Effect of air pollution on health care expenditure: Evidence from respiratory diseases
利用台湾2006-2012年全民健康保险数据，以热逆温现象作为工具变量，估计空气质量指数每降低1个单位每年可节省23亿新台币的呼吸系统门诊支出，完全消除污染可减少约8%的国民医疗支出。
Recent reports show that at least 95% of the world's population is breathing polluted air. However, the impact of air quality on air pollution-related medical expenditure and utilization is sparse. This study estimates the short-term health care cost impacts of air pollution using a meteorological phenomenon-thermal inversion-as an instrumental variable for air quality. Using information on outpatient care for respiratory diseases from universal health insurance claim data in Taiwan during 2006-2012, our estimates suggest that a one-unit reduction in the air quality index (AQI) leads to NT$2.3 billion (nearly US$74 million) of savings in respiratory-related outpatient expenditure per year. Given that the average AQI is equal to 32 during our study period, completely removing air pollution would reduce the national health expenditure by approximately 8% annually. Our results provide the important implication that the cost of controlling air pollutant emissions can be offset by curtailing health care expenditure.