Contributions of Biomass Burning Events to Daily PM10 Concentrations and The Short-Term Associations with Hospital Admissions in Malaysia

Abstract

Background and Aim: Despite serious biomass burning in the Southeast Asian region, there is a lack of epidemiological studies that directly evaluate the health effects of particulate matter attributed to biomass burning. This study aims to estimate the short-term effects of particulate matter ≤10µm (PM₁₀) on hospital admissions in Peninsular Malaysia, distinguishing between PM₁₀ originating from biomass burning and other sources. Methods: We identified biomass burning by evaluating daily hotspot information from MODIS satellite sensor and the HYSPLIT backward wind trajectories at five districts during 2005 – 2015. Days with wind trajectories passing through biomass burning were known as "haze days”. We estimated PM₁₀ concentrations attributed to biomass burning by decomposing total concentrations using the moving mean of PM₁₀ on non-haze days. We fitted district-specific quasi-Poisson regression models to estimate associations of PM₁₀ attributable to biomass burning and non-biomass burning with daily hospitalizations due to respiratory and cardiovascular diseases (ICD-10: J00-J99 and I00-I99, respectively). To obtain a regional average, we pooled district-specific results using random-effects meta-analysis. Results: We analyzed respiratory (210,960 cases) and cardiovascular (178,952 cases) hospitalizations. On average, 50% of study period was identified as haze days (PM₁₀ due to biomass burning >0µg/m³). Average PM₁₀ levels attributed to biomass burning and non-biomass burning were 6.6µg/m³ (SD: 51.7) and 41.6µg/m³ (SD: 20.6) respectively. Increases of 10µg/m³ biomass burning PM₁₀ and non-biomass burning PM₁₀ during non-haze day (lag 0–1 days) were associated with increases in respiratory hospital admissions of 0.44% (95% CI: 0.06, 0.82%) and 0.86% (95% CI: 0.31, 1.41%), respectively. We could not see any significant associations for cardiovascular hospital admissions. District-specific estimates of the associations appeared to be homogeneous. Conclusions: PM₁₀ from both biomass burning and other emission sources were positively associated with respiratory hospitalizations in Peninsular Malaysia. Keywords: Biomass burning event, Particulate matter, Hospital admission, Respiratory disease