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

•Indoor PM2.5-10 was associated with impaired cardiopulmonary health of COPD patients.•Soil/dust and coal combustion were two main sources of indoor PM2.5-10 inorganic elements.•Coal combustion-related constituents were closely related to elevated blood pressure.•Adverse cardiopulmonary effects of PM2.5-10 constituents were stronger in the heating season.