Just How Hazardous is it to Live by a Freeway? UC Merced Researchers Issue Report for Fresno

By Patty Guerra, UC Merced

July 1, 2024

The study is a basis for a proposal to change trucking routes.

When the city of Fresno and the San Joaquin Valley Air Pollution Control District wanted specifics about the impacts of truck traffic on the health of some of the city's most vulnerable residents, officials turned to UC Merced's Community Labor Center (CLC) and public health Professor Sandie Ha.

Ha has extensive experience in conducting population-based studies on environmental impacts of health. She and a team of researchers crafted an assessment of environmental health for the greater Fresno community. The study, published in April, is the basis for a proposal to change trucking routes through town.

The state has identified a community in south Fresno as being disproportionately impacted by air pollution due to the presence of industrial activities of businesses and other pollution sources, Ha said.

"Living closer to highways, major roads, truck routes, and other pollution sources is known to be related to higher air pollution exposures (and other types of pollution such as noise and light), which have well-established health effects," she said.

According to the study, south Fresno residents live an average of 843 feet from a heavily traveled truck route, compared with 1,267 feet for other Fresno residents, and are exposed to twice the amount of diesel fumes.

Researchers hypothesized that health risk would be higher in south Fresno, but the magnitude of the differences was a surprise.

"The differences we observed in terms of adverse pregnancy outcomes and asthma are larger than I thought, necessitating prompt actions to reduce the gap," Ha said. "We also observed seasonal differences in how air pollution may impact health."

The report stated that south Fresno's proximity to truck routes is linked to a 44% increase in infant mortality risk for Fresno mothers and an 11% jump in preterm births. For babies living within 1,000 feet of a freeway, the risk of dying before their first birthday rises 23%. Researchers also found increased incidences of cardiovascular diseases among these residents. In a story about the report, nonprofit news organization Fresnoland called the findings "staggering".

And the health impacts could be escalating.

Sociology Professor Edward Flores, faculty director of the CLC, said it's vital that governments use the report's findings to make decisions about how and where businesses can expand and the nature and location of truck routes that serve them.

"The development that's under way is still not complete," he said. "There's risk that if the expansion that's being proposed were to occur without mitigating the hazards of trucks driving through residential neighborhoods, people's health would get worse."

The UC Merced report was used to develop a proposal to reroute truck traffic away from neighborhoods. The report is set to be presented to the Fresno City Council in July.

"This study highlights why reinforcing and expanding policies to further reduce emissions are important strategies to reduce climate change's impacts on pregnancy health and why continuing climate change funds for south Fresno and similar communities is critical," Ha said. "We would like to see truck routes being redirected away from residential areas and sensitive receptors such as schools, daycares, and hospitals. Where rerouting is not possible, efforts should be made to regulate truck activities to reduce pollution and other related risks. "

The report recommends the city implement zero-emission commercial trucks to reduce additional emissions into an already burdened area. The California Air Resources Board's requirement that large companies convert to zero-emission trucks by 2042 is an important step to reduce the impact of air pollution. Immigrant and small-fleet operators who face financial and language barriers to access state financial support will also need to be included in the transition, the report recommends.

The study also advances one of the main goals of the university.

"UC Merced was founded with the mission of placing a world-class public research institution in the central San Joaquin Valley region," Flores said.

Patty Guerra