Toxic Air: How Air Pollution Is Damaging Our Health

South Asia faces one of the most severe air pollution crisis in the world. According to the report of State of Global air, about 7.9 million deaths were attributed to exposure to air pollution worldwide. Early exposure to air pollutants leads to lifelong vulnerability to respiratory diseases. Today 9 out of 10 People are breathing air that is above the recommended level of WHO guidelines. Air pollution is not only responsible for respiratory diseases but also major contributor for stroke, cardiovascular diseases, asthma.

Air pollution occurs when harmful substances/chemicals present in the atmosphere in quantities and duration high enough above normal ambient levels to produce a measurable effect (harmful) on human, health, animals and the environment. Air pollutantscan come from many sources: Transportation, Electric Power generation, trash burning, Industrial Processes. The air pollutant are mainly of two types

– Primary air pollutants: Emitted directly into the air from natural or human activities. These include particulate matter (PM), carbon monoxide, nitrogen oxides, sulfur dioxide, and volatile organic compounds (VOCs).

– Secondary pollutants – formed by interaction of primary pollutants with each other or with normal components of the air like Ozone, Acid Rain

Criteria Air pollutants are regulated under the National Ambient Air quality Standards (NAAQS).

– Particulate matter (PM)

– Ground level ozone

– Carbon monoxide

– Sulfur dioxide

– Lead

– Nitrogen dioxide (No2)

Health Effects to air pollution

Fine particulates matter (PM2.5), ozone, and nitrogen dioxide (NO2) are the three main indicators used to quantify air pollution.

The common pollutants is Particulate matter (PM), which consists of tiny solid particles and liquid droplets suspended in air having less than 2.5 microns and 10 microns. This smaller fine dust particles, the deeper they can penetrate into the human body and the longer they remain there. This air pollutant is one of the most significant health problems. These fine particles are emitted directly from sources like combustion in motor vechicles, power plants, mining and logging. The exposure of pollutants causes irritation of the eyes, coughing, irregular heartbeat, asthma and premature deaths. When the pregnant women is exposed to high level of pollution might be low birth weight, premature birth and fetal development issues. Normally in the Kathmandu valley in Decemeber 19, 2025 Air Quality Index rise to 130 which is very unhealthy and the Pollutant PM 2.5 level in 47µg/m3.

According to the recent report of World Bank in the topic https://www.worldbank.org/en/region/sar/publication/a-breath-of-change-solutions-for-cleaner-air-in-the-indo-gangetic-plains-and-himalayan-foothills“A Breath of Change: Solution for Cleaner Air in the Indo-Gangetic Plains and Himalayan Foothill” highlighted the PM 2.5 records more than twenty times higher than WHO level. Air pollution has reducing the lifeexpectancy by 3-5 years and causes GDP losses of 5 to 10%.Scientist have conducted thousands of studies for how air pollution can have harmful effects on human health throughout the life span. In Nepal 93% of students in primary and secondary school are at hazardous risk of PM 2.5 concentration of >35mg/m3 which is in very high level of air pollutions.

The governments in the Indo-Gangetic Plain and Himalayan Foothills, including Nepal has targeted of reducing average fine particulate matter (PM 2.5) concentrations below 35 micrograms per cubic meter by 2035 by reducing emission at the source, protecting vulnerable populations and strengthening the institutions and financing needed to sustain progress.

Rising Ozone level

Secondary pollutants, particularly Ground level ozone created through photochemical reactions under Sunlight with nitrogen oxides(NOx), and the vast amounts of uncontrolled Volatile Organic Compunds( VOCs). The main causes are Traffic Congestion or vechicular emissions. The study published in State Of Global Air 2025 https://tinyurl.com/4enbywce shows that Qatar(67.6ppb) had the highest exposure to ozone pollution with Nepal (67.5ppb), India (67.5 ppb), India (67.2 ppb), Bangladesh (65.4 ppb) and Bahrain (64.3 ppb) making up the remaining top five countries with the highest exposure. These levels current WHO air quality guidelines for ozone is set at 60mg/m3 for an 8 hour average concentration during the peak season; for region of the world where ozone level remains high. Ground level or tropospheric ozone is a pollutant that harms human health, damages plants and contributes to climate change. Although ozone is concentrated around urban areas and can travel to long distance.