Air Pollution's Deadly Grip On Southern And Eastern Asia

Air pollution is a pressing issue in Southern and Eastern Asia, with countries in these regions recording some of the worst air quality in the world. In 2023, Bangladesh, Pakistan, and India were ranked among the countries with the worst air quality, with Nepal and Sri Lanka also facing significant pollution challenges. The sources of this pollution include industrial emissions, agricultural waste burning, cremation practices, the burning of solid fuels, plastic rubbish incineration, and vehicle emissions. The impacts of air pollution are devastating, with millions of premature deaths each year attributed to poor air quality in the region. The World Health Organization (WHO) reports that globally, 4.2 million people die annually from heart disease, stroke, lung cancer, and acute/chronic respiratory diseases linked to air pollution. The dangers of air pollution are particularly acute in low- and middle-income countries in Southeast Asia, where 91% of premature deaths due to air pollution occur. The impacts of air pollution are worsened by a hotter climate, and the same pollutants that harm air quality also contribute to climate change, creating a vicious cycle.

The geography of South Asia traps pollutants in the region

South Asia is home to nine of the world's ten cities with the worst air pollution. The region's unique geography plays a significant role in the accumulation of air pollution. The Indo-Gangetic Plain, which includes Bangladesh, eastern Pakistan, most of northern and eastern India, and southern Nepal, is a vast plain where pollutants from various sources converge. These pollutants are then trapped by the Himalayas to the north, creating a thick layer of smog that affects the entire region.

The geography of South Asia, with its large river basins and mountain ranges, influences the movement and concentration of pollutants. The Indo-Gangetic Plain, for instance, is a vast, flat expanse of land that allows pollutants to spread easily. The Himalayas, the world's tallest mountain range, act as a barrier, trapping pollutants and preventing their dispersal. This geographical setup, combined with the region's climatological conditions, creates large "airsheds" where pollutants accumulate and affect vast areas.

During the winter, stable atmospheric conditions with dry and denser cold air trap pollutants close to the surface. The cold temperatures also increase the burning of solid fuels for heating and cooking, adding to the pollution levels. This combination of geographical and climatological factors results in prolonged episodes of poor air quality, often requiring school closures, transport limitations, and agricultural burning bans to protect the population.

The impact of this trapped pollution is devastating. Fine particulate matter (PM2.5), one of the most damaging types of air pollution in the region, poses significant health risks. These microscopic particles, released from the burning of fossil fuels, biomass, and agricultural waste, can penetrate deep into the lungs and enter the bloodstream, triggering heart disease, lung cancer, and other fatal diseases. The health effects of air pollution in South Asia range from respiratory infections to chronic diseases, serious discomfort, and premature mortality.

The pollutants trapped in South Asia are not only harmful to human health but also contribute to climate change. Substances like methane and black carbon, a form of PM2.5, trap the sun's heat, accelerating global warming. The worsening air pollution in South Asia, driven by industrialization, economic development, and population growth, has made it a global hotspot for poor air quality. The region's unique geographical features play a crucial role in trapping and concentrating these pollutants, affecting the lives and health of millions.

Fine particulate matter is dangerous to human health

Fine particulate matter, or PM2.5, is a dangerous component of air pollution in Southern and Eastern Asia. These particles are 2.5 microns or smaller in diameter—a fraction of the width of a human hair. Their tiny size allows them to penetrate deep into the lungs and enter the bloodstream, causing a range of serious health issues.

PM2.5 is released during natural events such as dust storms and wildfires, as well as human activities like coal burning, agricultural waste burning, cremation practices, and vehicle emissions. In Southern Asia, the geography of the region also plays a role. Pollutants from the Indo-Gangetic Plain, which includes Bangladesh, eastern Pakistan, northern and eastern India, and southern Nepal, mix and become trapped by the Himalayas.

The health impacts of fine particulate matter are significant. Long-term exposure to PM2.5 has been linked to premature death, particularly in individuals with chronic heart or lung diseases. It is also associated with reduced lung function growth in children and an increased risk of lung cancer. The International Agency for Research on Cancer (IARC) has concluded that particulate matter in outdoor air pollution causes lung cancer.

In addition to the direct health effects, fine particulate matter also affects visibility and ecosystems. It reduces visibility by altering how light is absorbed and scattered in the atmosphere. Deposition of PM2.5 on plants, soil, and water can impact plant growth and yield, as well as water quality.

The dangerous levels of fine particulate matter in Southern and Eastern Asia have led to emergency declarations and the closure of public places, schools, and construction sites in some areas. To improve air quality and protect public health, governments in the region have been advised to invest in renewable energy initiatives, promote cleaner vehicles, improve infrastructure for better pedestrian mobility, and ban certain agricultural burning practices.

Ground-level ozone is a common pollutant that causes respiratory issues

South and East Asian countries, including Bangladesh, Pakistan, India, Nepal, China, Indonesia, Myanmar, Vietnam, and the Philippines, are facing dangerous levels of air pollution. The sources of this pollution include brick kiln and industrial emissions, agricultural waste burning, cremation practices, solid fuel burning, plastic rubbish incineration, vehicle fumes, and forest fires.

Ozone aggressively attacks lung tissue, causing inflammation and damaging the airway lining. This can lead to a range of respiratory issues, including asthma, emphysema, and chronic bronchitis. Even relatively low levels of ozone can have harmful health effects, and the risk of adverse effects increases with exposure time. Long-term exposure to ground-level ozone has been linked to an increased risk of respiratory illnesses, metabolic disorders, nervous system issues, and reproductive problems.

Ground-level ozone can also have ecological impacts, affecting sensitive vegetation and ecosystems, including forests, parks, and wildlife refuges. It slows photosynthesis, hampering plant growth and potentially impacting entire ecosystems.

The risks associated with ground-level ozone are particularly concerning given its prevalence in urban environments, where it can reach unhealthy levels on hot sunny days. Climate change, by driving warmer temperatures, is leading to increased levels of ground-level ozone. This is a growing concern in South and East Asian countries, where air pollution is already at critical levels.

To address this issue, governments in the region have been advised to invest in renewable energy initiatives, introduce incentives for cleaner vehicles, improve infrastructure for better pedestrian mobility, and ban certain agricultural practices that contribute to air pollution.

Air pollution impacts the environment and plant growth

South and Eastern Asia have some of the worst air quality in the world. In 2023, Bangladesh recorded the poorest air quality of 134 countries monitored by IQAir, a Swiss climate group. Pakistan and India were close behind, with India occupying nine of the top ten spots for the most polluted cities. The geography of South Asia plays a role in this accumulation of air pollution. Pollutants emitted from across the Indo-Gangetic Plain, which comprises Bangladesh, a large part of eastern Pakistan, most of northern and eastern India, and the south of Nepal, mix with pollutants brought in by winds from the coast. These pollutants then become trapped by the Himalayas.

Air pollution has detrimental effects on the environment and plant growth. Firstly, it reduces the amount of sunlight that reaches the surface, impacting the rate of photosynthesis and slowing the growth of forests and crops. For example, between 1980 and 2011, nine billion dollars' worth of soybeans and corn were lost in the US due to ozone pollution. Furthermore, air pollutants can be deposited onto plants through direct contact, known as "dry deposition," or through precipitation, called "wet deposition." These pollutants can include reactive nitrogen compounds such as ammonia and nitrogen oxides, which are toxic to sensitive plants and trees and can alter the chemical nature of the soil, robbing plants of the nutrients necessary for growth. Gaseous ammonia from agriculture and nitrogen dioxide from vehicle emissions increase nitrogen levels in the soil, which can limit the growth of certain plant species and disrupt the balance of ecosystems. Additionally, sulphur dioxide, produced from burning fuels, particularly coal, has harmful effects on vegetation.

The impacts of air pollution on the environment and plant growth are interconnected and far-reaching. As air pollution contributes to climate change, ecosystems are changing faster than plants and animals can adapt, leading to species extinction. Water bodies such as rivers and lakes are also susceptible to the effects of air pollution, with marine ecosystems vulnerable to ocean acidification caused by carbon dioxide dissolution in seawater.

Climate change and air quality are linked

Air pollution is a pressing issue in Southern and Eastern Asia, with countries in the region topping global rankings for poor air quality. In 2023, Bangladesh, Pakistan, and India were reported to have the worst air quality in the world. The same year, 96% of air quality monitoring stations in Lahore and Peshawar in Pakistan, as well as Dhaka in Bangladesh, were not affiliated with their respective governments.

The climate crisis and air quality are inextricably linked. Firstly, climate change negatively impacts air quality. Atmospheric warming associated with climate change increases ground-level ozone, which is a major component of smog and contributes to respiratory issues. Warmer temperatures also lengthen the pollen season and increase pollen production, leading to higher concentrations of airborne allergens that degrade air quality and trigger respiratory problems. Furthermore, extreme weather events caused by climate change, such as heatwaves and droughts, can further deteriorate air quality. Heatwaves create stagnant air that concentrates air pollutants, and droughts increase the likelihood of forest fires, which release harmful substances into the atmosphere.

Secondly, air pollution exacerbates climate change. Certain air pollutants, such as methane and black carbon, are greenhouse gases that trap heat in the Earth's atmosphere, accelerating global warming. While these pollutants have a shorter lifespan than other greenhouse gases, they cause significantly more warming per unit of mass. Additionally, air pollutants increase the amount of aerosols in the atmosphere, leading to the formation of more clouds that trap heat and contribute to warming.

The link between climate change and air quality underscores the urgency of addressing both issues simultaneously. By reducing air pollution, countries in Southern and Eastern Asia can improve public health and human rights while also mitigating the impacts of climate change. This includes implementing renewable energy initiatives, improving vehicle emission standards, and fostering the transition to electric cars.

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