Air pollution and environmental factors
Particulate matter less than 10 µm (PM10), sulfur dioxide
(SO2), nitrogen dioxide (NO2), ozone
(O3), and carbon monoxide (CO) are factors affecting
COPD exacerbation.7 These air pollutants are known to
have a direct harmful effect or a lag day effect on COPD exacerbation.
Wind speed (WS), solar sunshine (SS), humidity (HM), diurnal temperature
range (DTR) are also important daily ecological factors. In this study,
the lag effect affecting COPD exacerbation was considered using
SO2, NO2, O3, PM10, WS,
SS, HM, CO, and DTR as the main variables.