Agricultural burning in Imperial Valley, California and respiratory symptoms in children: a cross-sectional, repeated measures analysis

Abstract

Background and Aim: The open burning of agricultural fields after harvesting is an under-recognized and understudied source of air pollution in rural communities. Smoke from agricultural burning contains air toxics that may adversely impact respiratory health. Imperial County in southeastern California is a highly productive agricultural valley that heavily employs agricultural burning. We investigated associations between individual-level exposure to agricultural burning and parent-reported respiratory symptoms in children. Methods: We leveraged the Children’s Assessing Imperial Valley Respiratory Health and the Environment cohort of 744 elementary school students in five predominantly Hispanic low-income communities in Imperial County. Parents reported children’s respiratory health symptoms and family demographic characteristics in questionnaires collected at enrollment and in annual follow-up assessments from 2017-2021. Permitted agricultural burns in Imperial County from 2016-2021 were spatially linked to children’s geocoded residential addresses. We used generalized estimating equations to evaluate associations between repeated measures of respiratory symptoms and exposure to agricultural burning within 5 km in the 12 months prior to each assessment. Results: Two-thirds (495, 68%) of children lived within 5 km of at least one agricultural burn during the study period. Children exposed to agricultural burns were generally similar to unexposed children. After adjustment for language of parent questionnaire, health insurance, child sex, grade, school, and asthma diagnosis at baseline, children living within 5 km of agricultural burning had greater odds of reported bronchitis (OR 4.30, 95% CI 1.74-10.7), bronchitic symptoms (OR 1.98, 95% CI 1.16-3.40), and asthma medication use (OR 1.90, 95% CI 0.96-3.76), compared to unexposed children. Conclusions: To our knowledge, this is the first U.S. study of agricultural burning and children’s respiratory health. This work suggests that reducing agricultural burning could improve children’s respiratory health. Further research quantifying how air toxics may mediate the observed associations is forthcoming. Keywords: agricultural burning, children, respiratory, geospatial