Lung cancer risk: Air pollution is injurious to never-smokers' health
A new study by the International Agency for Research on Cancer found lung cancer rising among those who have never smoked a cigarette in their life. Air pollution was cited as one of the prime reasons
In India, all smoking scenes in a film are accompanied with the statutory warning as smoking causes lung cancer. However, the latest study by the International Agency for Research on Cancer, published in February in the Lancet Respiratory Medicine journal, found that lung cancer is on the rise among those who have never smoked a single cigarette in their lives. A primary cause for this? Air pollution.
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The study stated that lung cancer among non-smokers is the fifth highest cause of cancer deaths worldwide now. This finding is particularly alarming for India, where air pollution is rising unabated, and multiple Indian cities consistently feature in ‘top 10 most polluted cities in the world’ lists.
“This research has stressed that environmental factors play a huge part in elevating the risk of cancer, especially air pollution," says Dr Sumeet Singhania, consultant for pulmonary medicine, Kokilaben Dhirubhai Ambani Hospital, Mumbai. “Here comes this study that states that long-term exposure to air pollution may also cause lung cancer, even in non-smokers. The very high concentrations of pollutants like PM2.5, nitrogen dioxide, sulphur dioxide, volatile organic compounds, etc., in India increase the risk of respiratory diseases, COPD, asthma, and lung cancer."
The World Health Organization (WHO) has established stringent air quality standards to identify safe levels of pollution. According to these standards, the annual average for PM2.5 fine particulate matter should not exceed 5 µg/m³, and the 24-hour average should remain below 15 µg/m³. Nitrogen dioxide levels should remain under an annual average of 10 µg/m³ and a daily maximum of 25 µg/m³.
FROM GOOD TO HAZARDOUS AQI
In AQI terms, says Dr Nithin SG, consultant for medical oncology at CK Birla Hospital in New Delhi, the air quality is considered good and safe for all when the AQI is below 50. “When the AQI is between 50 and 100, the air quality is moderate, generally acceptable, but may affect sensitive individuals. An AQI ranging between 100-150 is unhealthy for sensitive groups, such as children, elderly individuals, and those with pre-existing conditions. When the AQI is in the 150-200 range, the air is unhealthy for everyone, causing widespread health issues. When the AQI breaches 200, the air is very unhealthy and poses serious risks to respiratory and cardiovascular health. An AQI above 300 indicates hazardous air, which can lead to severe health consequences even for healthy individuals," says Nithin.
In India, air pollution surpasses these recommended thresholds with alarming regularity posing a significant public health challenge as even brief exposure to heightened pollution levels can provoke asthma attacks, strokes, and respiratory infections.
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The Lancet Respiratory Medicine study on lung cancer in non-smokers is a validation of proof that we are suffering from pollution, says
Dr Rahul Sharma, additional director (pulmonology), Fortis Hospital, Noida.
“The situation is worse in north India. The world’s highest pollution levels are seen in some north Indian cities with PM 2.5 concentration often exceeding the safe limit whether it is winter or summer. This long-term exposure to fine particulate matter like nitrogen oxide and other pollutants is linked to the genetic mutation and chronic inflammation which usually leads to lung cancer, skin diseases and impacts other organs too. This finding actually reinforces the urgent need for strict pollution control measures in India," adds Sharma.
To support his argument for the urgent need to address the pollution problem, Sharma quotes a 2023 study published by the Energy Policy Institute at the University of Chicago, which found that Delhiites might lose up to 11.9 years of life expectancy due to air pollution. Pollution increases the chances of developing dangerous diseases at a young age, which makes it a long-term health problem for the nation. “The high level of PM2.5 causes not only lung cancer but chronic respiratory diseases, heart problems, lung problems, brain decline, weakened immunity, and it also affects our children by decreasing the lung capacity," he says.
AIR POLLUTION IS UNHEALTHY FOR AN ACTIVE LIFESTYLE
Since the pandemic, public messaging on health has stressed on exercise and better eating habits in order to improve immunity and health. However, pollution presents another challenge to people who have adopted an active lifestyle as outdoor exercise in a polluted environment causes high oxidative stress and inflammation. Exercise is always beneficial but in a highly polluted environment, it can do more harm than good due to increased inhalation of polluted air as exercise increases respiration and we take in more air.
“Running and cycling are outdoor activities that air pollution prohibits for it leads to exposure to high levels of particulate matter that might cause inflammatory conditions in the lungs and decrease oxygen uptake. Many urban Indians are fatigued, breathless, and suffer reduction in stamina because of chronic exposure to polluted air, thereby degrading fitness in the overall physical sense," notes Singhania.
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It’s not just outdoors where air pollution can affect people. Recently, American millionaire Bryan Johnson cut short a podcast with Zerodha founder Nikhil Kamath in a luxury hotel citing air pollution.
“Many individuals mistakenly believe that staying indoors offers protection from air pollution risks. However, research indicates that indoor air quality can occasionally be worse than that outside," says Singhania. Indoor pollutants originate from various sources, including the use of wood and coal for cooking, inadequate ventilation which can trap outdoor contaminants indoors leading to extended periods of exposure, and household items such as carpets, furniture, and certain cleaning agents may emit volatile organic compounds, which degrade indoor air quality further. Indoor pollution also increases when outdoor pollution levels are high. Fine particulate matter and harmful gases can seep into homes and offices, degrading indoor air quality, warns Nithin.
“To minimise exposure indoors, it’s essential to keep windows closed during peak pollution hours, use air purifiers, avoid burning biomass or candles indoors, and ensure adequate ventilation to reduce the buildup of harmful pollutants," advises Nithin.
Air pollution is no longer merely an environmental concern. It is directly affecting public health with rising lung cancer, heart disease, and lowering life expectancy. “India has been alerted by the recent Lancet study to act with immediate action in addressing air pollution. Though government policies and industrial reforms are called for, people need to take the initiative to minimise exposure and safeguard their health as well. Familiarity with the dangers, knowledge about air quality, and deliberate lifestyle modifications can enable Indians to tackle the rising pollution crisis better," says Singhania.
And perhaps, movies shot in Indian cities should henceforth come with the warning: “Breathing here is injurious to health."
Shrenik Avlani is a writer and editor and the co-author of The Shivfit Way, a book on functional fitness.
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