1. PM2·5: an important cause for chronic obstructive pulmonary disease?
Chi Pang Wen, Wayne Gao 
The Lancet Planetary Health 
Volume 2, Issue 3, Pages e105-e106 (March 2018)
DOI: /S (18)
Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Terms and Conditions

2. Figure Contribution of risk factors for COPD
(A) Prevalence of smoking, second-hand smoke, and PM2·5 exposure in patients with COPD. Exposure to air pollution is considered ubiquitous, hence prevalence for PM2·5 is 100%. (B) Risk of COPD with exposure to smoking, second-hand smoke, or an increment of 5 μg/m3 in PM2.5. Data in (A) and (B) are from references 4 (PM2·5), 7 (second-hand smoke), and 8 (smoking). (C) We calculated population attributable fractions for each risk factor for COPD from the data in panels (A) and (B) using the formula given in reference 4. COPD=chronic obstructive pulmonary disease. PM2·5=particulate matter with an aerodynamic diameter of 2·5 μm or less.
The Lancet Planetary Health 2018 2, e105-e106DOI: ( /S (18) )
Copyright © 2018 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license Terms and Conditions