How to Improve Indoor Air Quality: A Practical Guide
Most people in the UK spend roughly 90 per cent of their time indoors. Yet indoor air quality receives far less attention than outdoor pollution, despite the fact that indoor air in typical homes and offices can contain concentrations of certain pollutants several times higher than outdoor air. For anyone interested in their health environment, understanding how to improve indoor air quality is both practical and worthwhile.
Why Indoor Air Quality Matters
The body processes air continuously, and the quality of that air has physiological effects. Poor indoor air quality is associated with a range of health impacts, including respiratory irritation, headaches, fatigue, disrupted sleep, and exacerbation of allergies and asthma. The UK Government recognises indoor air pollution as a significant public health issue, with sources including building materials, furnishings, cleaning products, cooking, mould, and inadequate ventilation all contributing to the indoor pollutant load.
Sleep quality is particularly sensitive to air quality. CO2 accumulation in unventilated bedrooms during sleep has been shown in multiple studies to increase arousal frequency, reduce slow-wave sleep, and impair next-day cognitive performance. For anyone working to optimise their sleep, improving bedroom air quality is one of the more direct environmental levers available.
The Main Indoor Air Pollutants to Address
Volatile organic compounds (VOCs): Released by paints, varnishes, adhesives, cleaning products, air fresheners, and many synthetic furnishings. Many VOCs cause eye, nose, and throat irritation at high concentrations. They off-gas most heavily when products are new. Good ventilation is the primary mitigation.
Carbon dioxide (CO2): A natural byproduct of breathing. In poorly ventilated rooms, particularly bedrooms at night, CO2 can accumulate to levels that impair sleep quality and cognitive function. This is not a pollutant per se but a marker of inadequate fresh-air exchange.
Particulate matter (PM2.5 and PM10): Fine particles from cooking, candles, incense, smoking, and outdoor pollution that infiltrate indoors. Associated with respiratory and cardiovascular effects at sustained elevated exposures.
Mould and biological pollutants: Mould spores thrive in damp conditions, particularly bathrooms, kitchens, and rooms with inadequate ventilation or condensation. Mould can cause and exacerbate respiratory conditions and allergies.
Nitrogen dioxide (NO2): Released by gas cookers and boilers. Consistently high in kitchens with poor extraction. A known respiratory irritant.
Practical Steps to Improve Indoor Air Quality
Ventilate consistently: Open windows daily, even in winter. Cross-ventilation (opening windows on opposite sides of a room or building) exchanges air most efficiently. Use trickle vents if available. When cooking with gas, always use extraction fans or open windows.
Control moisture and prevent mould: Use extractor fans in bathrooms and kitchens, open windows after showering, and address any condensation or water ingress promptly. Maintaining indoor relative humidity between 40 and 60 per cent reduces both mould growth and dust mite populations.
Choose low-VOC products: Where practical, choose low-VOC paints, adhesives, and cleaning products. Allow new furniture and furnishings to off-gas in a ventilated space before use. Avoid synthetic air fresheners, which often add VOC load without improving air quality.
Use an air purifier where relevant: HEPA-filter air purifiers can meaningfully reduce particulate matter in a room, and are particularly useful in urban settings with high outdoor PM2.5 levels or in homes where allergens are a concern. They do not remove CO2 or VOCs effectively, so ventilation remains the foundational measure.
Consider a CO2 monitor: Inexpensive CO2 monitors have become widely available in the UK. Placing one in your bedroom provides direct feedback on overnight CO2 accumulation and gives you concrete data on whether your ventilation strategy is working.
Plants and Indoor Air Quality: What the Evidence Shows
The idea that houseplants meaningfully improve indoor air quality originates from a 1989 NASA study and has been widely cited in wellness contexts ever since. The evidence, however, does not support the claims made for domestic settings. The NASA study was conducted in sealed laboratory conditions with significantly higher plant density than any practical home environment would have. A 2019 review in the Journal of Exposure Science concluded that you would need between 10 and 1,000 plants per square metre to approach the air-cleaning effects of opening a window. Plants are pleasant additions to a home for many reasons. Measurably improving air quality is not among them at normal density.
AEQUIL® and the Sleep Environment
The bedroom environment, including temperature, light, sound and air quality, can influence how conducive a space feels for rest. Frédéric Roscop, AEQUIL®’s founder and a qualified osteopath, designed the BE RESTED® cosmetic patch as a sensory element within an intentional evening routine. Practical choices such as reducing light, keeping the room comfortably cool and allowing fresh air to circulate can sit alongside it as part of a more considered setting for the night ahead.
Disclaimer: This article is for informational purposes only and is not intended as medical advice, diagnosis, or treatment. If you have concerns about air quality, respiratory symptoms, or related health issues, consult a qualified healthcare professional.