The Silent Threat Inside: How Indoor Air Pollution is Damaging Our Lungs?

Sabika Shrestha

While the winter smog blanketing the Kathmandu Valley frequently captures public attention, health experts are issuing urgent warnings about a more intimate danger: the air inside our homes. Recent data from global health authorities indicates that indoor air pollution contributes to millions of premature deaths worldwide each year.

In Nepal, this crisis uniquely spans both rural and urban divides. In many rural communities, the continued reliance on traditional biomass fuels—such as firewood and agricultural waste—for cooking creates highly toxic indoor environments.

Conversely, in rapidly urbanizing areas, tightly sealed modern apartments trap chemical pollutants from synthetic furnishings, cleaning products, and gas heaters, creating a dangerous and invisible cocktail of toxins.

Medical professionals caution that the air inside our homes can often be significantly more polluted than the air outside.

Dr. Sneha Bandhu Regmi, Consultant Pulmonologist at Tribhuvan University Teaching Hospital, says indoor environments themselves can be major sources of harmful air pollutants.

“When we cook using firewood, gas, or petroleum, combustion releases a large amount of particulate matter. Even the vapors and fumes coming from heated oil and utensils add to indoor pollution. In addition, homes with underground spaces or structural crevices can accumulate radon gas, a potential carcinogen that increases the risk of lung cancer with long-term exposure. Unattended areas like storerooms often harbor mold, which can trigger hypersensitivity reactions and make people more prone to allergic diseases,” she explains.

In colder months, closed windows trap indoor pollutants like PM2.5 and VOCs. When inhaled, they reach deep into the lungs, because inflammation, and over time can enter the bloodstream, leading to serious and sometimes permanent health problems.

Pulmonologists are seeing more cases of COPD in non-smokers, mainly due to long-term exposure to kitchen smoke and poor indoor air quality.

Invisible pollutants such as mold spores, pet dander, and nitrogen dioxide from unvented gas stoves can also trigger severe asthma attacks.

For young children who spend most of their time indoors, the risks are even greater. Continuous exposure can slow lung development and increase the chances of serious infections like pneumonia, which is still a leading cause of child deaths in Nepal.

This indoor vulnerability is further exacerbated by the worsening outdoor air quality. When outdoor levels are high, the pollutants inevitably seep into homes, compounding the risks already present from indoor sources.

Speaking on the long-term health impacts, Dr. Regmi adds, “Fine particulate matter, especially particles smaller than 2.5 micrometers (PM2.5), can easily enter the lungs and pass into the bloodstream. Once in circulation, these tiny particles can affect multiple organs — including the brain, heart, kidneys, and pancreas — leading to widespread and serious health consequences over time.”

Environmental scientists and public health officials are urging the public to take immediate, practical measures to safeguard their health.

Simple, everyday actions such as ensuring proper cross-ventilation during hours when outdoor pollution is lower, running exhaust fans while cooking, and promptly fixing damp areas to prevent mold can drastically reduce lung exposure.

Furthermore, the ongoing national push to transition households toward clean electric cooking technologies, such as induction stoves, is being championed as a vital step in eradicating the burden of household air pollution.

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