Delhi Is World's Most Polluted Capital—But How Deep Does PM2.5 Penetrate Human Body?

Switzerland Air Quality Index (AQI) recently released a list of the world's most polluted cities, revealing that six out of the top 10 were in India. New Delhi was listed as the most polluted capital city globally, followed by N'Djamena—the capital of Chad, a country in Central Africa known for having the world's worst air pollution. The 2024 World Air Quality Report also stated that the US State of California houses ten of the fifteen most polluted cities in North America. Besides, Ontario and Bloomington, both in Canada, were also listed as cities with the worst air quality.

How Severe Is Air Pollution?

World Health Organisation (WHO) data show that almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries (LMIC) suffering from the highest exposures. "Ambient (outdoor) air pollution in both cities and rural areas is causing fine particulate matter which results in strokes, heart diseases, lung cancer, and acute and chronic respiratory diseases. Additionally, around 2.6 billion people are exposed to dangerous levels of household air pollution from using polluting open fires or simple stoves for cooking fuelled by kerosene, biomass (wood, animal dung and crop waste) and coal," the global health agency said in a statement.

Global Health Agencies Raise Alarm Over Air Quality

While the air pollution list sent shockwaves across the world, no statement or plan of action has been announced by any countries as of yet. However, health experts across the world have raised alarms about the health risks of breathing in polluted air. WHO released a social media post stating that air pollution is responsible for 36% of deaths from lung cancer, 34% from strokes, and 27% from heart disease. Air pollution in the form of PM2.5 can lead to strokes, diabetes, heart disease, lung cancer, and respiratory illnesses. It also affects prenatal and neonatal health, contributing to complications and deaths.

How Does PM2.5 Impact Heart?

Research has shown that particulate matter, particularly PM2.5 can spill into your bloodstream through the air that goes into your lungs, and lead to the majority of cardiovascular diseases. In some cases, where the exposure is short-term, it could lead to the risk of arrhythmias, heart attacks, and even strokes. Long-term exposure to these toxic particulate matter can lead to plaque buildup in the arteries and increase the risk of heart disease.

How Does Air Pollution Impact Brain?

Research indicates that air pollutant exposure is linked to adverse effects on brain health, including neuroinflammation, oxidative stress, and potential contributions to neurodegenerative diseases and cognitive decline. A systematic review in the journal Nature found that exposure to pollutants, particularly PM2.5, can trigger processes that cause cognitive deterioration, alterations in the blood–brain barrier, and cerebrovascular dysfunction.

PM2.5 Poses Significant Risk To Preganant Moms

Air pollution can lead to complications in birth. Babies born under conditions where their mothers are exposed to polluted air are at a higher risk for a range of health problems, both in early life and as they grow older. Moreover, pollution can interfere with fetal growth and cause inflammation, which can pass through the placental barrier and lead to respiratory problems, such as asthma, later in the child's life. The third trimester of pregnancy is particularly vulnerable to the effects of high pollution. Studies indicate that exposure to pollution during this period is associated with an increased risk of neurodevelopmental disorders, including autism and delays in brain development.

Air pollution may or may not be visible to the naked eye, but every time you breathe in it, remember there are long term implications.