Air pollution: A public health problem

Air Pollution - non-communicable disease - air quality
File: Kathmandu’s AQI, as of 8am, on Monday, January 4, 2021, was at 487. Photo: Aryan Dhimal/Onlinekhabar

Air pollution has emerged as a significant public health concern globally in recent decades. Air pollution is defined as the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. Pollutants of air pollution mainly include particulate matter (PM), carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide.

Among the air pollutants, Particulate Matter (PM) is the most dangerous form of pollutant. Particulate matter is the complex mixture of solids and aerosols composed of small droplets of liquid, dry solid fragments. Particulate matter can contain inorganic ions, metallic compounds, elemental carbon, and organic compounds, and vary in size, shape, and chemical makeup. PM with a diameter of 10 microns is classified as PM 10 and with 2.5 microns or less in diameter as PM 2.5. The size of PM 2.5 is just three per cent the diameter of a human hair and it is more dangerous to human health in contrast to PM 10.

The combustion of fuels such as gasoline, oil, diesel, and wood is a major source of PM 2.5 pollution, along with activities like construction, agriculture, wildfires, and industrial processes. Despite efforts to mitigate air pollution, many regions fail to meet the World Health Organization’s (WHO) air quality guidelines.

In 2021, in response to an increase in the quality and quantity of evidence of air pollution impacts, the WHO updated the PM 2.5 annual mean air quality guideline to 5µg/m³, which represents clean air as few impacts have been observed below these levels. In 2019, 99% of the world population was living in places where the WHO’s strictest 2021 air quality guideline levels were not met.

Each day, as we inhale air, an invisible storm of particles and molecules infiltrates our bodies that can pose a threat to our lungs, hearts, and brains, and cause a host of other health problems. Air pollution is a global problem, it disproportionately affects those living in developing nations and particularly the most vulnerable, such as women, children, and the elderly. Air pollution increases the morbidity and mortality from non-communicable cardiovascular disease and respiratory diseases. Air pollution is a major contributing factor for seven of the top 10 leading causes of death globally, namely: chronic obstructive pulmonary disease (COPD), ischemic heart disease, lower respiratory infections, stroke, lung cancer, diabetes, and neonatal deaths.

The burden of disease associated with both ambient and indoor air pollution exposure is large and growing. There are an estimated 7 million premature deaths worldwide each year due to air pollution, making it the biggest environmental threat to public health. According to WHO, Air pollution kills 13 people every minute globally due to lung cancer, heart disease, and strokes.

Air pollution in Nepal

In 2023, the average PM 2.5 concentration in Nepal was 8.5 times higher than the WHO annual air quality guideline value making it the 8th most polluted country in the world.

In Nepal, sources of air pollution include both natural and anthropological sources like forest fires, vehicular emissions, combustion of coal, firewood, and fossil fuel, pesticide spraying, agricultural harvesting, emissions from construction sites, industries, etc. As it is the cheapest form of energy, fossil fuel combustion has been one of the most contributing factors to air pollution.

Weather variations have a strong correlation with pollution levels in Nepal. Air pollution levels start to rise just after the end of the monsoon. Generally, the air quality in Nepal starts deteriorating in late October. The winters are the worst-hit season in terms of air pollution with peaks in pollution levels occurring in December through to January. Major cities of Nepal such as Kathmandu, Bhaktapur, Patan, etc. rank among the top most polluted cities across the world during this period.

Health effects due to air pollution

Healthcare system
Photo by National Cancer Institute on Unsplash

In Nepal, air pollution leads to 42,100 deaths every year, out of which 19 per cent are in under-five children and about 27 per cent in adults above 70 years of age. The data on the major causes of death in Nepal also shows that air pollution is a major contributor to the top five causes of death, namely COPD (66 per cent), ischemic heart disease (34 per cent), stroke (37 per cent), Lower respiratory infection (47 per cent) and neonatal deaths (22 per cent)

Measured in terms of life expectancy, particulate matter pollution is the greatest threat to human health in Nepal, reducing life expectancy by 4.1 years on average. In contrast, child and maternal malnutrition reduces average life expectancy by about 1.3 years, while smoking reduces life expectancy by about 2.5 years on average. According to the Nepal Burden of Disease 2019 survey, air pollution ranked in the top five leading risk factors for deaths.

Air pollution monitoring in Nepal

Currently, there are 27 Air Quality Monitoring Stations (AQMSs) across the nation run by the Ministry of Forests and Environment, Government of Nepal. These AQMSs measure PM (PM10, PM2.5, PM1), Black carbon concentration, Ozone(O3) concentration (Surface Ozone), Carbon monoxide (CO) concentration, Sulphur dioxide (SO2) concentration, NOx, NO, NO2 concentration, Meteorology parameters (Temperature, humidity, pressure, rainfall, wind).

How to protect yourself from air pollution

Here’s a list of things you can do to protect yourself from the effects of air pollution:

  • Use masks while travelling outdoors: Face masks prevent the entry of PM  into our bodies.
  • Stop burning refuses Waste burning releases a lot of particulate matter and black carbon, which is harmful to our health. Burning of plastics releases chemical carcinogens.
  • Use electrical stoves: Recent studies have shown that even gas stoves release harmful gases such as nitrogen dioxide and formaldehyde.
  • Prioritise public transportation: By using public transport, we contribute to decreasing the number of vehicles on the road, which leads to a reduction in vehicular emissions.
  • Stop smoking: Smoke from cigarettes releases particulate matter that not only the smoker but also the people around them.

Prevention and control

The constitution of Nepal 2072 has mentioned that it’s the fundamental right of all individual to live in clean and healthy environment. According to the National Environment Policy, 2076 BS, national standards will be developed and put into effect to prevent pollution in the areas of water, air, soil, sound, electricity, magnetic waves, radioactive radiation, and dangerous chemicals. The transport sector is one of the most significant drivers of air pollution. Nepal’s existing Finance Act includes a pollution control fee of 1.50 Nepali rupees (NPR) per litre on petrol or diesel sold within the country.

Policy implementation, environment-friendly and sustainable infrastructure development, ventilated housing system, use of electric vehicles, increased use of electric energy, solar power generation in place of fossil fuel, waste management, advancement in monitoring and technological systems, research and education regarding air pollution, etc. can be the methods to prevent and control air pollution. The agriculture sector, infrastructure and development sector, health sector, environment sector, etc must coordinate to prevent and control the current issue of air pollution. 

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Rana is a student of Public Health at Tribhuvan University.

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