This paper aims to analyze the effectiveness of California's Clean Air regulations. Using historical data on infant birthweights from the NCHS, a Difference in Differences (DID) model will demonstrate changes in birthweight after the enforcement of a 1988 regulation. The regulation analyzed affected new cars, mandating that manufacturers install on-board diagnostics (OBD) systems on all new vehicles in the state. In the case of the DID, California acts as the treatment, and the neighboring states will act as controls. This is due in part to limitations in the data with regional variables. The analysis also aims to measure the effectiveness of the policies on the basis of environmental indicators as well. This data was made publicly available by the EPA. These variables measure levels of nitrogen dioxide (NO2) and carbon monoxide (CO) levels. The findings of this research conclude that the enactment of this regulation may have had positive short-term effects on air quality as well as infant birthweight. There exist further opportunities to delve into this research looking at either a longer period or using more specific regional variables than made publicly available in the aforementioned data sets.
