For decades, indoor air pollution has lived in the shadow of the more visible crisis of outdoor smog. Cities like Delhi and Mumbai dominate global lists of the world’s most polluted urban centres, drawing
attention to factories, traffic emissions, and construction dust. Yet scientists have long warned that the air inside homes may be just as dangerous, and sometimes far worse.
A major new study by Stanford University highlighted in The New York Post suggests that gas and propane stoves, commonly used in millions of homes worldwide, emit hazardous pollutants like nitrogen dioxide (NO₂) and benzene — both strongly linked to chronic respiratory illnesses, childhood asthma, heart disease, type 2 diabetes, and even certain cancers.
In India, where indoor air pollution is a leading cause of premature death, the findings raise an urgent question: Could everyday cooking be quietly damaging the health of millions?
What The New Stanford Research Says
The study examined emissions from gas and propane stoves, including those that are properly functioning and installed. What it found was deeply unsettling. Even without obvious leaks, the stoves released high levels of nitrogen dioxide (NO₂) — a pollutant known to exacerbate respiratory diseases — and benzene, a carcinogenic chemical associated with increased risks of leukaemia and other cancers.
Researchers noted that during routine cooking, indoor NO₂ levels often surpass internationally accepted health safety thresholds, sometimes exceeding the limits set for outdoor pollution. Benzene concentrations, too, rose sharply in enclosed spaces and lingered long after the stove was turned off.
The study also highlighted that exposure is not uniform. Children, elderly individuals, and people with existing respiratory conditions face significantly higher risks. Small, poorly ventilated kitchens — common in urban apartments and lower-income households — are particularly vulnerable.
Why This Matters For India
At first glance, this may seem like a Western household issue linked to gas infrastructure debates. But India’s situation is far more complex and potentially more dangerous.
India ranks among the countries with the highest indoor air pollution burden in the world. While the push for LPG connections under schemes like Ujjwala has improved access to cleaner fuels, many still rely on biomass, coal, kerosene, and mixed-fuel cooking. Even in LPG-only kitchens, poor ventilation and small enclosed spaces create dangerous build-ups of pollutants.
In many Indian cities, the average household spends more time indoors due to outdoor pollution, ironically exposing themselves to high levels of indoor pollutants. Unlike the spacious, better-ventilated homes targeted in many Western studies, Indian kitchens are smaller, hotter, and less ventilated, often lacking chimneys or exhaust systems.
This makes pollutants like NO₂ and benzene more concentrated, potentially compounding the risks identified by the Stanford research.
How NO₂ And Benzene Harm The Body
Nitrogen dioxide and benzene are not new villains in environmental health research. Both have been studied for decades and are known to have long-lasting and cumulative effects on human health.
NO₂ is a highly reactive gas that irritates the lining of the lungs. Prolonged exposure inflames airways, reduces lung function, and triggers asthma attacks. Numerous studies link chronic NO₂ exposure to increased hospitalisations for respiratory illness, greater risk of cardiovascular disease, and higher mortality rates.
For roughly 35 million Indians suffering from asthma, NO₂ exposure is especially harmful. Even short-term spikes can cause wheezing, chest tightness, and reduced oxygen saturation.
Benzene, on the other hand, is listed as a Group 1 carcinogen, meaning it is known to cause cancer in humans. Long-term benzene exposure is associated with blood disorders, suppressed immune function and various forms of leukemia. Because benzene accumulates in fat tissue, it can remain in the body for extended periods.
In kitchens without proper ventilation, concentrations of these chemicals can rise dramatically during everyday activities like boiling milk, frying vegetables, or making rotis.
Gas Stoves vs. Indian Cooking Habits: A Recipe For Higher Exposure?
Indian cooking involves high-heat techniques such as frying, tempering, grilling, and pressure-cooking — all of which generate more particulate matter and gaseous emissions compared to typical Western cooking.
A simple ‘tadka’ can release fine particulate matter at rates that equal or exceed outdoor Delhi pollution levels on a bad winter day. Combine this with gas combustion, and the result is a dense cloud of invisible pollutants trapped in small kitchens.
Because many Indian households cook several hot meals a day, the duration of exposure is also higher. Women, homemakers, domestic workers, and elderly household members often spend extended hours in the kitchen, making them more vulnerable to health risks.
Are Indian Homes Equipped To Handle Pollutants?
Ventilation is the single biggest factor that can reduce indoor pollution levels. Yet many Indian homes fall short on this front.
A large proportion of urban kitchens lack chimneys altogether. Even when chimneys are installed, they are often poorly maintained or used infrequently. Windows are uncommon in rental apartments, and new real-estate developments in crowded cities prioritise space-saving over airflow.
Some households rely solely on ceiling fans or open doors, which may not be adequate for clearing out pollutants like NO₂ or benzene. Exhaust fans, when present, are often too weak to make a measurable difference.
This means the pollutants identified in the Stanford study may remain trapped for hours, or even accumulate over months, inside Indian homes.
What Are Other Countries Doing?
The findings have accelerated a global shift towards electrification in developed countries. In the US, cities such as New York, Berkeley, Los Angeles, and Seattle have imposed restrictions on new gas stove installations. The European Union is debating stricter indoor air quality regulations and potential phase-outs of gas appliances in the long term.
These policy moves stem from decades of research linking gas stoves to childhood asthma and respiratory illness, and now, to potential cancer risks. Electrification is seen not only as a climate-friendly alternative but as a public health necessity.
India has not yet entered this policy debate at a national level. But as urbanisation increases, and as millions move into smaller apartments, the country may soon face similar questions about whether current standards for kitchen ventilation, building design, and fuel choice are adequate.
Indoor Air Pollution vs Outdoor Air Pollution: Which Is Worse?
It may be surprising, but several studies show that indoor air can be two to five times more polluted than outdoor air, even in highly polluted cities. This is because outdoor pollutants mix with indoor emissions from cooking, cleaning agents, incense sticks, mosquito coils and scented candles — creating a toxic cocktail.
In winter months, when houses remain closed, air circulation decreases dramatically. This is the period when respiratory illnesses spike in India, and indoor pollution significantly contributes to that surge.
For families that use gas stoves, incense sticks, and mosquito coils simultaneously, pollutant levels can rise exponentially.
What Indian Experts Say About The Risks
Pulmonologists in India have long warned that indoor air is a silent killer. While the conversation has centred mainly on soot and particulate matter from biomass and kerosene, many now believe the focus must expand to gas emissions as well.
Lung specialists note that chronic exposure to NO₂ and benzene can have cumulative effects that are not always obvious in the short term. Coughing, wheezing, morning throat irritation, and recurring colds are often early signs of long-term exposure.
Environmental health researchers argue that India’s indoor air quality problem is significantly understudied compared to outdoor pollution. They stress that in a country with rising cancer rates, diabetes, and respiratory illness, every additional exposure pathway needs scrutiny.
Several reports point out that ventilation standards have not kept pace with shrinking home sizes. Many households lack the structural design to safely disperse cooking emissions, creating a public health risk that spans socio-economic boundaries.
What Can Households Do?
While long-term policy change may take time, households can take simple steps to reduce exposure.
Ventilation: Keeping windows open while cooking, using an exhaust fan, and ensuring air circulation can significantly reduce pollutant concentrations. Installing a chimney and cleaning it regularly is especially effective for kitchens that see heavy use.
Induction Or Electric Cooking: Changing the cooking method for some meals can reduce exposure to gas combustion by-products. Even partial electrification can make a noticeable difference.
Avoid Multiple Pollutants: Households should also avoid combining multiple indoor pollutants at the same time, such as incense sticks, mosquito coils, and gas cooking.
Regular Servicing Of LPG Stoves: This can help prevent leaks that worsen air quality. And families can consider portable air purifiers, especially for vulnerable individuals.
What To Conclude?
The new research makes one point clear: the greatest health risks in your home may come from the most ordinary activities, such as lighting your stove, boiling your tea, and frying your lunch.
The question now is whether India will treat this as a private household problem or a public health issue requiring national attention.
As scientists increasingly warn, the air you breathe while cooking may shape your long-term health just as much as the air you breathe outside your front door.
