Why indoor air quality matters
Most people spend 80–90% of their time indoors, yet indoor air quality receives far less attention than outdoor pollution. Indoor VOC levels are consistently 2–5× higher than outdoors — from building materials, furniture, cleaning products, cooking, and occupants themselves. Poor indoor air quality is linked to respiratory problems, headaches, fatigue, and reduced cognitive performance.
1. Ventilate — the most effective step
Dilution with fresh outdoor air is the single most effective way to improve indoor air quality. Opening windows when outdoor air quality is good, using mechanical ventilation, and ensuring your HVAC system brings in adequate fresh air reduces all indoor pollutants simultaneously.
2. Remove sources
Before treating indoor air, address the sources. Choose low-VOC paints and finishes. Store cleaning products sealed. Avoid synthetic air fresheners — they add VOCs rather than removing them.
3. HEPA filtration for particles
HEPA filters remove particles — dust, pollen, pet dander, mould spores, and smoke particles. They do not remove gases or odours. For particulate pollution, a HEPA filter is essential.
Activated carbon and HEPA filtration are complementary — HEPA removes particles, carbon removes gases. The best air purifiers combine both. Either alone leaves a gap.
4. Activated carbon for gases and odours
For VOCs, odours, and gases — formaldehyde, benzene, cooking odours, pet smells — activated carbon is the right tool. Carbon filters in air purifiers work best when airflow is forced through the carbon bed at controlled velocity. The carbon must be replaced periodically as it becomes saturated.
5. Control humidity
High humidity (above 60%) promotes mould growth. Maintaining relative humidity between 40–60% reduces mould risk significantly — and a correctly sized air conditioner or dehumidifier is the most reliable way to achieve this.