While outdoor air pollution receives a lot of attention, the air inside our homes, workplaces, and schools is often just as polluted—sometimes even worse. Indoor air quality (IAQ) has a profound impact on our well-being, yet it remains underregulated and poorly understood. According to a detailed report by the UK Office of Science and Technology, there are significant gaps in both awareness and policy regarding the hazards we face indoors.

Although the EU’s Air Quality Framework Directive covers a wide range of airborne pollutants like nitrogen dioxide, carbon monoxide, and particulate matter, its focus lies almost entirely on outdoor air. In the UK, for instance, multiple agencies are responsible for regulating air, which creates confusion and leaves indoor air quality largely neglected.

Research into the health risks of indoor pollution is limited. Two of the most prominent studies in this field are:

• The Medical Research Council’s investigation into particulate matter’s effect on lung function.
• The Avon Longitudinal Study of Parents and Children, which collects environmental and genetic data from over 14,000 families.

However, even without exhaustive data, there’s already plenty of evidence that indoor air pollution is harmful—and that much can be done to reduce its effects.

According to the OST report, four key strategies should be prioritized:

1. Better coordination between regulatory bodies.
2. Updating building regulations to consider IAQ.
3. Reducing both indoor and outdoor emissions.
4. Raising public awareness and encouraging behavioral change.

Modern buildings are now constructed with energy conservation as a top priority. While this is great for sustainability, it often results in homes and offices that are highly insulated and tightly sealed—allowing little to no air exchange. Poor ventilation can lead to low oxygen levels, high humidity, and the accumulation of allergens like dust mites, mould, and chemical fumes.

The “passive house” concept offers one solution: high insulation combined with mechanical ventilation. Passive houses originated in Sweden and are designed to be both energy-efficient and health-conscious. Globally, more than 17,000 of these homes exist—including in the UK.

Still, ventilation alone isn’t enough. Introducing outdoor air may also introduce new pollutants, especially in urban environments with high levels of nitrogen oxides and particulates.

Indoor air can become contaminated from a surprising number of sources:

• Cooking and heating devices
• Building materials, furniture, and carpeting
• Household cleaners, air fresheners, and paints
• Outdoor pollution seeping indoors
• Radon gas rising from basements

Combustion appliances, in particular, are problematic—they release nitrogen oxides, carbon monoxide, and particulates. Volatile organic compounds (VOCs), often found in household products and materials, further add to the toxic mix. Unfortunately, many indoor pollutants are still understudied due to limited monitoring systems.

So what can be done right now?

• Install a high-efficiency air purifier, preferably one with a HEPA filter and activated carbon to trap both particles and gases.
• Control the sources of pollution: Use low-VOC products, limit soft furnishings that trap dust, and choose materials that don’t emit formaldehyde.
• Ventilate smartly: Open windows when outdoor air quality is good, but close them during high-traffic times.
• Maintain gas appliances: Regular servicing ensures they run efficiently and don’t emit toxic gases.
• Switch to electric cooking: This reduces the risk of indoor combustion-related emissions.

A case study in effective IAQ improvement comes from the 2007 UK smoking ban. In Scotland, hospital admissions for coronary syndromes fell by 17% for both smokers and non-smokers shortly after its introduction. Inspired by this, health experts now advocate for extending such bans to private vehicles, especially when children are present.

We don’t need to wait for new legislation to improve our indoor air. Every individual can take steps today to reduce indoor pollution and breathe cleaner, safer air. From improving ventilation and filtering the air, to changing consumer habits and appliance maintenance, the path to healthier indoor spaces is entirely achievable—and necessary.