Indoor Air Quality FAQs

Read some of the frequently asked questions and answers relating to indoor air quality.

 Where can I buy a carbon monoxide alarm and where is the best place to fix it?While alarms are very useful, it is equally important to spot potential sources of carbon monoxide and have them checked or removed. Carbon monoxide is more of a risk with some older gas appliances, solid fuel burning and paraffin/oil heaters.

Gas appliances should be serviced annually by a Gas Safe registered engineer. Any signs of defects, soot or other staining, fluctuating yellow pilot lights (or excessively noisy boilers) should be inspected by a (Gas Safe) engineer.

The flues to open hearths and solid fuel burners should be swept once a year and checked for damage allowing leakage of fumes.

Never use charcoal indoors. Chimney sweeps can be contacted at National Association of Chimney Sweeps (NACS)

Paraffin heaters should be checked constantly for blue not yellow flame. But these are not recommended because they are a potential fire hazard and can cause excessive condensation and damp problems.

Any room with a gas or fuel burning appliance must be properly ventilated. It is vital when draught proofing not to block ventilators or airbricks.

For extra security carbon monoxide detector alarms can be fitted, and as a minimum should conform to BSEN 50291 (look for the Kitemark).  Generally the alarm should be fitted in a high position in the room. Proper fitting instructions should come with the device, but otherwise advice can be obtained from the HSE or local fire brigade.

 How do I know if I am suffering from carbon monoxide poisoning? Permanent ventilation in each of the rooms with a gas appliance is vital, and equally important you should be getting those fittings serviced regularly by a CORGI registered service engineer. If the gas fittings are as old as you suggest it’s likely that one, or more of them, will need replacing to conform to modern safety standards. 

If you have been feeling drowsy or dizzy, or often suffer from headaches and feelings of nausea these can be signs that you are being exposed to carbon monoxide. But these symptoms can indicate other health problems so it is important to see your GP.

 Can I use a disposal BBQ on the hob in my kitchen? There could be a very serious risk of carbon monoxide poisoning which can be deadly. We would strongly advise against charcoal barbecues indoors.  In fact technically it is an offence to burn charcoal inside your house anyway, because the whole borough is a smoke control area in which only (authorised) smokeless coal can be burnt.

The health risk with charcoal burning in confined spaces like a kitchen is that charcoal generates large amounts of carbon monoxide. Outdoors this is not usually a problem because the fumes disperse easily and there is plenty of oxygen to convert carbon monoxide (CO) to carbon dioxide which is virtually harmless in the open air. Indoors the burning charcoal readily consumes the available oxygen and carbon monoxide builds up.

Even mechanical extract ventilation may not be enough to remove the carbon monoxide fumes. But the risk of CO poisoning increases rapidly when the extract ventilation is turned off – say when cooking has finished, or at the end of the evening. The burning embers may appear harmless but they still give off CO. There have been several cases when people in rooms above charcoal grills have died from CO poisoning, or become seriously ill.

Please consider using the ordinary cooker grill for indoor use and keep the barbecues for outdoors.

 My new carpets has an intolerable smell and is giving me a headache. Someone told me that the fitters spray the carpets to discourage cat fleas and other insects.  Can I call the fitters back to counteract the spray with a neutraliser? It is most unlikely that the carpet has been treated with pesticide, unless the supplier has specifically undertaken to do this, because pesticide chemicals are likely to damage the carpeting materials. However modern carpet manufacture usually entails synthetic piles secured with solvent based adhesives which are volatile and still give off fumes for a short time after the carpet is unrolled and laid.  Spraying more chemicals in the form of de-odourisers is only likely to add to the problem.

Some people are particularly sensitive to these volatile substances (4-PCH, styrene and butadiene among others) and are advised to leave as many windows open as possible without compromising security. Ideally vacating the flat for 48 to 72 hours should give sufficient relief from the initial concentration of gases. The smell does not usually persist longer than about three weeks.

 Two weeks ago I moved into a brand new basement flat with carpeting and furnishings all supplied and fitted. After two days I thought I had ‘flu and I went to my GP a week later because I still felt ill. My doctor suggested I ought to find out if my home had been built on a contaminated site. I’ve found out that my flat was built on industrial land. Should I ask my housing association to move me somewhere else? There are very few ex-industrial sites in the borough and an even smaller number where past contamination even untreated could cause such immediate distress.  In all recent cases the Council’s Environmental Quality Team which investigates previously contaminated land will have insisted on proper remediation through the Planning process, with venting of possible ground gases in exceptional cases.

In fact almost all redevelopment in central London includes a basement level, which inevitably means a deep excavation with the original soils and other materials removed and transported out of the borough, to special disposal sites if it is found to be contaminated.

It is much more likely that the combined “off-gassing” or fumes from the new materials and fabrics used in fitting out and fully furnishing your flat have affected you in a way that provokes similar symptoms to a bout of ‘flu'. Ideally vacating the flat for 48 to 72 hours should give sufficient relief from the initial concentration of gases.  Otherwise we would advise you to leave as many windows open as possible without compromising security. 

Although you may be very conscious of the smell it should subside within three to four weeks. If you are particularly sensitive to volatile substances indoors you may want to avoid the use of aerosols for cleaning or air fresheners, and if you burn scented candles for fragrance you may decide to do without these as well. In fact paraffin wax candles can give off more particulate pollution than cigarette smoking.

 The corners of my son’s bedroom are darkening with patches of mould growth and it smells damp. We have scrubbed off the dark patches before and re-painted the room, but it hasn’t solved the problem. Is it okay to ignore this or can more be done?   Mould growth is not only unsightly but unhealthy. Mould tends to spread and produces spores which aggravate conditions such as asthma. Cold and damp conditions may also predispose people to chest infections like colds and even bronchitis.

As you have found, redecorating by itself doesn’t help much, although paints with biocidal additives may slow down any re-growth. Adequate heating and ventilation are needed to prevent condensation forming in corners and stagnant parts of the room, and on interior surfaces of poorly insulated external walls.  You should try and avoid leaving damp clothing and towels in the room.  There may also be other causes of damp such as a slow leak from a radiator, or damp penetrating from an external defect like leaking guttering, or down pipes. Technical advice on eliminating the factors that cause mould growth is available from our Housing Department on 020 7361 3002.

 I have just given up smoking, but my partner smokes more than 20- a-day. I notice cigarette smoke much more now and I’m worried about how much our two kids are breathing it in. I keep opening windows when my partner lights up – does this help? Obviously just you kicking the habit will mean your kids are breathing in a lot less smoke, but if you could persuade your partner to smoke in one room (that the kids don’t use much) that would cut down the smoke they breathe even more). Perhaps for some of the time your partner might be willing to smoke outside. Opening the window of a room with smoke does help to ventilate the fumes, but carcinogens and toxins stay in the air and cling to furnishings. 

If you have a car, making that a smoke-free “zone” is a big step towards reducing the risks your kids face from passive smoking.

Quitting smoking means you probably don’t need any more advice about the major health benefits of being smoke free, and if your partner has thought about quitting you may be able to point her/him towards a source of professional advice.  The NHS Kensington and Chelsea Stop can be contacted on: 0800 085 9147. 

 I suffer from itchy eyes and irritating coughs almost all the time. My boss said “it’s what you get from travelling on London underground”. Last year I was temporarily relocated to a small building with no air conditioning; they just opened the windows when needed. Even though I was used to cooler conditions, my eyes stopped itching and I breathed more easily. What can I do about my office now that I’m back? Full air conditioning (i.e. with both temperature and humidity control) in good working order and properly adjusted should make working conditions much more comfortable. However if the settings result in an over dry environment this can cause sore or itching eyes and a dry throat. Just as important is regular cleaning, or replacement of the system’s filters, and cleaning of the ducting and vents that circulate the internal air. The air itself should be constantly refreshed at a rate of 10% per cycle.  

Sometimes air conditioning is blamed for complaints even though the actual cause lies elsewhere, typically in poor office cleaning routines. Un-cleaned carpeting harbours not only grime but also dirt, bacteria from food debris, dust mites, mould spores and other biological contaminants from soiling. Apart from daily vacuum cleaning, ideally carpeting should be steam cleaned once a year to keep these potentially harmful agents at a low level.

Health and safety in most offices is enforced by the local authority, our inspectors can be contacted for advice on 020 7361 3002. Depending on the initial assessment an inspection may be arranged to investigate the problem. Your organisation’s health and safety representative, or union official, may also be able to help. Further information can be obtained from the Health and Safety Executive.

 We have two very young children and we live next to a main road. I don’t want them living with the high levels of pollution that are regularly reported for this part of London. Is there anywhere in the borough we can move to that has less pollution? Concentrations of the two key pollutants nitrogen dioxide (NO2) and fine particles (PM10) tend to be slightly lower in the north of the borough, although there is little difference next to roads. You would have to move to the suburbs and away from main roads to experience an appreciable difference.

However there are quite a few things you can do to lower internal levels of the two pollutants as well as volatile organic compounds which also pose a health risk. The following seven steps are useful to know about, if you haven’t taken them already: ​

 - If possible ventilate your home on the side away from the road.
 - When your children are ready for school, walk them there rather than using the car – car interiors concentrate street pollution.
 - If you use gas for cooking, install mechanical ventilation e.g. an extractor hood over your kitchen cooker, and make sure it’s switched on whenever the burners are lit.  Otherwise open the kitchen window because gas cooking generates significant levels of NO2.
 - If you are a smoker, restrict smoking to one room not used by the children, or smoke outside.
 - Wherever possible avoid aerosol sprays for cosmetics, cleaning materials, paints and varnishes, and keep containers of vapour forming solids or liquids sealed.
 - Substitute “ecological” products when available.
 - Avoid using air fresheners.  

 We recently had a dining table restored with several coats of varnish; the fumes were strong and lingered. The next day my brother, who was staying with us had a bad headache and became violently sick. Is he just one of the unlucky ones who is sensitive to solvents, or are they dangerous? Your brother may well be sensitised to certain solvents and hopefully has received medical advice on how to cope with, or avoid the effects. However there are a number of solvents with volatile fumes that should only be used in very well ventilated spaces, preferably in the open air. If the fumes remain noticeable windows should be opened wide especially in bedrooms at night.

The manufacturers strongly recommend avoiding more than the absolute minimum exposure and prolonged exposure to solvent fumes is likely to be a health risk especially some solvents like Trichloroethylene TCE and Perchloroethylene PERC. TCE is used in paints, glues, carpet cleaners and degreasers and PERC is also found in a number of household products.  Both are potential carcinogens and have now been linked to Parkinson’s disease.

Wherever possible water based products should be used in preference to other solvents, for example varnishes and paints can be obtained with a water base.

 My daughter has picked up an asthmatic wheeze since starting school. The head teacher has now told me three others children are also suffering, so they have removed the pet rabbit from the classroom and stopped using aerosol polishes for cleaning desks. Our GP advised us to list any possible sources of allergenic irritants at home and I’m wondering what to do about our cat? You will obviously need further medical help in trying to identify the cause or causes of your daughter’s asthma if it persists. However pet dander (fur, and other animal debris) dust mites, fungal and mould spores are all known to cause allergenic reactions in sensitised individuals. It may be worthwhile considering steam cleaning the carpets and vacuum cleaning furniture to reduce dust mites and not allowing the cat in your daughter’s bedroom (if this happens at the moment).

The process of elimination, which your GP has initiated, may lead on to looking at aerosol products you use and whether anyone in the family is a smoker. Unfortunately the causes of asthma are not fully understood, but precautionary measures may reduce the symptoms.

The Council has produced a leaflet which highlights some of the factors that can lead to poor air quality in the home, as well as advice on ways to improve it. If you would like a printed copy of the leaflet, please email us at

Indoor Air Quality leaflet [PDF file] (file size 818Kb)