Garcia E, et al. - In this longitudinal study involving 4140 children with no history of asthma, researchers ascertained if decreasing regional air pollutants were correlated with decreased incidence of childhood asthma. According to findings, declines in ambient nitrogen dioxide and PM_2.5 were significantly linked to a lower incidence of asthma among children in Southern California between 1993 and 2014. No statistically significant associations with ozone and particulate matter change of less than 10 μm existed.