Agricultural Burn Smoke Linked to Children’s Respiratory Health

Exposure to smoke from agricultural burns for as little as two weeks per year may worsen children’s respiratory health outcomes, a team of researchers and community partners found. The team, composed of researchers from the University of Southern California and community leaders from the Comité Civico del Valle, started the Children’s Assessing Imperial Valley Respiratory Health and the Environment (AIRE) study in response to community concerns about children’s respiratory health in Imperial Valley, a rural area in southern California. A July 2023 paper describes the AIRE cohort and how agricultural burning may be linked to wheezing and coughing in children.

Previous work in the Imperial Valley has looked at the effects of the shrinking Salton Sea on children’s health, but the AIRE cohort takes a wider look at how overall exposure to air pollution, including from agricultural sources, contributes to children’s health disparities in a region where asthma is prevalent.

“This is the first study in the U.S. to examine the effects of agricultural burning on children’s respiratory health,” stated Elizabeth Kamai, Ph.D., a researcher on the study. “Even though these burns are localized and don’t last very long, they can have a noticeable impact on nearby air quality. Our data supports the hypothesis that this source of air pollution can impact children’s health, especially for kids with asthma.”

“It is also an environmental justice issue because these children are adversely affected by asthma and other socioeconomic issues, including high rates of poverty, and they have this harmful environmental exposure on top of that,” stated Shohreh Farzan, Ph.D., lead researcher of the AIRE study.

Proximity to Agricultural Burning Linked to Children’s Breathing Problems

Smoke from agricultural burning contains particulate matter that can have harmful effects on health. The Imperial Valley had 906 permitted agricultural burns from 2016 to 2019. These burns often occurred within several miles of schools and children’s homes, creating an environmental justice issue for the majority Hispanic region where 1 in 3 children live in poverty and 1 in 5 children have been diagnosed with asthma.

“Our work at Comité Civico del Valle aims to get to the heart of our community’s concerns, and a large portion of our work is directed toward addressing environmental health concerns,” said Luis Olmedo, executive director of Comité Civico del Valle. “Working with the research team on the AIRE study is an exciting project for us to find out more about what is going on with children’s respiratory health, and to get that information back in the hands of the community.”

Comité Civico del Valle’s connections with the community facilitated the relationship between the research team and local elementary school administrators who agreed to support the study. The team enrolled 708 first, second, and third grade students from five elementary schools across the region from 2017 to 2019. Parents were given surveys at the beginning of the study, and again twice a year for two years. The surveys asked parents to reflect on their children’s health over the past year, including asthma, respiratory symptoms such as wheezing or persistent cough, allergies, physical activity, and eye irritation.

Using the children’s addresses and records from agricultural burn permits, researchers determined how far each child lived from burn events and for how many days they were exposed to smoke from the burns. Analyzing this data in the context of the parents’ survey results, they found that children exposed to burns for the longest amount of time (4-13 days over the year) had significantly greater reported wheezing symptoms than children exposed to burns for 3 or fewer days. Researchers also determined that children with asthma exposed to smoke from burns had far greater reports of wheezing and sneezing than children with asthma who were not exposed to burns, supporting the idea that exposure to agricultural burns worsened asthma symptoms.

The research team developed a story map, which provides context for study results, such as details about agricultural burning and a map of burn locations relative to elementary schools.

Future Directions for the AIRE Study

The AIRE study emphasizes community engagement and reporting back results. Study partners have discussed results with residents and have developed communication materials to get information to the community.

The AIRE team also plans to establish an advocacy program to support community organizations and residents in addressing environmental health disparities. Agricultural burning is inexpensive, and farmers in Imperial Valley do not receive financial support from the state to transition to other methods for disposing of waste. Through advocacy, the partners hope to encourage farmers to use alternative methods that produce less particulate matter, such as tilling or mulching.

“We look forward to continuing to support the community with research that directly responds to their environmental health concerns,” added Farzan. “The partnership with Comité Civico del Valle has provided the opportunity to dive deep into environmental justice issues in the community and to support actions that can begin to address these concerns.”