(JAMA) The study investigated the relationship between regional air pollutants and the incidence of childhood asthma. The study followed 4140 children over a period of air pollution decline in Southern California and collected data on incident asthma through questionnaires. The results showed that a decrease in ambient nitrogen dioxide and PM2.5 was significantly associated with a lower incidence of asthma.
Garcia E, Berhane KT, Islam T, et al. (2019) Association of Changes in Air Quality With Incident Asthma in Children in California, 1993-2014. JAMA. 321(19):1906–1915. https://jamanetwork.com/journals/jama/article-abstract/2733972