Understanding indoor air quality can be complicated. The types and amounts of pollutants can vary between different buildings and even in different rooms of the same building. According to the UK Chief Medical Officer, indoor air quality is influenced by outdoor air, pollutants from inside sources, and chemical reactions indoors that create new pollutants. When buildings have poor ventilation, pollutants from indoor sources can become concentrated. Pollutants come from various sources like building materials, consumer products (scented candles, cooking, and cleaning products), and appliances (such as gas cookers and woodburning stoves). 

People typically spend 90 % of their time indoors in affluent countries, meaning that most of our exposure to airborne pollution occurs indoors. Harmful airborne pollutants can concentrate indoors. Poor air quality (indoors and outdoors) is estimated to cause an additional mortality burden of 26,000-38,000 deaths annually in the UK, so the impact on health can be significant. 

Numerous products and activities contribute to indoor air pollution. Examples of pollutants include nitrogen dioxide, particulate matter and carbon monoxide (from heating and cooking appliances), particulate matter and volatile organic compounds (from cooking) and other gaseous pollutants from cleaning products, air fresheners and fragrances. Certain types of pollutants, including nitrogen and carbon compounds and particulate matter (PM), can be found both indoors and outdoors but in varying concentrations and sometimes similar from processes (e.g. combustion). 

When we think of air pollution, we often picture industrial areas or congested city streets. However, the impact of outdoor air pollution does not simply stay outside. It has a significant influence on IAQ as well, mainly if a building is next to a busy road. Where a building is located on a busy road, it is better to open windows on the opposite side of the building to the road or out of rush hour times. 

It starts with reducing or eliminating sources of air pollutants. This can involve using low-emission building materials, choosing low-emission products, and properly ventilating indoor spaces to allow fresh air circulation.

Adequate ventilation is key to maintaining good IAQ. Opening windows, using extractor fans (especially in the kitchen and bathroom), or installing mechanical ventilation systems helps bring in fresh air and remove stale air, ensuring a continuous flow of clean air throughout the space.

Other actions you can take include using liquid, not spray cleaners, selecting low-VOC or VOC-free products for paints, adhesives, personal and consumer products (scented candles, air fresheners), and furnishings, and switching from gas to electric or induction hobs. You can use the cooking rings at the back of the hob, where the extractor fan is more effective. Always remember to ventilate and extract while cooking.

There is no overarching legislation on indoor air quality in the UK; however, several public health bodies have issued guidance on improving indoor air quality. 

Policymakers must implement science-based regulation to tackle various indoor pollutant sources, raise awareness about the importance of IAQ, establish guidelines for ventilation systems and construction materials, and enforce pollutant control measures. This will enhance IAQ, create healthier indoor environments, and safeguard public well-being.