For decades, lung cancer has been widely associated with cigarette smoking, leading many people to believe that non-smokers are largely protected from the disease. While tobacco remains the single biggest cause of lung cancer, a growing body of evidence suggests that many women, particularly those who have never smoked are being diagnosed with the disease due to a range of other risk factors. In many cases, these risks originate not in workplaces or polluted streets but within the home itself.
Women, especially in low- and middle-income countries, often spend a significant amount of time indoors carrying out household activities. Prolonged exposure to indoor air pollution, second-hand smoke, cooking fumes, and other environmental hazards can gradually damage the lungs over many years. These exposures may not receive the same attention as smoking, but experts say they deserve greater recognition as preventable contributors to lung cancer.
Lung Cancer Is Increasingly Being Diagnosed In Non-smokers
Although smoking accounts for the majority of lung cancer cases worldwide, researchers have observed a steady rise in diagnoses among people who have never smoked. Women make up a substantial proportion of these cases. This trend has prompted scientists to investigate environmental, biological, and lifestyle factors that may contribute to lung cancer in non-smokers.
Unlike smoking-related lung cancer, which often has a clear and identifiable cause, lung cancer in non-smokers typically develops due to a combination of long-term exposures and genetic susceptibility. As a result, many women remain unaware that they may be at risk until symptoms appear.
Dr. Vinayak Maka, Consultant, Department of Medical Oncology, Ramaiah Memorial Hospital said, “Ask most people what causes lung cancer and they will say smoking and they are not wrong. But here’s what doesn’t get talked about enough: plenty of women who’ve never smoked a cigarette in their lives are being diagnosed with it too. Often, the culprit isn’t tobacco at all. It’s something far more ordinary, which is the kitchen.”
Dr Maka also highlighted that cooking over biomass fuels, poor ventilation while frying or sautéing, years of breathing in second-hand smoke at home, and everyday indoor pollution, these all factors quietly work against the lungs, one meal, one year at a time. The scary part is how invisible this damage is. Nobody thinks twice about a smoky kitchen or a stuffy room. And that’s exactly why it goes unnoticed until it’s not.
Lung cancer, in its early stages, tends to be deceptively quiet. It can show up as a cough that just won’t go away, a little more breathlessness than usual when climbing stairs or walking briskly, an odd tightness in the chest, one chest infection after another, or a tiredness that doesn’t quite make sense given the day. Often, these get waved off, put down to the weather changing, being run down from stress, or “just a cold that’s taking its time to leave”.
Indoor Air Pollution: An Invisible Threat
Indoor air pollution is one of the most significant yet overlooked health hazards affecting women worldwide. Every day, cooking releases fine particulate matter, nitrogen dioxide, carbon monoxide, and a variety of chemical compounds into the air. In poorly ventilated kitchens, these pollutants can accumulate and remain suspended long after cooking has finished.
High-temperature cooking methods such as deep frying, stir-frying, grilling, and roasting generate cooking oil fumes that contain potentially harmful substances, including polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs). Repeated exposure to these fumes over several years may contribute to chronic inflammation within the lungs and increase the risk of cellular damage.
Women who prepare multiple meals daily in enclosed kitchens without proper ventilation may inhale these pollutants for several hours each day, making indoor cooking a significant source of long-term respiratory exposure.
The Continued Use Of Biomass Fuels
Despite improvements in access to cleaner cooking fuels, millions of households continue to rely on wood, charcoal, agricultural waste, and cow dung for cooking and heating. Burning these fuels produces dense smoke containing fine particulate matter and numerous toxic chemicals that penetrate deep into the lungs.
Women and young children are often the most heavily exposed because they spend more time near traditional cooking stoves. Years of inhaling biomass smoke have been linked to chronic respiratory diseases and are increasingly recognised as an important contributor to lung cancer among non-smoking women.
Transitioning to cleaner fuels such as LPG, piped natural gas, or electricity can substantially reduce indoor air pollution and improve long-term respiratory health.
Second-hand Smoke Is Not Harmless
Many women who have never smoked may still experience prolonged exposure to tobacco smoke through family members or colleagues. Second-hand smoke contains thousands of chemicals, including dozens of substances known to cause cancer.
Regular exposure at home can significantly increase the likelihood of developing lung cancer over time. The risk becomes greater when smoking occurs indoors without adequate ventilation, allowing harmful particles to remain suspended in the air and settle on household surfaces.
Creating smoke-free homes is therefore one of the most effective ways to reduce avoidable lung cancer risk among non-smoking family members.
Dr. (Prof.) Vishwanath S, Senior Consultant & Academic Advisor, Department of Medical Oncology, Apollo Hospitals, Bengaluru said, “Lung cancer is no longer a smoker’s disease. Out of two, 10 patients of lung cancer, we see around 3 to 4 women being diagnosed with lung cancer.”
Dr Vishwanath also emphasised that there are other factors why women are also susceptible for lung cancer. For instance, there are a lot of humans in rural areas of our country who are still using biomass, uh, uh, for cooking, which can also be a causative firefactor for lung cancer.
And also LPG, use of LPG and cooking in environments which have very poor ventilation can also be caused by lung cancer. And there are a lot of women who also make it exposed during occupations, which also have to be considered. And apart from that, of course, the outdoor air pollution, which may be a causative factor for non cancer.
Household Chemicals And Indoor Pollutants
Modern homes contain a variety of products that can contribute to indoor air pollution. Cleaning agents, aerosol sprays, paints, varnishes, incense sticks, mosquito coils, and scented candles release volatile organic compounds and other airborne chemicals into enclosed spaces.
Although occasional use is unlikely to pose a major risk, frequent exposure in poorly ventilated environments may contribute to cumulative respiratory irritation. Experts recommend ensuring adequate airflow while using such products and limiting unnecessary exposure wherever possible.
Radon: The Hidden Gas Few People Know About
Radon is a naturally occurring radioactive gas produced from the breakdown of uranium in soil and rocks. It can enter homes through cracks in floors, walls, and building foundations, particularly in areas with certain geological characteristics.
Because radon is colourless, odourless, and tasteless, people are usually unaware of its presence. Long-term exposure has been identified as one of the leading causes of lung cancer among non-smokers in several countries. Although radon testing is not yet common in many regions, awareness of this invisible hazard is gradually increasing.
Genetics May Also Play A Role
Not all women exposed to indoor pollutants develop lung cancer, suggesting that inherited genetic factors also influence individual risk. A family history of lung cancer may increase susceptibility, particularly when combined with environmental exposures.
Researchers are also investigating hormonal influences and genetic mutations that appear to occur more frequently in lung cancers affecting women who have never smoked. These discoveries are improving understanding of the disease and helping guide the development of targeted therapies.
Recognising Early Warning Signs
One of the challenges in diagnosing lung cancer among non-smokers is that both patients and healthcare providers may initially attribute symptoms to less serious conditions. As a result, diagnosis is sometimes delayed.
A persistent cough lasting more than three weeks is one of the earliest warning signs and should not be ignored. Other symptoms may include coughing up blood, unexplained breathlessness, persistent chest pain, recurrent chest infections, unexplained weight loss, fatigue, and a hoarse voice that does not improve.
Although these symptoms can result from several non-cancerous conditions, they warrant medical evaluation to identify the underlying cause.
Protecting Lung Health At Home
Reducing exposure to indoor air pollution can significantly improve respiratory health. Simple measures such as opening windows while cooking, installing chimneys or exhaust fans, and ensuring proper kitchen ventilation help remove harmful pollutants from indoor air.
Avoiding overheating cooking oils, choosing cleaner cooking methods such as steaming or boiling, and reducing the use of biomass fuels wherever possible can further lower exposure. Families should also maintain smoke-free homes and encourage smokers to quit or smoke only in designated outdoor areas.
Regular servicing of gas stoves ensures efficient combustion and reduces harmful emissions. Limiting the unnecessary use of incense, mosquito coils, and aerosol products in enclosed spaces also contributes to cleaner indoor air.
Why Awareness Matters
Public awareness campaigns have traditionally focused on smoking as the primary cause of lung cancer. While this remains essential, experts believe greater attention should also be given to environmental and household exposures that affect millions of women every day.
Understanding that lung cancer can develop in people who have never smoked encourages earlier medical consultation when symptoms appear and highlights the importance of improving indoor air quality. Awareness also empowers families to adopt healthier household practices that benefit everyone, particularly women, children, and older adults.
The Bottom Line
Smoking continues to be the leading cause of lung cancer, but it is not the only one. Indoor air pollution, cooking fumes, biomass smoke, second-hand tobacco smoke, household pollutants, radon exposure, and genetic factors can all contribute to lung cancer risk among women who have never smoked.
Recognising these hidden risks is the first step toward prevention. Improving ventilation, switching to cleaner cooking fuels, maintaining smoke-free homes and seeking medical attention for persistent respiratory symptoms can help reduce exposure and support earlier diagnosis. Protecting lung health begins not only by avoiding cigarettes but also by creating a cleaner and healthier home environment.
