Fig. 1. Maps showing (A) the prevalence of chronic cough in general adult populations (reproduced from Song et al., Eur Respir J 2015;45:1479-81, with permission of European Respiratory Society [5]) and (B) modeled annual mean PM2.5 (particulate matter with a diameter of 2.5 μg/m3 or less) for the year 2016 (reprinted from Global ambient air pollution [Internet]. World Health Organization [cited 2018 Mar 20]. Available from: http://maps.who.int/airpollution/).
