Globally, some of the highest PM2.5 exposures are experienced across South Asia, although levels are  beginning to stabilise in most countries.

Air pollution leading risk factor for death in South Asia, killed 2.6 million in 2021: Report

In South Asia, air pollution has become the leading risk factor for death in terms of total population and the second leading risk factor for deaths in children under five years old, says the report

Air pollution is having an increasing impact on human health, becoming the leading risk factor for death in the South Asian region, according to the State of Global Air (SoGA) report 2024.

The report found that in 2021, air pollution accounted for 8.1 million deaths globally, including more than 7,00,000 children under five years old. This now makes air pollution the number two risk factor for death globally, putting it ahead of tobacco and poor diet.

Globally, some of the highest PM2.5 exposures are experienced across South Asia, although levels are  beginning to stabilise in most countries. In the region, levels of ozone have also increased in the last  decade, and in 2021, 56% of all global ozone deaths were reported in South Asia.  The region also experiences some of the largest health impacts in children under five. In 2021, India saw the highest total number of deaths in children under five worldwide. 

Globally, the report said, children under five years old are especially vulnerable, with health effects including premature birth, low birth weight, asthma and lung  diseases. In 2021, exposure to air pollution was linked to more than 2,60,600 deaths of children under five  years old, making it the second-leading risk factor for death in South Asia for this age group, after malnutrition. 

The exposure to air pollution was linked to more than 7,00,000 deaths globally. Out of this, a staggering  5,00,000 of these child deaths were linked to household air pollution due to cooking with polluting fuels such as wood, coal and dung. 

Impact of PM2.5, ozone and nitrogen oxide

Pollutants like outdoor fine particulate  matter (PM2.5), household air pollution, ozone (O3), and nitrogen dioxide (NO2) are having a significant impact on human  health around the world.

More than 90% of these global air pollution deaths— 7.8 million people— are attributed to PM2.5 air  pollution, including from ambient PM2.5 and household air pollution. These tiny particles, measuring less  than 2.5 micrometres in diameter, are so small they remain in the lungs and can enter the bloodstream,  affecting many organ systems and increasing the risks for noncommunicable diseases in adults like heart  disease, stroke, diabetes, lung cancer, and chronic obstructive pulmonary disease (COPD). 

According to  the report, PM2.5 has been found to be the most consistent and accurate predictor of poor health outcomes  around the world. 

Global map of national population-weighted annual average PM2 .5 concentrations in 2020.

The report also looked at the exposure levels and related health effects of nitrogen dioxide  (NO2), including the impact of NO2 exposures on the development of childhood asthma. Traffic exhaust is  a major source of NO2, which means densely populated urban areas often see the highest levels of NO2 exposures and health impacts.  

Levels of ozone, a secondary pollutant, and deaths due to ozone are increasing over time. In 2000, exposure to ozone was linked to 93,000 deaths while in 2021, exposure to ozone was linked to 2,72,000 deaths in India. 

Global map of age-standardised rates of death attributable to ozone in 2021. Nearly 50% of the total ozone-related deaths occurred in India

Impact of air pollution on children’s health

The report said that children are uniquely vulnerable  to air pollution and the damage from air pollution can start in the womb with health effects that can last a lifetime. For example, children inhale more air per kilogram of body weight and absorb more pollutants relative to adults while their lungs, bodies and brains are still developing.

Exposure to air pollution in young children is linked to pneumonia, responsible for 1 in 5 child deaths  globally, and asthma, the most common chronic respiratory disease in older children. The inequities linked to the impact of air pollution on child health are striking. The air pollution-linked death rate in  children under the age of five in South Asia is 164 deaths/1,00,000 compared to a global average of 108 deaths/1,00,000. 

Progress is underway

The report shared some positive news as well. Since 2000, the death rate linked to children under five has dropped by 53 %, due largely to efforts aimed at expanding access to clean energy for cooking, as  well as improvements in access to healthcare, nutrition, and better awareness about the harms associated  with exposure to household air pollution.  

Numerous nations, especially those with the worst air pollution, are at last addressing the issue head-on. Measurable improvements in public health and pollution are being achieved through air quality initiatives in regions such as Africa, Latin America, and Asia. Examples of these initiatives include the installation of air pollution monitoring networks, the implementation of stricter policies, and the switch to electric vehicles to offset traffic-related air pollution.

Even while the situation is being monitored, more needs to be done to prevent air pollution from becoming the leading cause of death for millions of people, surpassing other health hazards. 

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