Air pollution exposure and health impacts in the Kathmandu valley

Abstract

Air pollution monitoring in Kathmandu valley during 2003-2007, 2014-2015 and 2017 onwards shows that there has been substantial decrease in particulate air pollution with around 50% reduction in overall average PM10 from 123 μg/m3 for the period 2003-2007 to 61μg/m3 during 2018-2020 equivalent to around 3.2% decrease per year from 2003 to 2020. Similarly, a reduction of 13.6% in PM2.5 from 49 μg/m3 during 2014/15 to 42.4 μg/m3 during 2017-2020 was found with around 4.2% decrease per year from 2014-2015 to 2020. However, the averages are still 3-4 times higher than WHO 2005 guideline values and pose serious threats to the valley inhabitants. Assessment of respiratory health burdens like chronic obstructive pulmonary disease and acute respiratory infection including pneumonia showed 6%-13% of the respiratory morbidities can be attributed to PM2.5 in Kathmandu valley. Under 35% PM2.5 reduction scenario in 2030, the expected avoidable fractions are found to be 2.5-4.9%.