WARNING: Breathing is hazardous to health


Two studies published this week show that the air in Kathmandu is even more hazardous to health than previous research showed because of high concentrations of toxic gases, leading to premature deaths from lung diseases.

Dirty air is reducing the lifespan of Nepalis by nearly 7 years in the Tarai, by 3 years in Kathmandu Valley, and Nepal has the highest lung disease death rate in the world, new research papers warn. Another study points to very high concentrations of poisonous nitrous oxides as well as tiny suspended particulates, due to the increase of vehicles in Kathmandu Valley.

Released on 17 August, A State of Global Air Report 2022 zeroes in on two main urban pollutants in over 7,000 cities around the world — particles measuring 2.5μm or less (PM2.5), and nitrogen dioxide (NO2). While Kathmandu is surprisingly not on the list of top 20 most polluted cities, the study shows that the Valley has seen a dangerous increase in the concentration of both pollutants since 2000.

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“Kathmandu does not feature among the cities with the highest PM2.5 levels, but average annual exposures to these dangerously small particles are higher than the WHO Air Quality Guidelines, and even the least stringent interim target of 35 µg/m3,” explains Pallavi Pant of Health Effects Institute which collaborated with Institute for Health Metrics and Evaluation for the annual pollution study. Household fires, brick kilns, open garbage burning and diesel vehicles are primary sources of PM2.5.

Nitrogen dioxide, on the other hand, is a key marker of traffic-related air pollution and is abundant in urban areas like Kathmandu. Nitrogen dioxide belongs to a group of highly reactive nitrogen oxides (NOX) which combine with other gases to form toxic ozone (O3).

“NO2 is a pollutant most closely associated with vehicular traffic, and in Kathmandu the concentration of this gas is higher than other cities in the region like Karachi, Dhaka and Delhi,” warns Pant. “The data indicates the need for continued action to reduce emissions at source."

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Indeed, a 2016 study by the Institute for Advanced Sustainability Studies found that the emission of oxides of nitrogen have increased significantly in Nepal in the last decade, and is second only to carbon monoxide (CO).

Another paper in 2017 by a Yale research group led by Anobha Gurung observed high levels of NO2 with an annual average 22.1 ppb (parts per billion) in 2014. By comparison, it was only 10.7 ppb in a highly polluted city like Ulaanbaatar.

Atmospheric scientist-turned-politician Arnico Panday, however, says the data for NO2 for the last 20 years are not based on surface measurements, and extrapolate  satellite data which could make them less accurate.

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“While they do show an increasing trend, the reported levels are far below levels that have health impacts,” Panday told Nepali Times.

“That said, NO2, along with its sibling nitric oxide does play a significant role in the chemistry of ozone, a gas that impacts lungs and leaves, and that has increased in Nepal, especially during the spring months.”

Vehicular pollution has long been identified as one of the major sources of air pollution in Kathmandu. But while diesel buses and trucks emit CO2, carbon monoxide and tiny soot particles, the contribution of two-wheelers has been overlooked.

Motorcycles and scooters are considered less polluting because their petrol internal-combustion engines are very efficient in converting fuel to energy. However, their exhausts give off harmful pollutants like hydrocarbons and nitrogen oxides. This is not a problem if there are only a few two-wheelers around, but the number of motorcycles and scooters in Kathmandu Valley now exceeds 1.2 million.

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“Two-wheelers, in general, emit PM2.5, black carbon, nitrogen oxides, and volatile organic compounds. Two-wheelers with older, two-stroke engines can be an important source of air pollution,” explains Pant. Motorcycles also emit other harmful gases including carbon monoxide (CO) and convert atmospheric oxygen into toxic ozone (O3).

Siva Praveen Puppala, an aerosol scientist at the International Centre for Integrated Mountain Development (ICIMOD) says motorcyclists alone cannot be blamed if other forms of public transport are not reliable. He says, “Unless we come up with cleaner alternatives for them, like an efficient mass transit, we are also at fault.”

These poisonous gases and suspended particulates together have increased the prevalence of respiratory ailments among Nepalis. A study published in the medical journal BMJ this week revealed that in 2019 Nepal recorded the highest age-adjusted death rate due to chronic lung diseases in the world at 182.5 per 100,000 population.

Over 3,000 years were lost to ill health or disability from the condition, with nearly all cases of Chronic Obstructive Pulmonary Disease (COPD) being environmental in origin, according to lead author Jay Kaufman of the Department of Epidemiology, Biostatistics and Occupational Health at McGill University in Montréal.

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The Nepal Burden of Disease 2019 report by the Nepal Health Research Council also shows that chronic respiratory diseases are the biggest killers in the country, making up over 20% of all deaths, behind only cardiovascular ailments.

“We have enough evidence to prove that air pollution is leading to a sharp increase in respiratory ailments and yet not much has been done to control this major risk factor,” says Raju Pangeni, a pulmonary specialist at HAMS hospital in Kathmandu.

“Perhaps because its impact is not easily visible much like that of the climate crisis, we are paralysed into inaction. But the burden of outdoor air pollution is so high that an individual alone can’t do much, we need politicians and bureaucrats to intervene for an actual change,” Pangeni adds.

According to the Air Quality Life Index, an initiative of the Energy Policy Institute at the University of Chicago, Nepal is the third most polluted country in the world with all of its 30 million population living in areas where the average particulate matter concentration exceeds the WHO threshold of 5μg/m³.

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‘Measured in terms of life expectancy, particulate pollution is the greatest threat to human health in Nepal, reducing life expectancy by 4.1 years on average,” the report says. ‘Child and maternal malnutrition reduce average life expectancy by about 1.3 years, while smoking reduces life expectancy by about 2.5 years on average. In Kathmandu, residents are on track to lose 3 years on average.’

Safety measures against Covid-19 such as masking up and avoiding crowded spaces are also effective in preventing a majority of respiratory diseases. There is also an increased level of awareness following the pandemic about the timely diagnosis which has made treatment manageable.

Lesser known risk factors like the burning of incense sticks or being around funeral pyres, which can equal to smoking 100 cigarettes a day, should also be communicated. Experts say that the most dangerous pollutant in Nepal are suspended particles smaller than 2.5 microns that are given off indoors from fireplaces, vehicles, brick kilns and open garbage burning. All these interventions need political will and an implementation strategy.

Read also: Polluted politics, Editorial

Kathmandu’s deadly air pollution should not just be seen as an environmental hazard, but an indication of political failure. Which is why it is encouraging that Nepal’s foremost atmospheric scientist, Arnico Panday is standing for federal elections in November from Lalitpur-3.

He has made the reduction of air pollution his highest priority along with climate adaptation, transport safety, heritage conservation, domestic job creation, and access to high quality education and healthcare.

Said Panday: “If elected, in the first year I plan to empower and incentivise local governments to crack down on polluters within their jurisdictions, create an entity to fight forest fires from the ground and the air, and introduce a comprehensive clean air act that will bring Nepal’s air quality within WHO guidelines by 2030.”

Read also: How to clean up Kathmandu’s air, Anil Chitrakar

Sonia Awale


Sonia Awale is Executive Editor of Nepali Times where she also serves as the health, science and environment correspondent. She has extensively covered the climate crisis, disaster preparedness, development and public health -- looking at their political and economic interlinkages. Sonia is a graduate of public health, and has a master’s degree in journalism from the University of Hong Kong.

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