted levels of pollution in the 2050s based on ACT policies. If Illinois adopts the policy, by 2050, NO2 levels will decline by 8.4% across the region, they found. This decrease results in fewer deaths of premature births per year, and fewer new cases of pediatric asthma per year.

Beyond health benefits, adopting ACT regulations in Illinois will have great benefits to addressing the economy and longstanding systematic pollution exposure gaps. The research authors estimate that Illinois could save $731 million a year to avoid health costs and climate damage. In many cases, communities of colour live near major roads and warehouses where truck traffic is heaviest, are disproportionately affected by current levels of pollution. Therefore, these communities experience the greatest improvements.

As the Illinois Pollution Prevention Commission is considering proposals to adopt legal policies, the new study highlights the specific importance of adopting ZEVs to improve public health for Illinois residents. Professor Robert Weinstock of Northwestern Pretzker School was a key attorney for a community group urging the board to adopt the measure, while Horton provided expert testimony on the projected public health benefits from vehicle electrification in Illinois. This study illustrates the unique and powerful real-world impact of community-academic collaboration.

“Ultimately, it’s up to the individual states to adopt ACT standards,” Houghton said. “This is an opportunity for Illinois to lead by adopting good policies for both Illinois health and global climate.”