Indoor air pollution: The invisible killer at home

When air pollution is discussed in Bangladesh, attention usually turns to black smoke from vehicles, brick kilns, factories, construction dust and traffic congestion. Every winter, Dhaka repeatedly ranks among the world's most polluted cities, prompting public concern and media coverage. Yet one of the country's most dangerous environmental threats remains largely invisible because it exists inside our homes.

Indoor air pollution has quietly become a major public health crisis, disproportionately harming women, children and the elderly who spend most of their time indoors.

A home should be a place of comfort, safety and protection. Unfortunately, for millions of urban families in Bangladesh, the air inside their homes is often more polluted than the air outside. Invisible pollutants released from cooking, gas burners, poor ventilation, damp walls, household chemicals, tobacco smoke and overcrowded living conditions gradually damage health. Since women, infants, young children, pregnant mothers, elderly people and those working from home spend longer hours indoors, they receive the highest exposure and face the greatest health risks.

The scale of the problem is alarming. According to the World Health Organisation (WHO), household air pollution causes approximately 3.2 million premature deaths globally every year, including more than 237,000 deaths among children under five. While Bangladesh has made significant progress in replacing biomass fuels with natural gas and liquefied petroleum gas (LPG) in urban households, indoor pollution remains widespread because of poor ventilation, gas leaks, emissions from cooking, damp housing conditions and chemical pollutants found in everyday household products.

Bangladesh is urbanising rapidly. According to the United Nations, more than 76 million people, representing around 43 per cent of the country''s population, now live in urban areas. This proportion is projected to exceed half of the national population within the next two decades. Unfortunately, the quality of urban housing has not kept pace with this rapid growth. Thousands of apartment buildings are constructed with little consideration for natural ventilation, healthy airflow or indoor environmental quality.

Poor building design is one of the principal causes of indoor air pollution. Many apartments have enclosed kitchens without proper exhaust systems, while bedrooms receive limited fresh air because buildings are constructed too close together. To avoid outdoor dust, traffic noise, mosquitoes, heat and security concerns, many families keep their windows closed throughout the day. As a result, polluted air remains trapped inside living spaces, exposing residents continuously to harmful contaminants.

Cooking is another major source of indoor pollution. Although natural gas and LPG are cleaner than traditional biomass fuels, gas burners still emit harmful pollutants including nitrogen dioxide, carbon monoxide, methane, formaldehyde and fine particulate matter, especially when burners are poorly maintained or combustion is incomplete. International studies have shown that gas stoves can leak methane even when switched off due to faulty valves and pipelines.

Cooking oil heated at high temperatures also releases microscopic particles that remain suspended in indoor air for hours. Frying, grilling and roasting foods generate particularly high concentrations of airborne pollutants if kitchens lack adequate ventilation.

Indoor dampness further degrades air quality. Water leakage, humid bathrooms, poor drainage and insufficient sunlight encourage the growth of mould, fungi, bacteria and dust mites. These biological pollutants trigger asthma, allergies and respiratory infections. Synthetic furniture, fresh paint, carpets, adhesives, plastic products, mosquito coils, incense sticks, scented candles, aerosol sprays and many household cleaning products release volatile organic compounds that contaminate indoor air and may affect human health over time.

The health consequences are severe. Indoor air pollution contributes to asthma, pneumonia, bronchitis, chronic obstructive pulmonary disease, lung infections, allergic rhinitis, chronic cough, sore throat, sinusitis, eye irritation, skin diseases and weakened immune function. Medical research published in The Lancet and the Global Burden of Disease Study has also linked long term exposure to indoor fine particulate matter with heart disease, hypertension, stroke, diabetes, chronic kidney disease and lung cancer. Fine particles enter the bloodstream through the lungs, causing inflammation that damages blood vessels and vital organs.

Pregnant women face particularly serious risks. Exposure to carbon monoxide, nitrogen dioxide and fine particulate matter has been associated with miscarriage, premature birth, low birth weight, impaired fetal development and stillbirth. Indoor pollution may also increase the likelihood of pregnancy complications, including maternal hypertension.

Children are especially vulnerable because their lungs and immune systems are still developing. They breathe more rapidly than adults, meaning they inhale proportionately more pollutants. Scientific evidence indicates that prolonged exposure to polluted indoor air can reduce lung growth, impair brain development, weaken memory and concentration, increase respiratory infections and lower academic performance through frequent school absenteeism. Repeated exposure during childhood can also increase the risk of chronic respiratory diseases later in life.

Older adults are equally at risk. Those suffering from heart disease, diabetes, asthma or chronic lung conditions often experience worsening symptoms when exposed to polluted indoor air. Hospital admissions among elderly people increase significantly during periods of poor indoor air quality.

Indoor pollution also affects mental wellbeing. Poor ventilation allows carbon dioxide levels to rise while oxygen concentrations decline, causing headaches, dizziness, fatigue, poor sleep quality, stress, anxiety, irritability and reduced concentration. For children studying in poorly ventilated rooms, inadequate oxygen supply may reduce learning capacity and cognitive performance.

The economic consequences are equally significant. Families spend substantial amounts on medical consultations, medicines, diagnostic tests, hospital admissions and long term treatment for preventable diseases. Parents lose income while caring for sick children, and businesses suffer productivity losses because of repeated illness.

According to the World Bank, air pollution costs Bangladesh billions of dollars every year through healthcare expenditure, reduced productivity and premature deaths. Although most analyses focus on outdoor pollution, improving indoor air quality could substantially reduce these economic losses.

Many developed countries have successfully addressed indoor air pollution through strong regulation and public awareness. Sweden and Germany require residential buildings to meet strict standards for ventilation, insulation and moisture control. Japan introduced regulations limiting emissions of formaldehyde and other harmful chemicals from construction materials following widespread concerns over Sick Building Syndrome.

Singapore enforces modern building codes that require effective ventilation systems in residential and commercial buildings. Canada incorporates indoor air quality standards into national building regulations while educating homeowners about ventilation, gas safety and indoor pollutants. These experiences demonstrate that healthier homes are achievable through effective government regulation, scientific monitoring and public education.

Bangladesh can learn from these international experiences while adapting solutions to local realities. The country already has the Bangladesh National Building Code (BNBC) and other environmental regulations, but enforcement remains weak. Building inspections often focus primarily on structural safety rather than healthy indoor living conditions. Ventilation, kitchen design, moisture control, gas safety and indoor air quality receive inadequate attention during planning and construction.

Addressing this silent crisis requires stronger coordination among the Ministry of Housing and Public Works, Rajdhani Unnayan Kartripakkha (RAJUK), city corporations, municipalities, the Department of Environment, the Department of Public Health Engineering, gas distribution companies and the Fire Service. Housing authorities should require all residential buildings to meet minimum ventilation standards before issuing occupancy certificates. Developers who ignore building codes should face substantial financial penalties.

Gas distribution companies should regularly inspect household pipelines, regulators, burners and valves to detect leaks and ensure safe combustion. The Department of Environment should establish national indoor air quality standards consistent with WHO guidelines and regularly monitor pollution levels inside apartments, schools, hospitals and childcare centres. Universities and research institutions should conduct nationwide studies to generate reliable evidence for policymaking.

Public awareness is equally important. Healthcare professionals should educate patients about indoor air pollution during routine consultations. Schools should teach students practical ways to improve indoor air quality, while television, newspapers and social media should promote awareness campaigns highlighting the hidden dangers inside homes.

Individual households can also play an important role by opening windows whenever outdoor conditions permit, installing kitchen exhaust fans, maintaining gas burners regularly, repairing gas leaks immediately, reducing the use of mosquito coils and aerosol sprays, controlling dampness, cleaning air conditioner filters, allowing sunlight into rooms and avoiding smoking indoors.

As Bangladesh advances towards becoming an upper middle income nation, healthy housing must become a cornerstone of sustainable urban development. Cities should provide not only concrete buildings but also homes where families can breathe safely and live healthy lives. Every woman deserves to prepare meals without inhaling harmful pollutants.

Every child deserves clean indoor air that supports healthy lungs, strong immunity and proper physical and mental development. Clean air should not end at the front door. It must begin inside every home, where the health of Bangladesh's future generations is being shaped every single day.

*   The writer is the Editor and CEO of News Network