Extreme heat is no longer just a seasonal discomfort. Across many cities, rising temperatures are now worsening air pollution and smog, creating serious health risks, especially for people with asthma, Chronic Obstructive Pulmonary Disease (COPD), allergies, and other respiratory illnesses. Doctors are increasingly warning that heatwaves and polluted air together can become a dangerous "double burden" for the lungs.
Research shows that high temperatures can worsen air pollution, increase ground-level ozone, trap harmful particles in the air, and trigger breathing emergencies. People with existing lung diseases are among the most vulnerable.
During heatwaves, the atmosphere often becomes stagnant. Hot air gets closer and closer to the ground, preventing pollutants from dispersing properly. As a result, harmful pollutants such as PM2.5, PM10, nitrogen dioxide, and ozone begin to accumulate in the air.
High temperatures also accelerate chemical reactions between pollutants released from vehicle exhaust, industries, and smoke, increasing the formation of ground-level ozone - one of the major components of smog. This pollutant is highly irritating to the airways and lungs.
In many urban areas, concrete buildings, traffic congestion, lack of greenery, and the "urban heat island effect" further worsen the situation by trapping heat and pollutants for longer durations.
Breathing already becomes harder during very hot weather because the body uses extra energy to cool itself. When polluted air is added to the mix, the respiratory system comes under even greater stress.
Hot and polluted air can:
For people with asthma or COPD, these changes can quickly lead to flare-ups, breathing difficulty, or even hospitalisation. Studies have shown that hospital admissions and respiratory deaths increase during periods of high heat combined with poor air quality.
People with asthma often experience worsening symptoms during heatwaves because heat and smog directly irritate sensitive airways.
Common triggers during extreme heat include:
Children are particularly vulnerable because their lungs are still developing and they breathe faster than adults, increasing exposure to pollutants.
COPD patients are among the highest-risk groups during heatwaves. Their lungs are already damaged and less efficient at handling environmental stress.
When temperatures rise:
Research suggests that COPD hospitalisation and mortality rates rise during prolonged heat exposure. Heatwaves can also worsen dehydration, which thickens mucus inside the lungs, making breathing even more difficult.
One important concern is that the effects of heatwaves and smog are not always immediate. Respiratory symptoms may continue even several days after temperatures return to normal.
People may experience:
This delayed impact often causes people to underestimate the health risks associated with heat exposure and poor air quality.
Immediate medical attention may be needed if a person develops:
Certain groups are more vulnerable during heatwaves and smog episodes:
People who already have reduced lung function may struggle even with short exposure to extreme heat and polluted air.
Simple precautions can significantly reduce the risk of respiratory complications.
Doctors and researchers believe that climate change will continue increasing the frequency of heatwaves, poor air quality episodes, and respiratory illnesses globally.
This is becoming a growing public health concern, especially in densely populated urban regions where pollution levels are already high.
Experts emphasise that protecting respiratory health now requires not only medical management but also environmental awareness, cleaner air policies, urban greenery, and public education.
Heatwaves and smog are no longer separate environmental problems. Together, they create a serious threat to lung health, particularly for people living with asthma, COPD, and other respiratory diseases.
The combination of extreme heat, stagnant air, and pollution can silently strain the lungs, worsen breathlessness, and increase emergency respiratory conditions. Recognising early symptoms, taking preventive steps, staying hydrated, and reducing exposure to polluted outdoor air can help protect vulnerable individuals during extreme weather conditions.
As heatwaves become more frequent, awareness and timely precautions may play a major role in preventing respiratory emergencies and protecting long-term lung health.
(By Dr. Pranay Sai Chandragiri, Consultant Interventional Pulmonologist, Yashoda Hospitals, Hyderabad)
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