Institute for Risk Assessment Sciences University.O.Box 80125 TC Utrecht Netherlands;
Department of Occupational and Environmental Health of Public Health University 100191;
Peking University Institute of Environmental Medicine University 100191;
Key Laboratory of Molecular Cardiovascular Sciences of Ministry of Education University 100191;
Department of Respiratory Medicine University Third Hospital 100191;
Section of Environmental Health of Public Health of Copenhagen Copenhagen K;
State Key Laboratory of Environmental Criteria and Risk Assessment Environmental Protection Key Laboratory of Ecological Effect and Risk Assessment of Chemicals Research Academy of Environmental Sciences 100012;
Air filtration; Indoor air pollution; Particulate matter; Cardiovascular benefit; ELDERLY;