Effect of Personal Exposure to PM 2.5 on Respiratory Health in a Mexican Panel of Patients with COPD

Background : Air pollution is a problem, especially in developing countries. We examined the association between personal exposure to particulate matter with an aerodynamic diameter less than 2.5 µm (PM 2.5 ) on respiratory health in a group of adults with chronic obstructive pulmonary disease (COPD). Methods : All participants resided in Mexico City and during follow-up, personal exposure to PM 2.5 , respiratory symptoms, medications, and daily activity were registered daily. Peak expiratory flow (PEF) was measured twice daily, from February through December, 2000, in 29 adults with moderate, severe, and very severe COPD. PEF changes were estimated for each 10 µg/m 3 increment of PM 2.5 , adjustment for severity of COPD, minimum temperature, and day of the sampling. Results : For a 10-µg/m 3 increase in the daily average of a two-day personal exposure to PM 2.5 , there was a significant 33% increase in cough (95% CI, range, 5‒69%), and 23% in phlegm (95% CI, range, 2‒54%), a reduction of the PEF average in the morning of −1.4 L/min. (95% CI , range, −2.8 to −0.04), and at night of −3.0 L/min (95% CI, range, −5.7 to −0.3), respectively. Conclusions : Exposure to PM 2.5 was associated with reductions in PEF and increased respiratory symptoms in adults with COPD. The PEF reduction was observed both at morning and at night.