The study on association between air pollution and outpatient department visits and mortality in Thailand

Abstract

This study aimed to investigate the association between air pollutants (NO2, O3, PM10 and PM2.5) and outpatient department visits and mortality in Thailand. Daily average concentration data for NO2, O3, PM10 and PM2.5 as well as meteorological data (temperature and relative humidity) from all available monitoring stations in Thailand was obtained from the Pollution Control Department. The daily number of outpatient department (OPD) visits data for respiratory (ICD10: J00-J99) and cardiovascular (ICD10:I00-I99) diseases under the Universal Health Coverage scheme was obtained from the National Health Security Office in the same period and the daily number of non-accidental mortality (ICD10: A00-R99) wasobtainedfrom the Strategyand Planning Divisionunder theMinistryof Public Healthduring1 January 2016 through 31 December 2020. Time-series analysis with quasi-Poisson regression model was applied to investigate the province-specific association of individual air pollution with OPD visits and mortality. Then, province-specific estimates were pooled to derive the relative risk (RR) as the national effects of individual air pollution on OPD visits and mortality using the multivariate meta-analysis. Findings from this study showed that there were the association between NO2 , PM10 and PM2.5 among OPD visits was the highest at current day (lag 0), whereas that of O3 was peaked at lag 1 day. The relative risk (RR) of OPD visits per 10 ppb increase in NO2 was 1.0533 (95% CI: 1.0386, 1.0682) and RR per 10 µg/m3 increase in PM10 and PM2.5 was 1.0119 (95% CI: 1.0083, 1.0156) and 1.0123 (95% CI: 1.0065, 1.0182), respectively. The RR per 10 ppb increase in O3 was 1.0100 (95% CI: 1.0003, 1.0198) at lag 1 day. Moreover, the effect of NO2, PM10 and PM2.5 on non-accidental mortality was the highest at current day (lag 0), whereas that of O3 was peaked at lag 4 days. The RR of non-accidental mortality per 10 ppb increase in NO2 and O3 was respectively 1.0302 (95% CI: 1.0188, 1.0418) and 1.0100 (95% CI: 1.0030, 1.0171) and RR per 10 µg/m3 increase in PM10 and PM2.5 was 1.0092 (95% CI: 1.0061, 1.0122) and 1.0220 (95% CI: 1.0142, 1.0298), respectively. In summary, this study found that increased air pollution levels were associated with an increase in the number of outpatient services and the number of deaths in Thailand. Therefore, policy recommendations should be made to reduce sources of air pollution seriously and raise public awareness on health impact prevention to reduce illness and death as well as to create a good quality of life for Thai population.