Sharad Shrestha

Air pollution may be defined as the presence of one or more contaminants such as dust, fumes, gas, mist, odour, smoke or vapour in the atmosphere which may prove to be injurious to plant, animals and human life.
It is also defined as the outdoor ambient atmosphere containing harmful pollutants which adversely affect man and his environment. To a large extent, man himself is responsible for air pollution. His activities, careless technology, casual attitude and lack of awareness may contribute to air pollution.

Polluted City
Sometimes natural factors such as fog, mist, bacteria, wind velocity and its direction and volcanic ash may be the cause of air pollution. Moreover large increases in population causing loss of forest and advancement of modern technology have resulted in air pollution problem in recent years. The air at the surface consists primarily of nitrogen and oxygen 78 and 21 percent respectively. Much of the remaining one percent is water vapour and carbon dioxide.
Kathmandu is regarded as one of the most polluted cities in Asia. It is high time to give due attention upon the mitigation of the pollution in this capital city of Nepal. The Bagmati River running through Kathmandu is no more than an open sewer.
The air quality is so toxic that it causes major health problems. Residential and industrial garbage is not handled effectively. According to Yale’s 2014 “Environmental Performance Index” (EPI), Nepal’s air quality ranks 177th out of 178, better than only Bangladesh. According to Department of Environment (DOE) in 2017, 24-hour average of Total Suspended Particles (TSP) in a site in Kathmandu was 4,749microgram/m3, average PM10 was 2,928 microgram/m3 and PM2.5 was 226 microgram/m3.
Out of 122 nations, Kathmandu is the seventh polluted capital of the world in terms of pollution. PM2.5 is a small, airborne particulate matter (2.5 microns and less). These are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated.
Vehicular exhaust and re-suspended road dust from unpaved and poorly maintained roads are the major sources of air pollution in Kathmandu Valley. Unprecedented Growth of motor vehicles and ongoing road expansion activity has led to further degradation in the air quality of the valley. Air pollution level in Kathmandu is good and Air Quality Index (AQI) is 31 US where as pollutants namely PM2.5, PM10 and Ozone O3 and their Concentrations are 6.4 microgram/m3, 34.5 microgram/m3 and 52 microgram/m3 respectively.
The Global COVID-19 pandemic has had forced the public indoors and pushed general life to a halt around major cities of the world for several weeks. Nepal had also been under a lockdown since March 24, 2020 for several weeks with restricted public and transport movement across the country. With brick kilns and factories shut and a massive reduction in traffic on roads due to lockdown improvement, air quality in Kathmandu City has seen a significant improvement. Due to this lockdown, the average concentration of PM2.5 (pollutants that have a dia. of less than 2.5 micrometer) decreased by 34.9 micrograms per cubic meter in Kathmandu, as per the findings of the researchers’ study on air quality data from January1 to April 24.
Nearly a week after the government imposed a temporary lockdown across the nation to contain the spread of the corona virus (COVID-19), the Kathmandu Valley and other major cities have started to witness a significant improvement in their Air Quality Index (AQI). As the movement of people and vehicles had been stopped and industries were not allowed to operate, it is evident that air quality has been improved in Kathmandu.
A study had been conducted on 40 major cities of the world from all the six continents. It indicated that air pollution levels have been significantly declined in cities under lockdown.

Major Pollutants
As part of study, researchers measured six major pollutants including PM2.5 and PM10, to record how air quality improved under lockdown and travel restrictions. The study found that PM2.5 concentration saw a significant decline in 17 cities in February 2020 compared to February 2019 and 14 cities witnessed declines in March 2020 compared to the same month in last year.
As per Global Institute of Interdisciplinary Studies, a think tank based in Kathmandu, air quality has still been found improved in Kathmandu like wind and humidity. PM2.5 and PM 10 have been decreased from 135.4 to 108.3 microgram/m3 and 54.6 to 42.2 micro gram/m3respectively in Kathmandu before and after the lockdown was enforced. But even after the improvements, air quality in Kathmandu is still not suitable for certain groups such as senior citizens and people with respiratory ailments.
The WHO’s air quality guidelines stipulate that 24 hour mean PM2.5 should not exceed 25 microgram/m3 and that for PM10 should not exceed 50microgram/m3.
As per health recommendations, windows need to be opened to bring clean, fresh air indoors and enjoy outdoor activities in order to protect us from air pollution in Kathmandu. Also need to use air pollution mask and home air purifier in order to best protect from the same. Concerned authorities who imposed stringent measures for containing COVID-19 should treat air pollution with similar urgency as air pollution is also a leading global health issue in the present scenario.
Rapid progress in industrialization and mechanization has resulted in unlimited exploitation of natural resources. Thus, air pollution is a gift of industrial civilization. The main sources of air pollution in Kathmandu are industries and vehicles. Other minor sources are domestic cooking fuels, refuse burning and resuspended dust particles. World Health Organization (WHO) estimates that approximately 3 million people die each year due to air pollution in the world. According to the WHO, air pollution is responsible for increases in outpatient visits due to respiratory and cardiovascular diseases, hospital admissions and mortality. The most common route for pollutants to enter the human body is by inhalation. So the most common effect of air pollution is development of respiratory diseases.

Role of EVs
Ministry of Population and Environment has also established air quality monitoring systems in Kathmandu valley. These monitoring stations automatically collect 24-hour samples of air and the samples are analysed for PM10. Electric vehicles (EVs) can play an important role in reducing emission loads in Kathmandu.
The government should introduce economic tools, such as fuel tax, to discourage the use of diesel vehicles. Public awareness campaigns are required to inform the people about the hazards of air pollution and the impact of COVID – 19 due to lockdown and its impact after lockdown. Joint efforts in terms of mutual cooperation, coordination and cooperation are quite needed to mitigate air pollution. Also, implementation of effective policies, plans and programs (PPP) at national and international levels is a must in this regard.

(Shrestha regularly writes on environment issues)