How to improve your indoor air quality at home

Air quality can be more than three times worse indoors than outdoors, according to a study by UK air pollution campaign Clean Air Day. In our guide, we explain what you can do to improve your indoor air quality at home.

We all know that outdoor pollution is a problem, but the chances are you're not too worried about the quality of air in your home. However, many of the things we do to make our homes more comfortable, such as decorating, lighting candles and using air fresheners, can increase our exposure to pollutants – and contribute significantly to our collective national emissions.

Read on to discover the various types of indoor air pollution and what steps you can take to reduce pollution in your home.

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Indoor air pollution puts our health at risk

Even if you're currently healthy, you're at risk of developing health problems as a result of breathing in polluted indoor air. 

Older people and those with health conditions such as asthma, heart disease or chronic obstructive pulmonary disease (COPD) are particularly vulnerable to the effects of pollution. 

Children and young adults are also more vulnerable, because they have faster breathing rates and their lungs are still developing.

Types of indoor air pollution

There are three main types of pollution in our homes: particulate matter (PM), gases and volatile organic compounds (VOCs).

Particulate matter (PM)

Particulate matter is generated as a by-product of combustion or, in other words, when you burn something. This can be when you use a wood or coal fire, but also when you burn candles, use an electric toaster or cook with gas.

In theory, regular cleaning can help to get rid of it. But cleaning 'the wrong way' risks stirring up particulate matter that's settled as dust, and lifting it into the air. This can happen if you dry dust, or use a poorly performing vacuum cleaner. Look for a vacuum cleaner with good allergen retention, and dust with a damp cloth if possible to prevent this happening. 

Particulate matter can inflame your airways and increase the risk of lung and heart disease if inhaled at persistently high levels over time.

Discover which vacuum cleaners effectively deal with allergens in our guide to the best vacuum cleaners

Gases

Appliances that burn fuel emit gases including carbon dioxide (CO2), nitrogen dioxide (NO2) and carbon monoxide (CO).

• CO2 is produced by human respiration and burners operating normally. Breathing in high levels of CO2 over time, which come from poor ventilation, can result in drowsiness, impaired thinking, dizziness and headaches.
• NO2 is produced by combustion. In homes with gas stoves, kerosene heaters or unvented gas-space heaters, indoor levels of NO2 often exceed outdoor levels. This can increase the sensitivity of your airways, making the body more likely to have a reaction. It can also exacerbate the effects of exposure to allergens such as house dust mites, and irritate the eyes, nose, throat and respiratory tract.
• CO is produced when carbon-containing fuel burns without adequate oxygen – for example, by poorly maintained gas heaters and boilers, portable gas or paraffin heaters with no flue, and badly installed stoves. CO is an odourless but potentially deadly gas. Every home should have at least one working carbon monoxide detector, correctly positioned.

Not every carbon monoxide detector is up to the job of protecting you and your family. In fact, our expert tests have uncovered models that you can't rely on to detect the gas and sound the alarm. Check our guide to the best carbon monoxide detectors

Volatile Organic Compounds (VOCs)

Volatile organic compounds are chemicals found in a wide variety of materials. They're produced when cooking, using heating appliances such as wood burners and non-electric space heaters, and using paint or furniture polish. VOCs evaporate into the air at room temperature, forming vapours that we breathe.

Different classes of VOCs have different risk levels. For example, benzene is a carcinogen (from petrol and cigarette smoke and, potentially, from paints and solvents) and is high risk. Terpenes, including limonene and pinene (familiar lemon and pine smells used in scented toiletries and bathroom cleaners), are considered lower risk albeit still not good for you to breathe in. 

VOCs can react with ozone from outdoor air, particularly in hot weather, to form the gas formaldehyde and other irritants. Formaldehyde is a lung irritant that can cause allergic reactions and, at very high levels, is carcinogenic. Formaldehyde can also be released from new flatpack furniture, lino, carpet, fabrics, bedding, glues and insulation. 

Exposure to very high levels of VOCs can cause symptoms such as eye, nose and throat irritation, headaches and nausea and, in the long term, damage the liver, kidneys and central nervous system. 

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12 tips to reduce pollution in your home

If you're concerned about the air quality in your home, you might assume you need an air purifier. If you're shopping for an air one, consult our expert air purifier reviews.

However, an air purifier shouldn't be your first line of defence against pollution. The most important thing you can do when it comes to air quality, for yourself and others, is to reduce the amount of pollution you generate. 

See our top tips below to improve your home's air quality.

1. Open your windows – but be strategic

Opening your windows regularly removes polluting particles from the air in your living space and lets in fresh air. Don't forget to do this in winter when humidity is high, however tempting it is to keep all windows tightly closed.

You need to be strategic about when you open your windows, though. If you live near a busy road, keep them closed at peak traffic time. Research by the Building Engineering Services Association (BESA) in 2022 found that opening a window to let in fresh air could be counterproductive in many cases, and actually worsen indoor air quality. 

The study found that 76% of people living within a mile of an A-road believed that the air near their home was 'very clean' or 'fairly clean', along with 74% of those living within a mile of a train station, 73% of people living close to a motorway and 70% of those living close to an industrial plant. 

But, according to the BESA, these locations 'create millions of tonnes of highly damaging air particles which enter our bodies and can remain for up to three months'.

If you suffer from hay fever, don't open your windows in the morning, when the pollen count is highest. The BESA recommends monitoring your local pollution levels, keeping windows open for longer on days when pollution levels are lower and for less time when pollution levels are higher.

DEFRA (the Department for Environment, Food and Rural Affairs) has an interactive pollution forecast map.

2. Use your cooker hood and extractor fans

Cooking produces grease, smoke, smells and moisture. Switch on your cooker hood and fans during and after cooking – even if you find them annoyingly noisy – to clear the air of oil and other ingredients that have evaporated. This will also limit damage to your walls and kitchen cabinets.

If you can, get an extracting cooker hood, sometimes called a vented hood or ducted hood, rather than a recirculating one. Extracting hoods send the air out of your home through the wall or roof, while recirculating models filter the air through a carbon filter and recirculate it inside your kitchen. If you have a recirculating hood, make sure you clean and change the filter regularly.

You could also install an extractor fan in any room where you want to control humidity, gas or smoke. An extractor fan in your bathroom can pull moist air out of the room, preventing mould spores growing. It can also remove the after effects of using toiletries and cleaning products.

We test all the cooker hoods we review in extraction mode, which is a more effective way to remove steam and smells. See our cooker hood reviews to find the best one for you

3. Don't block existing ventilation

Avoid blocking existing permanent ventilation features, such as air bricks and trickle vents on windows. They allow air to circulate naturally when windows and doors are closed, as well as allowing oxygen in, moderating internal temperatures, reducing the risk of condensation and preventing pollutants building up inside.

In 2017, we carried out an investigation into indoor air pollution in three houses: one from the Victorian era, one from the 1950s and one new build. We performed a range of everyday tasks in the houses – vacuuming, cleaning, using air fresheners and candles, cooking a fry-up and burning toast – and measured the air quality in each house before and afterwards.

We found that the highest levels of air pollution were in the 1950s house, where home improvements such as cavity wall and roof insulation, double glazing and other energy-efficiency measures had made the house overly airtight.

4. Vacuum frequently

Make sure you vacuum often to remove polluting particles. The best vacuum cleaners will pick up twice as much dust as the worst, and they’re much better at stopping particles leaking back out into your room.

Carpets can harbour allergens, so it's important to vacuum these often, especially if you're in a rental property. If you suffer from allergies, and have the option to, it's a good idea to replace your carpets with solid flooring, which will be much easier to clean.

It's particularly important to vacuum if you have pets, as pet dander can add to the air pollution in your home. Dogs and cats naturally shed old hair – some twice a year, some all the time. Pollen can also attach itself to your pet's fur and be carried indoors, which isn't ideal if you're a hay fever sufferer, so keep your pet off your bed if you can.

Consider the following when choosing a vacuum cleaner:  

• Cylinder or upright – Cylinder models are useful for stairs and hard-to-reach places, but many struggle with pet hair. Uprights cover large areas of floor more easily, but the brush bar in the floor head can get tangled easily.  
• Cordless or corded – A cordless vacuum might make quick clear-ups easier, especially if you opt for one that converts into a handheld vac. However, their smaller dust capacity will mean more frequent bin emptying and filter cleaning. 
• Bagged or bagless – Bagged vacuum cleaners can protect you from contact with allergens, although you’ll have the ongoing cost of replacement bags. If you go for a bagless model, empty it outside if you can, and use gloves and a mask if you have serious allergies.
• Extra tools – Some vacs come with extra nozzles and tools, which can be good for pet hair. Mini turbo tools with a rotating brush bar can help by picking up fluff in places where you can’t use the main floor head, such as sofas or stairs.

Read our guide on how to vacuum your home effectively. If you're shopping for a Best Buy, browse our vacuum cleaner reviews

5. Reduce dust in your home

However often you clean, you'll never get your house free of dust, but you can reduce it. Don't wear shoes indoors, wash bedding regularly and take non-washable items outside to shake clean.

NICE (the National Institute for Health and Care Excellence) says you should avoid buying a second-hand mattress if you're allergic to dust mites.

6. Be on the lookout for damp and mould

High humidity levels can cause respiratory problems and provide a perfect breeding ground for mould spores, dust mites, clothes moths, fleas, cockroaches and other nasties. 

If you've got asthma or a weakened immune system, you should take particular care to keep humidity levels in your home in check. According to the charity Asthma UK, 42% of asthmatics surveyed said that mould and fungi triggered their asthma.

To tackle damp and mould, try the following:

• Avoid hanging wet washing indoors. You might not have any other option if you don’t have a tumble dryer or an outdoor clothes line, but when moisture in the air meets cold surfaces, such as windows and walls, it condenses.
• If you must dry your washing indoors, open a window so water vapour can escape. Alternatively, use a dehumidifier and close the windows and doors of that room.
• Use a clothes airer rather than hanging your washing directly on the radiator. Putting clothes on the radiator can cause condensation, add to your heating bills, damage the delicate fibres in your clothes and complicate your case if you're renting and trying to get your landlord to do something about your damp problem.
• Set up your clothes horse in the sunniest spot in your home, unless that’s your bedroom, as you should avoid drying clothes in the room you sleep in.
• Don’t put damp clothes back in your wardrobe. Getting mould out of a wardrobe can be a nightmare – you can’t just set to it with mould remover and a stiff-bristled brush, because this could damage the materials.

A dehumidifier can help to keep your home's humidity levels in check and prevent mould developing – head to our dehumidifier reviews to find out more

7. Ventilate when cleaning and decorating

When painting, decorating and cleaning, make sure that the room is well ventilated. Chemicals found in everyday products, such as paints, aerosols and cleaning products with limonene and pinene (familiar lemon and pine smells), can emit VOCs. 

Exposure to very high levels of VOCs can cause eye, nose and throat irritation, as well as headaches and nausea. In the long term, they can also cause damage to the liver, kidneys and central nervous system.

If you've got asthma, look for paint that is labelled 'low in VOCs' to minimise your exposure. After decorating, wait for paint and solvent smells to subside before using the room again.

Reduce your use of easily inhaled sprays, aerosols and furniture polish (dust with a damp cloth or electrostatically charged duster instead). Scented candles and air fresheners can also be a culprit for airborne irritants; if there's an unpleasant odour in your house, track down and deal with the source rather than trying to drown it out.

NICE says that women who are pregnant, and babies under 12 months, at are increased risk from exposure to poor indoor air quality. It also says that pregnant women, new mothers and people who live with them 'should reduce their use of household sprays, air fresheners and other aerosols and always follow product instructions', 'avoid activities that produce particulate matter such as using candles' and 'always keep the room well ventilated during these activities'.

8. Use less-polluting cleaning products

Consider switching to ways of cleaning that are less polluting than household aerosols and sprays.

• E-cloths are microfibre cloths designed to remove more than 99% of bacteria. All you need to do is rinse the cloth and wring it out, draw it across your dirty surfaces and wash it afterwards with hot water or in the washing machine. 
• White vinegar can be great for some jobs, such as descaling kettles and shower heads, and leaving streak-free windows. Don't use vinegar to clean mirrors, stone or granite kitchen countertops, or wooden or stone flooring, as it can make them lose their shine. Don't use it for knives, washing machines or dishwashers, either, as it might cause damage. 
• Baking soda works wonders for stains and smells, it's non-abrasive and saves you having to scrub or use bleach. You can use it to wipe away old food residues from the inside of a fridge, for example, or you can add it to pots and pans to help lift stubborn, crusty foods.

Be aware that in marketing, words such as 'green', 'natural' and 'eco friendly' are often meaningless, as there's no regulation around their use.

If using shop-bought cleaning products, choose cream cleaners over spray cleaners, and scentless or low-scent products if you can. The less fragrance, the less reactive chemistry there is likely to be.

9. Don't use unvented heaters

Avoid using unvented (also known as vent-free) appliances such as freestanding gas and paraffin heaters. These might sound convenient, as they don't require a vent pipe or chimney, making them easy to install, but they release a number of harmful pollutants into your room. 

All gas heaters, even when burning properly, produce carbon dioxide (CO2). When carbon dioxide builds up, it results in drowsiness, dizziness and headaches, creating an impression of a stuffy, closed house.

10. Be aware of the risks of wood-burning stoves

You might rely on a wood-burning stove for heating. However, if you've got asthma, or a condition that puts you at greater risk from indoor air pollution, think carefully before using one. Both Asthma UK and the British Lung Foundation recommend avoiding them.

A 2020 study by researchers at the University of Sheffield and the University of Nottingham found that residential stoves released high intensities of PM2.5 and PM1 – particulate matter already identified by the World Health Organisation (WHO) as a very serious health risk, able to penetrate your lungs and enter your blood stream. Researchers installed air-quality monitors in the homes of people with log burners and measured the level of harmful particulate matter over a four-week period.

If you already have a wood-burning stove or fire, you should burn only untreated, fully dried wood with a moisture content of 20% or less. This will be labelled as 'ready to burn'. Some types of fuel, such as wet logs and house coal, produce far more particulate matter than dry logs and low-sulphur smokeless fuels, such as anthracite coal. 

When wood doesn't have a good enough supply of oxygen, it creates more smoke and potentially harmful emissions. It also increases sooty build-up in your chimney. Make sure the flue damper is open before you use it. Clean the flue and chimney often so that smoke has a means to escape.

Keep the fire constant, so that the flue stays at the right temperature. This will help to avoid carbon monoxide (CO) coming down the chimney.

Although new Ecodesign regulations came into force in January 2022, many scientists remain extremely concerned about the impact even of the new wood-burning stoves on our indoor air quality.

For advice on how to use your wood-burning stove in a less polluting way, read wood-burning stoves: pollution and health impacts

11. Don't smoke indoors

You don't need us to tell you about the dangers of smoking. You might be surprised to learn, though, that when you smoke, more smoke gets released into the air – where others can breathe it in – than goes into your lungs. 

The NHS says that second-hand smoke (the smoke you exhale, plus the sidestream of smoke from your cigarette end) puts your family at risk from the same diseases as smokers, such as lung cancer and heart disease. Children living in a smoky house also have a greater chance of developing asthma, breathing problems and other allergies.

Smoke can linger in the air for hours after you've finished smoking, and it can spread from room to room. Opening a window or door won't banish the smoke, as it can blow back inside and stick to surfaces such as soft furnishings to be released later, sometimes in more harmful forms (third-hand smoking). If you're going to smoke, go outside, close the door behind you and move away from the house.

12. Consider an air purifier

Buying an air purifier shouldn't be the first or only thing you do to reduce your indoor air pollution: first, deal with the problem at its source by minimising any pollution you're creating.

But, as well as taking the above steps, you could consider an air purifier. This could be particularly useful if you have allergies or respiratory problems, live near a major road or industrial facility, or you're often exposed to second-hand smoke or odours you have no control over.

Air purifiers aren't perfect as they don't offer a solution to the problem of air pollution. But they can reduce the level of pollution you breathe in. However, they'll only be able to clean the air in one room rather than your whole house.

• Choose one with a HEPA filter if you want to remove particles such as dust, pet dander and smoke particles from the air. Filters with names such as 'HEPA-type' aren't held to the same standards of filtration efficiency. 
• Look for one that comes with an activated carbon filter if you need to remove smells or gaseous pollutants. A HEPA filter won't filter out these smells as they only remove particles. 
• Close the doors and windows in the room where the air purifier is so you're not letting in more pollution for it to tackle.

We test each air purifier with a range of particles and gas pollutants, so we can tell you which do the best job of removing these pollutants. Discover the best air purifiers.

Air pollution in a rented property

If you're renting, you're going to have less control over the indoor air quality in your home than if you own it. 

Contact your landlord if:

• ventilation is inadequate (for example if trickle vents, extractor fans or cooker hoods are damaged)
• repairs are needed to stop water entering the building
• heating and insulation improvements are needed to prevent condensation.

If your landlord is uncooperative and refuses to take action, contact your local council. In March 2019, a new law came into force to make sure rented houses and flats are 'fit for human habitation'. In other words, they must be safe from things that could cause you serious harm.

Depending on your tenancy agreement, if the property you're renting falls short of this, you can take your landlord to court (the Homes Act). 

Even if your tenancy agreement means you don't have recourse to the Homes Act, you should still contact your local council if you're worried about conditions in your home, as it can take action on your behalf.

If you're dealing with an issue related to your rented property, see our guide on how to claim against your landlord for disrepair