/ Health, Home & Energy

Is your home making you sick?

indoor pollution cleaning spray

Talk about air pollution, and it’s likely you’ll think of car emissions and polluted streets. But we spend 90% of our lives indoors, and the odourless and unseen gases, chemicals and small particles in the air, could literally make you sick.

Worse still, the products you’re using to mask the bad stuff – the lemon and pine you associate with cleaning products – could actually be the bad stuff.

Some people are more susceptible to the effects of indoor pollutants too – for example, if you suffer from asthma, are sensitive to allergens indoors or have heart and lung disease.

Looking for air purifiers? We’ve tested 10 models to see how well they remove pollen, dust and smoke from the atmosphere. 

Indoor pollution put to the test

So, where’s the evidence of indoor pollution? We sent lab technicians to three ordinary semis: a supposedly ‘draughty’ Victorian one; a 1950s house made airtight with improvements such as double glazing and cavity wall insulation; and a new-build.

We wanted to see how much pollution was generated before and after bursts of common activities in kitchens, bathrooms, living-rooms and bedrooms. For example, when we vacuumed, did the cleaning, used air-fresheners and scented candles, cooked a fry-up and burned the toast.

We discovered surprisingly high levels of pollutants with potential long-term health effects in all the test houses.

For example, we found very high levels of volatile organic compounds (or VOCs) in every room we tested. Results were as much as 34 times the UK Building Regulations recommended maximum level – although measured over a busy 30 minutes, not 24 hours.

This was after activities including burning candles and using plug-in air fresheners, scented washing powder and toiletries such as antiperspirant and perfume.

What are VOCs?

VOCs are chemicals found in a wide variety of materials in the home and from outdoors, that can evaporate into the air at room temperature, producing vapours that we inhale.

VOCs (especially terpenes including limonene and pinene) can combine with ozone from outside air, particularly during hot weather, to form gases including formaldehyde. This is a breathing irritant that can cause sensitisation reactions, and – at very high levels – is carcinogenic.

We also saw very high increases in particulate matter – tiny particles that can enter your lungs, potentially causing serious health problems over time – in all our test-house kitchens.

How you can breathe easy

So what does this mean for you? Well, this shouldn’t make you anxious about every scented candle you burn, or open fire you light. This is about the longer-term view.

In workplaces, employers are required to provide ventilation for adequate fresh air. Inside our own homes however, the quality of the air is in our own hands, and it’s all about controlling sources of pollution and maximising ventilation.

Choose products and activities that will minimise pollution in the first place, ventilate before and after polluting activities such as cooking, vacuuming and using toiletries. Keep trickle vents open, use extractor fans and don’t block air bricks.

Are you concerned about indoor air pollution? What do you do to keep your home ventilated?


I find that products that have a vanilla scent give me an instant headache and make me feel really nauseous. I’ve given away quite a few scented candles because of the reaction I have when/if I burn them.


Funnily enough the strong smell of vanilla does the same to me Melanie .


My advice is to avoid buying household products sold as sprays or aerosols.

I am an asthmatic and some scented products can leave me short of breath. When staying away from home my first job is to round up reed diffusers, plug-in air fresheners and even bowls of fresh potpourri. I consign them to the back of a cupboard, out of harms way.

At home, I keep the trickle vents above my windows open and the house has a chimney, which helps provide ventilation. I usually use the cooker extractor hood when cooking and always when frying.

Thanks for this Conversation, Joanna. Is there any more information about the VOCs discovered in the Which? tests done on properties?


Early double glazing installations rarely had trickle vents and they are still regarded as an optional feature rather than the default provision. I think they are essential to maintain a cross-flow of air in a home even in cold weather. They don’t all have to be open but it is good to have at least one open on each floor on each side of the house that has a window. Keeping internal doors open helps cross-ventilation. Modern enclosed bathrooms and en suite shower rooms don’t help because the extractor fans never pull out enough air to remove the particles quickly and freshen the atmosphere, and bathrooms are probably the worst rooms for using pollutants for a variety of purposes.

Only in the last decade or so have double-glazed casement windows had two-position locking latches so that a small ventilation gap can be left open. Not a good idea to leave them in that position on the ground floor when the house is vacant or overnight because the window can be prised open, but on upper floors they can be left like that while residents are in bed; they are also good in children’s rooms because the window is effectively locked ajar and cannot be opened any wider.

Even in the winter when the central heating is on all day it is a good idea to open a window or a garden door from time to time just to change the air and make the house smell fresh; it doesn’t have to be for long.

I am not sure that we should live in a totally sterile environment, and all food preparation and cooking releases some ‘pollution’, but as a society I think we have become too heavily influenced by hygiene marketing and have an array of sprays, gels, carpet powders, plug-ins and other things that just add to the toxic overload and all competing with each other to achieve an unnatural fragrance that a good blast of fresh air will supply for nothing [unless you live near a soap factory or a die works or in Bury St Edmunds which has a massive beet-sugar factory in the middle of the town that covers the entire district with a sickly atmosphere – not harmful though, I understand, just too much of a good thing].


Hairspray is another product that can have an adverse affect on some people and historically it has already had two potentially carcinogenic propellant aerosols removed from it (vinyl chloride and methylene chloride) in the last ten years. Specific ingredients are now referred to as fragrances and are not listed on the label so it is not known what has replaced them.

I have now switched the highly perfumed laundry powder I used to use to Waitrose own unperfumed brand for sensitive skins. It certainly does a good job on my cotton white laundry and I am very impressed with the result. I have yet to find a washing up liquid that doesn’t make me sneeze.

My upstairs double glazed casement windows don’t have trickle vents but instead have the two positioned locking latches (John mentions in his comment above,) which are usually kept open in the main bedroom when I am at home. There is more than enough ventilation in my kitchen, which is always tested during the annual boiler service and I also use the extractor fan when cooking. I always open the bathroom window
even in very cold weather after showering and close the door to keep the rest of the house warm.


While effective ventilation is good for healthy living it is even better to stop using products that cause the problems in the first place. The combination of unknown chemicals and hermetically-sealed living arrangements is probably responsible for more health problems than we realise. And it’s not just in our homes – shops, hotels, restaurants, pubs, cinemas, and all sorts of other places are using cleaning sprays, carpet deodorisers, laundry and dry-cleaning chemicals, floor polishes, and other products which get embedded in the fabric and furnishings, suspended in the atmosphere, and recirculated round the air-conditioning system.

I was interested that, in the Which? test, one of the properties used was a Victorian semi. The Victorian builders were the leading developers of the sash window for domestic properties. They had been around for a long time but only in grander places mostly with high ceilings and they were both simple and draughty. The Victorians improved the construction of wooden sash windows which were particularly beneficial alongside the other Victorian introduction – gas lighting. When fully closed and with the sash fastener on the meeting rails tightened, a well-made sash window was virtually draught-proof, but by opening the window by a couple of inches at the top and bottom a flow of air was provided that would remove stale smells [coal fires, candles, and gas lighting among others] and let in outside air [which admittedly was not of the purest in industrial districts]. Cool air would enter at the bottom of the window and hot air would escape from the top opening. The improved ventilation of houses and enforced standards of building separation to admit more air and light were two of the main contributors to public health and the lowering of infant mortality rates. Unfortunately the Victorians were using some fairly gruesome compounds for daily domestic tasks and I was reading recently about the widespread use of arsenic in interior decorations, especially wallpapers, that was never prohibited; the manufacturers just stopped using it when other chemical dyes became available in the latter part of the nineteenth century but arsenic was still in use into the twentieth century. I think we have come a long way since then but we have to be constantly on the look-out for modern chemicals that are being sneakily introduced into our homes, largely on the back of cunning advertising and marketing ploys. The Victorians also came up with carbolic soap [Lifebuoy among others] which had antiseptic properties but could also irritate the skin; this was considered to be virtuous and a sign of its efficacy!


Beryl – I believe the use of vinyl chloride as a propellant in hairspray etc was banned in the 1970s, and not before time.

Methylene chloride (dichloromethane) is a solvent rather than a propellant and I’m not sure when this disappeared from household products. In recent years it has been removed from paint and varnish removers, though it is still available online.

As you say, ‘fragrances’ are not identified, and that must change.


I stand corrected I should have written “ingredients are not always listed”. Having just checked the list of ingredients on my aerosol can of hairspray they read as follows:

Alcohol, Denat, Dimethyl Ether, Aqua/water, Polyurethane, Dimethicone, Glycerin, Hydroxycitronellal, Limonene, Alpha-Isomethyl, Ionone, Argania Spinosa oil/Argania Spinosa Kernel Oil, Coumarin, Linalool, Citronellol, Benzl Alcohol, Geraniol, Benzyl Benzoate, Amyl Cinnamal, Parfumerie/Fragrance, (F.I.L C170584/1).

Apart from the obvious highly inflammable, can anyone translate into which ingredients are potentially harmful/unharmful?