Status of Air Pollution over the Last Three Decades in Thimphu City, Bhutan

Abstract

With an increasing human population and vehicles, air pollution in Thimphu City is growing and causing a risk to human health, properties, and ecosystems. The population of Thimphu was 79,185 in 2005 but in 2017 it surged up to 114,551. An increase in the human population has also led to the rising demands for vehicles and thus increased the vehicular emissions in the area. Additionally, the use of traditional fuels, burning of waste and agriculture residues, forest fire, and transboundary pollutants are other sources resulting in poor air quality in Thimphu City. Air pollution data from journal articles, government documents, reports from national and international organizations, and books were reviewed. Concentrations of PM10, PM2.5, SO2, NO2 were increasing over the decades. The annual average PM10 recorded in Thimphu was 28 µg/m3 in 2005, 47 µg/m3 in 2010, 43 µg/m3 in 2014, and 42 µg/m3 in 2015. Winter months were found to have higher PM10 and PM2.5 concentrations. The 24-hourly average concentrations of SO2 ranged from 0.0 to 6.9 µg/m3 and NO2 8.2-26.6 µg/m3. There is a need for comprehensive studies to identify spatial and temporal variations in the ambient concentration of the pollutants in the area. Strict enforcement of the legal frameworks is essential for the mitigation of air pollution in Thimphu City.

Measurement of Indoor Air Pollution in Bhutanese Households during Winter: An Implication of Different Fuel Uses

“…However, R from LPG heaters had positive values that were +0.2550 and +0.6103. This implies that RH values (59, 60) in the LPG household affect the correlation while those of the other households are also affected: kerosene (29,38), wood (34,31), electricity at NEC (52, 54) and at the hospital (32,42), respectively. It should be noted that average Temp in all places was between 17 and 22 • C.…”

“…High PM 10 concentrations were found in the winter months. The main emission sources were from transportation, industry, residential activity, waste generation, agriculture activity, forest fire and transboundary [31].…”

Human health risk assessment of heavy metals in roadside dust near hydropower dams construction areas in Wangduephodrang District of Bhutan

“…Bhutan is known for its natural beauty, rich culture and tradition, and for being one of the few carbon-negative countries in the world (Yangka et al, 2019). However, the country's rapid development and rapid changes in landscape due to developmental activities propelled by population growth remain as major challenge in Bhutan (Sharma et al, 2021). Punatsang Chhu neighborhood has numerous sources of heavy metals in dust from related activities for construction of hydropower projects (PHPA I and II), construction activities, agricultural practices, traffic movements, sand dredging and riverine activities, and land use changes in the district.…”