Indoor air pollution and Kathmandu air problems

Indoor air pollution

Indoor air pollution is the presence of harmful gases and particles in the air inside buildings (homes, schools, offices). Main sources are burning of firewood, dung, crop waste and kerosene for cooking and heating in poorly ventilated kitchens, tobacco smoke, incense, paints and mould. Key pollutants are PM2.5, carbon monoxide, formaldehyde and NO₂. In Nepal it mainly affects rural women and children, causing pneumonia, COPD, eye disease and low birth weight.

Severity of environmental and health problems due to air pollution in Kathmandu

Kathmandu valley is one of the most polluted urban areas of South Asia. Annual average PM2.5 is several times the WHO guideline, and in winter and spring the AQI often reaches the "unhealthy" to "hazardous" range.

Causes in brief: vehicle exhaust, road and construction dust, brick kilns, open waste burning, industries, forest fires and trans-boundary haze, made worse by the bowl-shaped valley and winter temperature inversion.

Health problems

1. Respiratory disease – asthma, bronchitis, COPD and pneumonia; hospitals report more patients in the dry season.
2. Cardiovascular disease – PM2.5 enters the blood and increases heart attacks and strokes.
3. Lung cancer risk increases with long-term exposure.
4. Eye, nose and throat irritation, headache, fatigue.
5. Vulnerable groups – children, elderly, pregnant women, traffic police and street vendors are most affected; children's lung growth is reduced.
6. Lower life expectancy – studies estimate that air pollution cuts several years of life for valley residents and is a top risk factor for death in Nepal.

Environmental problems

1. Smog and poor visibility – flights at Tribhuvan International Airport are delayed; mountain views are lost, hurting tourism.
2. Damage to heritage – soot and acidic gases blacken and corrode temples, statues and buildings of the World Heritage Sites.
3. Vegetation damage – dust on leaves reduces photosynthesis; ozone harms crops.
4. Climate impact – black carbon and CO₂ add to warming; black carbon deposited on Himalayan snow speeds melting.
5. Acid deposition from SO₂ and NOₓ.
6. Economic loss – medical costs, lost work days and reduced tourism.

Measures: electric public transport, emission testing, dust control, cleaner brick kilns, ban on open burning, green spaces and air quality monitoring with public warnings.