Particulate air pollution, birth outcomes, and infant mortality: Evidence from Japan's automobile emission control law of 1992

This study investigates the impacts of the Automobile NO(x) Law of 1992 on ambient air pollutants and fetal and infant health outcomes in Japan. Using panel data taken from more than 1500 monitoring stations between 1987 and 1997, we find that NO(x) and SO(2) levels reduced by 5% and 11%, respectively in regulated areas following the 1992 regulation. In addition, using a municipal-level panel data set from Japan's Vital Statistics Survey and a difference-in-differences approach, we find that the regulation explains most of the improvements in the fetal death rate after the regulation came into effect. This study provides evidence on the positive impacts of this large-scale automobile regulation policy on fetal health.