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Air pollution: a public health problem

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

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

Among air pollutants, particulate matter (PM) is the most dangerous form of pollutant. Particulate matter is the complex mixture of solids and aerosols consisting 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 composition. PM with a diameter of 10 microns is classified as PM 10 and with a diameter of 2.5 microns or less as PM 2.5. The size of PM 2.5 is only three percent of the diameter of a human hair and is more dangerous to human health than 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 such as construction, agriculture, forest fires and industrial processes. Despite efforts to reduce air pollution, many regions do not meet World Health Organization (WHO) air quality guidelines.

In 2021, in response to an increase in the quality and quantity of evidence of air pollution impacts, WHO updated the PM 2.5 guideline for annual average air quality to 5 µg/m³, which represents clean air, as few impacts below these levels have been observed. In 2019, 99% of the world’s population lived in places that did not meet the WHO’s strictest air quality guidelines for 2021.

Every day, as we breathe air, an invisible storm of particles and molecules infiltrates our bodies that can threaten our lungs, heart and brain, and cause a host of other health problems. Air pollution is a global problem and disproportionately affects people in developing countries, especially the most vulnerable, such as women, children and the elderly. Air pollution increases morbidity and mortality due to non-communicable cardiovascular and respiratory diseases. Air pollution is a major factor contributing to seven of the ten leading causes of death worldwide, 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 exposure to indoor and outdoor air pollution is high and growing. Globally, there are an estimated seven million premature deaths each year from air pollution, making it the greatest environmental threat to public health. According to the WHO, air pollution kills 13 people worldwide every minute due to lung cancer, heart disease and stroke.

Air pollution in Nepal

In 2023, Nepal’s average PM2.5 concentration was 8.5 times higher than the WHO’s annual air quality guideline, making the country the 8th most polluted country in the world.

In Nepal, sources of air pollution include both natural and anthropological sources such as forest fires, vehicle emissions, burning of coal, firewood and fossil fuels, spraying of pesticides, agricultural harvests, emissions from construction sites, industries, etc. As it is the cheapest form of energy the combustion of fossil fuels is one of the factors that contribute most to air pollution.

Weather variations have a strong correlation with pollution levels in Nepal. Air pollution levels start to rise soon after the end of the monsoon. In general, air quality in Nepal starts to deteriorate in late October. Winters are the worst affected season in terms of air pollution, with peaks in pollution levels from December to January. Major cities of Nepal such as Kathmandu, Bhaktapur, Patan, etc. are among the most polluted cities in the world during this period.

Health effects due to air pollution

Healthcare system
Photo by the National Cancer Institute on Unsplash

In Nepal, air pollution causes 42,100 deaths annually, of which 19 percent occur in children under the age of five and about 27 percent in adults over the age of 70. The data on the leading causes of death in Nepal also shows that air pollution is a major contributor to the top five causes of death, namely COPD (66 percent), Ischemic heart disease (34 percent), Stroke (37 percent), Lower respiratory infections (47 percent) and neonatal deaths (22 percent)

Measured in terms of life expectancy, particulate matter pollution is the greatest threat to human health in Nepal, reducing life expectancy by an average of 4.1 years. In contrast, malnutrition in children and mothers 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 is among the top five leading risk factors for deaths.

Air pollution monitoring in Nepal

Currently, there are 27 Air Quality Monitoring Stations (AQMSs) across the country, run by the Ministry of Forests and Environment of the Government of Nepal. These AQMSs measure PM (PM10, PM2.5, PM1), black carbon concentration, ozone (O3) concentration (surface ozone), carbon monoxide (CO) concentration, sulfur dioxide (SO2) concentration, NOx, NO, NO2 concentration, meteorology parameters (temperature, humidity, pressure, rainfall, wind).

How to protect yourself from air pollution

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

  • Use masks when traveling outdoors: Face masks prevent PM from entering our body.
  • Stop burning waste The incineration of waste releases a lot of particulate matter and black carbon, which is harmful to our health. When plastic is burned, chemical carcinogens are released.
  • Use electric heaters: Recent studies have shown that even gas stoves release harmful gases such as nitrogen dioxide and formaldehyde.
  • Prioritize public transport: By using public transport we contribute to reducing the number of vehicles on the road, which leads to a reduction in vehicle emissions.
  • Stop smoking: Cigarette smoke releases particles that occur not only in the smoker but also in the people around them.

Prevention and control

The Constitution of Nepal 2072 states that it is the fundamental right of every individual to live in a clean and healthy environment. According to the National Environmental Policy, 2076 BS, national standards will be developed and implemented to prevent pollution in water, air, soil, noise, electricity, magnetic waves, radioactive radiation and hazardous chemicals. The transport sector is one of the main causes of air pollution. The existing Nepalese financing law includes a pollution control levy of 1.50 Nepalese Rupees (NPR) per liter on petrol or diesel sold in the country.

Policy implementation, environmentally friendly and sustainable infrastructure development, ventilated housing system, use of electric vehicles, increased use of electric energy, solar energy generation instead of fossil fuels, waste management, advances in monitoring and technological systems, research and education related to 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 work together to prevent and control the current problem of air pollution.