Easy and Affordable Ways to Improve Indoor Air Quality

Start with sources and ventilation

Indoor air can contain a mix of things: moisture, cooking fumes, dust, pet dander, pollen that has come in from outside, and gases released by products and materials. Most guidance from health and building bodies follows the same order of priorities: remove or reduce the source of the problem, then ventilate, and only then consider air-cleaning devices. This order is also usually the cheapest.

This article is general information, not medical or professional advice. If you or someone in your home has asthma or another respiratory condition, a doctor or pharmacist is the right person to ask about symptoms.

Reduce sources

Some sources are easy to cut back on:

• Tobacco smoke: smoking indoors is a major indoor pollutant. Smoking outside is far better for the people inside.
• Combustion: unflued gas heaters, candles, incense and open fires add particles and gases. Wood burners and open fires can add particles to the room if they leak or are used badly, and the trade-offs of wood burners are worth understanding before you rely on one.
• Cooking: frying and grilling produce fumes and particles, and gas hobs release combustion gases.
• Products: some sprays, solvent-based cleaners, air fresheners and new furnishings release volatile organic compounds (VOCs). Choosing unscented products where possible and using natural air fresheners sparingly may help, though “natural” does not automatically mean harmless. Fragrance sensitivity is common, and scented products can bother some people.
• Decorating: fresh paint and glues can release fumes for a while, so low-VOC paint is a reasonable choice when you decorate.

Ventilate, and manage moisture

Fresh air dilutes whatever has built up indoors. Opening windows for a few minutes, ideally on opposite sides of the home to create a through-draught, is often a very effective, free approach. In cold weather, short bursts of ventilation are usually better than leaving a window ajar all day, because they let stale air out without cooling the whole house.

• Use extractor fans in kitchens and bathrooms, and let them run for a while after cooking or showering. Fans should vent outdoors, not into a loft.
• Keep trickle vents open if your windows have them.
• Dry laundry outdoors where you can, or in a well-ventilated room, because wet clothes release a lot of moisture into the air. The same goes for clothes drying choices more generally.
• Keep furniture slightly away from external walls so air can circulate.

Moisture matters because damp conditions encourage mould and dust mites. This is closely linked to condensation control, which is influenced by heating, insulation and airflow. There can be a tension between saving heat and ventilating well: draught proofing helps reduce energy waste, but sealed homes still need a planned way to let air out and in, such as vents and extractor fans.

Filters: useful in some situations

Portable air cleaners with HEPA filters can remove fine particles from the air in a room. They may be useful for people with allergies or those living near busy roads or in areas affected by smoke, but they do not remove all gases, and they do nothing about the source. A device that is too small for the room, or whose filters are not replaced, will do little. Treat claims of dramatic health benefits cautiously and check the advertised room size and filter details. Models that produce ozone should be avoided.

Cleaning or replacing the filter in a cooker hood and vacuuming with a machine that has a good filter can all reduce dust. Damp-dusting is generally better than dry dusting, which can just move dust around.

Plants: nice to have, not a fix

Houseplants are often promoted as air purifiers. Some laboratory studies show plants can take up certain compounds, but conditions in sealed test chambers are very different from real rooms, and the general view is that ordinary houseplants make little measurable difference to air quality in a normal home. They can still be pleasant to have, but ventilation does far more.

When to call a professional

Some problems are beyond DIY:

• Gas appliances: gas boilers, cookers and heaters must be installed and serviced by a suitably qualified engineer. Carbon monoxide is odourless and can be dangerous, so a working carbon monoxide alarm is strongly recommended in homes with fuel-burning appliances. If an alarm sounds or you feel unwell with headache, dizziness or nausea, get fresh air immediately and seek urgent help. Never ignore a gas smell; follow the emergency advice of your gas supplier.
• Persistent damp and mould: a small patch of surface mould can often be wiped off carefully, but large areas, mould that keeps returning, or mould linked to leaks or structural damp need the cause to be found and fixed. Do not mix cleaning products when treating it, particularly bleach with anything else.
• Older buildings: disturbing old paint or materials during works can release hazardous dust, as covered under renovation hazards.
• Radon: in some regions radon gas builds up in buildings. Local health or housing agencies usually have information on whether it affects your area and how to test.

A sensible order of action

1. Stop smoking indoors and reduce combustion and fragrance sources.
2. Ventilate routinely, especially while cooking, showering and drying clothes.
3. Fix leaks and manage moisture.
4. Keep up cleaning with a damp cloth and a filtered vacuum.
5. Consider a filter if you have a specific need.
6. Call a professional for gas appliances, persistent mould or suspected hazards.

Measures like these cost little, and most of them also help the home work better as a whole. Effects on health vary from person to person, and air quality outdoors also matters, so no single step guarantees results.