Effect of indoor coarse particulate matter on blood pressure and lung function of male patients with chronic obstructive pulmonary disease: Perspectives of constituent, source and season

Background: Evidence regarding the cardiopulmonary effects of indoor coarse particulate matter (PM2.5-10) and its chemical constituents and sources remains limited. Methods: Five consecutive daily visits (200 person-visits in total) were completed among 40 male patients with chronic obstructive pulmonary disease (COPD) in this panel study from November 2015 to May 2016 in Beijing, China. Daily indoor PM2.5-10 was collected and twenty-one elements were measured using inductively coupled plasma mass spectrometry. Lung function and blood pressure were measured at daily visit. Principal component analysis (PCA) was used for source appointment. Bayesian kernel machine regression (BKMR) and linear mixed-effect models were used to establish the exposure-response relationships. Results: An interquartile range (IQR, 23.12μg/m3) increase in 1-day average concentration of indoor PM2.5-10 was associated with changes of 0.88 (95CI: -0.25, 2.01) mmHg in systolic blood pressure (SBP), 1.15 (95CI: 0.25, 2.06) mmHg in diastolic blood pressure (DBP), -2.29% (95CI: -4.07%, -0.51%) in forced expiratory volume in the first second (FEV1) and -1.68% (95CI: -3.41%, 0.06%) in peak expiratory flow (PEF). According to the results of PCA, soil/dust, coal combustion, and natural Ni/Cr sources were identified as three main sources of indoor PM2.5-10 inorganic elements. BKMR analysis revealed a significant association of all measured constituents with elevated SBP and a negative trend of FEV1. Coal combustion-related constituents posed a stronger joint effect on blood pressure than the other two sources. Stronger associations of indoor PM2.5-10 constituents with elevated blood pressure and decreased PEF were observed during the heating period than during the non-heating period. And the adverse effects of coal combustion-related constituents on blood pressure and lung function were also stronger in the heating season. Conclusions: Indoor PM2.5-10 constituents were associated with impaired cardiopulmonary health of COPD patients, and those from coal combustion source may play a dominant role, especially during the heating period.