KATHMANDU: The air quality in Kathmandu, Nepal’s capital, has reached alarming levels, with PM2.5 levels hitting 158 micrograms per cubic meter (μg/m3) as of 9:15 am, according to data from IQ AirVisual.

This places Kathmandu as the 13th most polluted city in the world.

The current PM2.5 concentration is 13.6 times higher than the annual air quality guideline value set by the World Health Organization (WHO).

Causes of pollution in Kathmandu:

Several factors contribute to the heightened pollution levels in Kathmandu, combining both human and geographical elements. The city’s geographical location, nestled within a valley surrounded by mountains and bordered by China and India, plays a role. Additionally, the large number of outdated vehicles, running on obsolete motors and diesel fuels, emit high concentrations of pollutants. Open burning of organic materials and refuse due to inadequate waste management infrastructure further worsens the air quality. The aftermath of earthquakes, construction site dust, and the geographical location exacerbate the accumulation of pollutants, as the city lacks the elevation and wind to disperse them effectively.

Types of pollutants found in Kathmandu:

The pollution in Kathmandu is characterized by fine particulate matter, such as black carbon, resulting from incomplete combustion of fossil fuels, wood, and plants. Outdated vehicles, relying on diesel fuels, emit substantial amounts of black carbon, contributing to air pollution. Other pollutants from vehicles include carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2).

Most polluted months in Kathmandu:

Analysis of 2019 data reveals that the cleanest air quality occurred in August, with a PM2.5 reading of 11.8 μg/m³. In contrast, the months of January to May and November to December experienced the highest pollution levels, reaching a peak in January with a reading of 102.7 μg/m³. Overall, six months of the year recorded unhealthy air quality.

Air quality trends:

Determining whether air quality in Kathmandu is improving remains uncertain, as fluctuations in pollution levels have been observed in recent years. While there was a slight improvement in 2019 with a PM2.5 reading of 48 μg/m³ compared to 2018, it still reflects a decline from 2017 levels. The coming years will provide insights into whether the city’s air quality is genuinely improving or experiencing fluctuations.

Health impacts of air pollution:

Air pollution poses significant health risks, contributing to 7 million premature deaths annually, according to the World Health Organization. It is associated with lung cancer, respiratory infections, stroke, coronary heart disease, and chronic obstructive pulmonary disease. Vulnerable groups, such as those with heart or lung diseases, the elderly, children, pregnant women, outdoor workers, and athletes, are particularly susceptible to severe health effects.

As Kathmandu grapples with environmental challenges amid economic growth, addressing pollution sources like diesel vehicles and open burning may lead to improvements in air quality over time.