Indoor pollution and respiratory health in the Himalayas

The exposure to household air pollution due to smoke from open fires and traditional stoves (mainly used in developing countries) can impair respiratory health. Among the indoor pollutants, black carbon (BC) and other co-emitted species have a strong impact on respiratory health, making up a substantial part of indoor pollution. We conducted an interdisciplinary study during winter 2013-2014 in Chaurikharka, a traditional village in the Nepalese Himalayas, aiming at measuring lung function by means of spirometry and 24-hours monitoring indoor air quality, using a portable indoor air-quality system, developed at ISAC-CNR, able to monitor equivalent BC and particle size distribution (300nm to 20µm). We measured lung function in 76 asymptomatic non-smokers (55 F), age 18-85. Bronchial obstruction (FEV1/FVC <0.7) was present in 7.9% of the subjects (26.9% of subjects > 50yrs). FEF25-75 <65% predicted was found in 27.6% (55% of subjects >5 yrs). Monitoring of 32 houses showed BC concentrations > 10 µg/m3 regularly observed during morning and especially evening hours, while night time concentrations are relatively low (0.7 µg/m3). The CO concentrations during the burning of the brazier always exceeded 10 ppm and PM10 reached 1000 µg/m3. FEV1/FVC and FEF25-75% were significantly and inversely correlated to age and to the evening peak of coarse particles emission (p=0.0003, 0.0002, 0.007 and 0.006 respectively). The environmental and health conditions monitored during this study indicate that chronic exposure to indoor pollution definitely impairs respiratory health in dwellers. This impairment is associated with the level and duration of exposure to air pollution and it is also present in asymptomatic subjects.