ANALYSIS OF AMBIENT PARTICULATE AIR POLLUTION AND HEALTH IN NEPAL

Air quality has been a major environmental and public health concern in Nepal. Currently, air pollution monitoring is ongoing at 28 monitoring stations in all the provinces and 19 districts of Nepal. Available daily air pollution data (PM2.5) was collected for 21 stations spread across 6 provinces (except Sudorpaschim) and 14 districts for around two and half years from 2019 till May 2021. Similarly, annual outpatient respiratory and cardiovascular disease morbidity was obtained for 2018/19-2019/20 for the districts where air pollution data was available. Descriptive and discriminant analysis were performed to assess air pollution situation and classification characteristics of Nepal. Overall, annual average of Nepal assessed by PM2.5 has decreased from 37.8 µg/m3 in 2019 to 35.8 µg/m3 in 2020 but has again unexpectedly and substantially risen to 56.5 µg/m3 in 2021 (Till May) primarily due to large scale forest fires that occurred at many places of Nepal which peaked at the end of March, 2021. Provincial averages for the study period showed Province 2 to be the highest air polluted province (58.9 µg/m3) and Karnali as the least air polluted province (30.5 µg/m3) which implied that the averages are 3.5 to 5.9 times higher than the WHO annual guideline of 10 µg/m3 for PM2.5. The canonical discriminant function showed highest discriminant coefficient for Province 2 (0.54) followed by Province 1 (0.13), Bagmati (0.02), Lumbini (-0.18), Gandaki (-0.20) and Karnali (-0.25). Highest attributable factor associated with PM2.5 is obtained for Pneumonia (0.108), followed by COPD (0.053) and respiratory (0.033). The corresponding annual attributable burden is found to be highest for Respiratory (1.66 Lakhs) followed by Pneumonia (0.35 Lakh) and COPD (0.2 Lakh) morbidities. In conclusion, air quality situation in Nepal is still a major environmental and public health hazard which requires further steps and efforts to reduce it in the coming years.