Association between out-patient visits and air pollution in Chiang Mai, Thailand: Lessons from a unique situation involving a large data set showing high seasonal levels of air pollution

Abstract

Chiang Mai is one of the most known cities of Northern Thailand, representative for various cities in the East and South-East Asian region exhibiting seasonal smog crises. While a few studies have attempted to address smog crises effects on human health in that geographic region, research in this regard is still in its infancy. We exploited a unique situation based on two factors: large pollutant concentration variations due to the Chiang Mai smog crises and a relatively large sample of out-patient visits. About 216,000 out-patient visits in the area of Chiang Mai during the period of 2011 to 2014 for upper (J30-J39) and lower (J44) respiratory tract diseases were evaluated with respect to associations with particulate matter (PM10), ozone (O3), and nitrogen dioxide (NO2) concentrations using single-pollutant and multiple-pollutants Poisson regression models. All three pollutants were found to be associated with visits due to upper respiratory tract diseases (with relative risks RR = 1.023 at cumulative lag 05, 95% CI: 1.021–1.025, per 10 μg/m3 PM10 increase, RR = 1.123 at lag 05, 95% CI: 1.118–1.129, per 10 ppb O3 increase, and RR = 1.110 at lag 05, 95% CI: 1.102–1.119, per 10 ppb NO2 increase). Likewise, all three pollutants were found to be associated with visits due to lower respiratory tract diseases (with RR = 1.016 at lag 06, 95% CI: 1.015–1.017, per 10 μg/m3 PM10 increase, RR = 1.073 at lag 06, 95% CI: 1.070–1.076, per 10 ppb O3 increase, and RR = 1.046 at lag 06, 95% CI: 1.040–1.051, per 10 ppb NO2 increase). Multi-pollutants modeling analysis identified O3 as a relatively independent risk factor and PM10-NO2 pollutants models as promising two-pollutants models. Overall, these results demonstrate the adverse effects of all three air pollutants on respiratory morbidity and call for air pollution reduction and control.

Decadal Trends in Ambient Air Pollutants and Their Association with COPD and Lung Cancer in Upper Northern Thailand: 2013–2022

“…Findings from a multicenter cohort project study on long-term exposure revealed that even exposure to concentrations less than 20 µg/m 3 led to a rise in mortality rates [30]. In line with our research, studies conducted in northern Thailand have revealed associations between PM 2.5 , PM 10 , and O 3 with COPD [31], leading to increased acute exacerbations and visits to the emergency room [32,33]. The increased rates of COPD re-admission and fatality may be attributed to the impact of PM on pulmonary function [34,35], specifically focusing on forced expiratory volume in one second (FEV 1 ), a primary indicator of COPD fatality.…”

Identifying the determinants of tourism receipts of Thailand and relevant determinant-determinant interactions

“…More precisely, they found that the number of tourist arrivals was inversely proportional to the concentration of particulate matter. This effect is not surprising because there is a continuously growing literature on the negative health effects of particulate matter (see, e.g., Varapongpisan et al [ 53 ], and references therein) such that the general public becomes more and more aware of the negative effects of air pollution. Not only air pollution but all forms of pollutions at a certain destination are likely to scare tourists away from that destination.…”