Indoor air quality interacts with EMR exposure more than most people expect — both can independently contribute to oxidative stress, and addressing one without the other leaves real load on the table (see the Environmental Stressor Integration chapter for the full mechanism). This roadmap follows the same source-first logic as the rest of these guides.
Step 1 — Source Removal
Source removal does more than any filter ever will, because it stops the problem at its origin rather than managing it after the fact.
- Eliminate fragranced products (air fresheners, scented candles, heavily fragranced cleaning products) — a surprisingly large and consistently underestimated VOC source
- Remove active mould sources (see the Mould Prevention Basics guide)
- Avoid combustion indoors where avoidable (gas cooktops, unflued heaters)
- Reduce dust reservoirs — carpets, soft furnishings, and clutter all trap and re-release particulates rather than simply holding them inertly
Step 2 — Ventilation
- Open windows daily, even briefly — a few minutes of cross-ventilation measurably resets indoor pollutant concentrations
- Use exhaust fans in kitchens and bathrooms
- Ensure cross-ventilation where the floor plan allows it
- Consider a heat/energy recovery ventilator (HRV/ERV) for airtight modern builds, which trap moisture and pollutants far more than older, leakier construction ever did
Step 3 — Filtration
- HEPA filtration for particulates
- Activated carbon filtration for VOCs — a HEPA filter alone does nothing for gases, since it's designed to trap particles, not adsorb chemical vapours
- Maintain and replace filters on schedule — a neglected filter can become a pollutant source itself, releasing back what it's already accumulated
Step 4 — Humidity Control
- Maintain 40–60% relative humidity
- Use dehumidifiers where needed
- Fix leaks promptly
- Improve insulation to reduce condensation risk — condensation on a cold surface is one of the most common, least-suspected sources of a slow-building mould problem
As with EMR, source removal and ventilation (free or low-cost) do most of the work — filtration and mechanical solutions are for what's left over.