  This study investigates the impacts of the Automobile NOx Law of 1992 on
ambient air pollutants and fetal and infant health outcomes in Japan. Using
panel data taken from more than 1,500 monitoring stations between 1987 and
1997, we find that NOx and SO2 levels reduced by 87% and 52%, respectively in
regulated areas following the 1992 regulation. In addition, using a
municipal-level Vital Statistics panel dataset and adopting the regression
differences-in-differences method, we find that the enactment of the regulation
explained most of the improvements in the fetal death rate between 1991 and
1993. This study is the first to provide evidence on the positive impacts of
this large-scale automobile regulation policy on fetal health.
