タイ北部における野焼き由来の粒子状物質、および煙霧コントロールのための規制介入の健康インパクト

京都大学新制・課程博士博士(工学)甲第23493号工博第4905号新制||工||1766(附属図書館)京都大学大学院工学研究科都市環境工学専攻(主査)教授 高野 裕久, 教授 米田 稔, 准教授 上田 佳代学位規則第4条第1項該当Doctor of Philosophy (Engineering)Kyoto UniversityDFA

Estimation of hospital visits for respiratory diseases attributable to PM10 from vegetation fire smoke and health impacts of regulatory intervention in Upper Northern Thailand

The air quality in Upper Northern Thailand (UNT) deteriorates during seasonal vegetation fire events, causing adverse effects especially on respiratory health outcomes. This study aimed to quantitatively estimate respiratory morbidity from vegetation fire smoke exposure, and to assess the impact of a burning ban enforced in 2016 on morbidity burden in UNT. We computed daily population exposure to fire-originated PM10 and estimated its health burden during a 5-year period from 2014 to 2018 using daily fire-originated PM10 concentration and the concentration-response function for short-term exposure to PM10 from vegetation fire smoke and respiratory morbidity. In subgroups classified as children and older adults, the health burden of respiratory morbidity was estimated using specific effect coefficients from previous studies conducted in UNT. Finally, we compared the health burden of respiratory morbidity before and after burning ban enforcement. Approximately 130,000 hospital visits for respiratory diseases were estimated to be attributable to fire-originated PM10 in UNT from 2014 to 2018. This estimation accounted for 1.3% of total hospital visits for respiratory diseases during the 5-year period, and 20% of those during burning events. Age-specific estimates revealed a larger impact of PM10 in the older adult group. The number of hospital visits for respiratory diseases attributable to fire-originated PM10 decreased from 1.8% to 0.5% after the burning ban policy was implemented in the area. Our findings suggest that PM10 released from vegetation fires is a health burden in UNT. The prohibition of the burning using regulatory measure had a positive impact on respiratory morbidity in this area

Association between PM₁₀ from vegetation fire events and hospital visits by children in upper northern Thailand

Few studies have focused on the effects of exposure to air pollutants from vegetation fire events (including forest fire and the burning of crop residues) among children. In this study we aimed to investigate the association between PM₁₀ concentrations and hospital visits by children to address respiratory disease, conjunctivitis, and dermatitis. We examined and compared these associations by the presence of vegetation fire events on a given day (burning, non-burning, and mixed) across the upper northern region of Thailand from 2014 through 2018. A vegetation burning was defined when a fire hotspot (obtained from NASA-MODIS) exceeded the 90th percentile of the entire region and PM₁₀ concentration was over 100 μg/m³. To determine the association between hospital visits among children with PM₁₀ concentrations on burning and non-burning days, we performed a time-stratified case-crossover analysis fitted with conditional logistic regression for each province. A random-effects meta-analysis was applied to pool province-specific effect estimates. The number of burning days ranged from 64 to 139 days across eight provinces. A 10 μg/m³ increase in PM₁₀ concentration on a burning day was associated with a respiratory disease-related hospital visit at lag 0 (OR = 1.01 (95% CIs: 1.00, 1.02)). This association was not observed for hospital visits related to conjunctivitis and dermatitis. A positive association was also observed between PM₁₀ concentration on non-burning days and hospital visits related to respiratory disease at lag 0 (OR = 1.03 (95% CIs: 1.02, 1.04)). Hospital visits for conjunctivitis and dermatitis were significantly associated with PM₁₀ concentration at lag 0 on both non-burning and mixed days

Association between Long-Term Ambient PM2.5 Exposure and under-5 Mortality: A Scoping Review

Studies have established a link between exposure to fine particles (PM2.5) and mortality in infants and children. However, few studies have explored the association between post-birth exposure to PM2.5 and under-5 mortality. We conducted a scoping review to identify relevant epidemiological evidence on the association between post-birth ambient PM2.5 exposure and under-5 mortality. We searched PubMed and Web of Science for articles published between 1970 and the end of January 2022 that explicitly linked ambient PM2.5 and under-5 mortality by considering the study area, study design, exposure window, and child age. Information was extracted on the study characteristics, exposure assessment and duration, outcomes, and effect estimates/findings. Ultimately, 13 studies on infant and child mortality were selected. Only four studies measured the effect of post-birth exposure to PM2.5 on under-5 mortality. Only one cohort study mentioned a positive association between post-birth ambient PM2.5 exposure and under-5 mortality. The results of this scoping review highlight the need for extensive research in this field, given that long-term exposure to ambient PM2.5 is a major global health risk and child mortality remains high in some countries