As air pollution continues to affect cities worldwide, concerns are growing about its impact on human health. While the atmosphere naturally contains gases essential for survival, pollutants released by vehicles, industry, power plants, agriculture, and forest fires are increasingly degrading the air people breathe.
Explaining how the human body responds to polluted air, Dr. Vijay Mohan S highlights the remarkable protective mechanisms of the respiratory system, while cautioning that prolonged exposure to harmful pollutants can overwhelm these natural defences.
Earth’s atmosphere comprises approximately 78% nitrogen, 21% oxygen and small quantities of argon, carbon dioxide and other trace gases. Marine phytoplankton, algae and certain bacteria contribute nearly half of the planet’s oxygen production through photosynthesis.
However, the air we breathe also contains particulate matter and harmful gases, including nitrogen dioxide, sulphur dioxide, carbon monoxide and ground-level ozone. Major sources include vehicular emissions, industrial activities, fossil-fuel combustion, construction dust, agricultural practices and wildfires.
How Do Our Lungs Protect Us?
The respiratory system has several natural defence mechanisms to prevent harmful substances from entering deeper parts of the lungs. The airways produce mucus, which traps dust, microbes and other particles. Tiny hair-like structures called cilia continuously move this mucus towards the throat, where it can be coughed out or swallowed.
Immune cells, particularly macrophages, also help identify and remove foreign particles that reach the deeper airways.
However, these protective mechanisms have limitations. Fine particulate matter, especially PM2.5, can penetrate deep into the lungs and, in some cases, enter the bloodstream.
The Health Risks Of Prolonged Exposure
According to the World Health Organization (WHO), air pollution is associated with serious health conditions, including chronic obstructive pulmonary disease (COPD), respiratory infections, lung cancer, heart disease and stroke. Exposure can also affect pregnancy outcomes, while children, older adults and people with existing health conditions are particularly vulnerable.
Dr. Mohan emphasises that protecting respiratory health requires reducing exposure to polluted air and addressing pollution at its sources. Cleaner energy, better ventilation, reduced vehicular emissions and stronger environmental protection measures are essential to safeguarding public health.
