Ambient PM_2.5 in the residential area near industrial complexes: Spatiotemporal variation, source apportionment, and health impact

This study systemically investigated the ambient PM_2.5 (n = 108) with comprehensive analyses of the chemical composition, identification of the potential contributors, and estimation of the resultant respiratory physician visits in the residential regions near energy-consuming and high-polluting industries in central Taiwan. The positive matrix fraction (PMF) model with chemical profiles of trace metals, water-soluble ions, and organic/elemental carbons (OC/EC) was applied to quantify the potential sources of PM_2.5. The influences of local sources were also explored using the conditional probability function (CPF). Associations between the daily PM_2.5 concentration and the risk of respiratory physician visits for the elderly (≥ 65 years of age) were estimated using time-series analysis. A seasonal variation, with higher concentrations of PM_2.5, metals (As, Cd, Sb, and Pb), OC/EC and ions (i.e., NO^3 −, SO₄^2 − and NH₄⁺) in the winter than in the spring and summer, was observed. Overall, an increase of 10 μg m^− 3 in the same-day PM_2.5 was associated with an ~ 2% (95% CI: 1.5%–2.5%) increase in respiratory physician visits. Considering the health benefits of an effective reduction, we suggest that the emission from coal combustion (23.5%), iron ore and steel industry (17.1%), and non-ferrous metallurgy (14.4%), accounting for ~ 70% of the primary PM_2.5 in the winter are prioritized to control.