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Indoor air pollution

Causes and effects of indoor air pollution

Indoor air pollution can be caused by many things. On this page, we explore the most common causes of indoor air pollution, the effects on our lungs and how to avoid them. 

Poor indoor air quality can be caused by: 

If you’re affected by poor indoor air quality, find out our top tips for improving indoor air pollution.

How does heating and cooking affect indoor air quality? 

Cookers, heaters, stoves and open fires can release pollutants into your home. High levels of exposure to these pollutants can lead to lung and heart disease.  

Burning wood and coal 

Burning wood and coal in a stove or on an open fire released particulate matter (PM). This can irritate your nose and throat, giving you a cough or breathing problems. 

Burning wood and coal also adds to outdoor air pollution.  Pollutants from burning wood on stoves and open fires create a higher percentage of emissions than road traffic emissions. Where possible, you should avoid using wood burners, especially if you have a lung condition. 

If you have asthma, your symptoms might get worse. If you have COPD, it makes you more likely to have a flare-up. In the long term, your risk of getting lung cancer is also increased from burning coal or wood. 

Heating and cooking with gas releases tiny particles of nitrogen dioxide (NO2) and carbon monoxide (CO) into the air you breathe. However, gas is much cleaner to burn than coal and wood.  Coal burning produces 125 times more sulphur dioxide than gas, on average. If you use a gas cooker, the most important thing is to keep the room ventilated when cooking by using an extraction fan and opening windows.

Electric is seen as the cleanest form of heating and cooking, as it releases less particles than gas, and much less than burning wood and coal. You may want to consider switching to electric cooking if possible - especially if you have a flare-up of your symptoms from breathing in gas, wood or coal particles. 

Remember to have all your gas appliances such as boilers, cookers and fires checked annually. The Royal Society for the Prevention of Accidents (RoSPA) has more information about gas safety. 

Carbon monoxide

The most dangerous pollutant is carbon monoxide, which can kill you within a few hours.  Carbon monoxide is a poisonous gas with no smell or taste. It’s created when fuels like gas, oil, coal or wood don’t burn fully. It’s important to make sure cooking and heating appliances are serviced regularly, and that vents and chimneys are not blocked. An appliance that isn’t working properly may release more soot. It’s recommended you have a carbon monoxide alarm in every room where fuel is burned. Take a look at this useful page from Which? on how to choose a carbon monoxide alarm.

If you have mild carbon monoxide poisoning, the first symptom you might notice is a headache. You might also notice flu-like symptoms, but without the temperature. 

If several people in one building develop flu-like symptoms without a temperature, then it could be due to a carbon monoxide leak – so act immediately.  Switch off all gas appliances and ventilate the property. Call the gas emergency number 0800 111 999 or the Health and Safety Executive Gas Safety Advice Line on 0800 300 363.

How can damp and mould affect me? 

In Britain, a lot of houses are old, and the weather can be wet and cold. So, it’s important to stop our homes getting damp and mould growing.  Find out more about preventing damp and mould.

Damp leads to condensation, which encourages mould and other fungi to grow.  Lots of things can cause this, from cooking, to washing and drying clothes. Condensation is more likely to happen in cold places in your household, like windows or rooms with external walls. 

If your home’s damp, you might have an irritated nose and throat, or feel short of breath. If you have a lung condition, your symptoms may get worse. It’s common to have an allergy to mould.  

One fungus often found indoors is called aspergillus.  It grows on dust and powdery food items like flour. It can cause a wide range of conditions, from mild irritation of your airways to more serious infections if you have a lung condition.  

If you have bad damp, mould or fungi, get professional help to deal with it – especially if you think it might trigger your breathing problems.  If you are renting, you should tell your landlord about the problem and they should arrange to fix the underlying cause. Shelter and citizens advice both have advice on dealing with damp and mould in a rented home.  You could also ask your GP for a letter to support further action. 

How can smoke and vapour affect me? 

If you have a lung condition, you may find that breathing in tobacco, cannabis, and e-cigarette smoke causes your symptoms to flare-up. You might also have the same symptoms when burning candles and incense. 

What are the effects of cigarette smoke? 

Smoking is the main cause of preventable illness and death. Second-hand tobacco smoke is also bad for our health.  The good news is that laws have banned smoking in enclosed public spaces, including public transport, workplaces, and in cars with children.  

If anyone smokes in your home, tiny particles from tobacco smoke can drift all through your house. These particles can remain at harmful levels for up to five hours.  Breathing in this smoke may cause your nose or throat to get irritated, and you might cough or have trouble breathing. 

If you have a long-term lung condition smoking will make your symptoms worse. In the long term, your risk of getting lung cancer is also increased.  

Children are particularly at risk. Breathing in tobacco smoke affects how their lungs work and make them more likely to develop a long-term lung condition when they grow up. 

Using e-cigarettes is less harmful than tobacco smoking, but these devices are not completely harmless. If you decide to use an e-cigarette at home, it should be kept out of reach of children. If you are a parent or carer you should consider the drawbacks of permitting vaping in the home. 

Some people are affected by second-hand smoke from cannabis cigarettes. If you have a long-term lung condition such as asthma, breathing this in can make your symptoms worse.  

Smoking in cars with children campaign

What are the effects of burning candles and incense?

Light candles in well ventilated, large spaces instead of smaller spaces like bathrooms. 

Candles and incense sticks emit particles and other pollutants when they burn. Incense sticks emit more than 100 times the amount of fine particles as candles. There is also evidence linking incense burning to lung disease, so try and avoid using these regularly.   

Candles are much less of a health risk - but some fragranced candles may contain VOCs.  Try using an extractor or opening windows while burning candles if possible.  

How can chemicals in cleaning and decorating products affect me? 

The products we use to clean and decorate our homes can sometimes contain chemicals called volatile organic compounds (VOCs). It’s a good idea to avoid breathing in VOCs, as well as products that contain bleach or ammonia. 

Products containing VOCs, particularly those in a spray, can cause irritation to your lungs and may increase your risks of developing an allergy or asthma.  If you live with a lung condition, your airways are likely to be irritated. VOCs are not always clearly labelled on cleaning products, so it’s best to look for chemical free or allergy friendly products. 

VOCs can be found in products such as: 

  • washing detergents 
  • furniture polish
  • air fresheners 
  • deodorants and perfumes
  • carpet cleaners
  • pesticides and fungicides
  • paints and paint strippers
  • varnishes and glues.

Some decorating products have a ‘globe’ symbol on the packaging to tell you what level of VOC is in the product.  

VOC labels

(Image from the British Coatings Federation, 

You may find other types of VOC, such as formaldehyde, in carpets, furniture, shelving and flooring.  Some people say the smell of a new sofa or soft furnishing sets off their allergies or makes their asthma worse.  Products containing formaldehyde should be clearly labelled according to Health and Safety Executive (HSE).  

What building materials cause indoor air pollution? 

If you have a lung condition, you may find certain building materials trigger your condition. Building materials such as asbestos pose a risk to your lung health. 

The Alliance for Sustainable Building Products has suggestions for safe, environmentally-friendly building products. 


Asbestos poses many risks to lung health. It has been banned in the UK since 1999, but older properties may still have asbestos-containing materials.  

Before its dangers were known, asbestos was often used in buildings for insulation, flooring and roofing, and sprayed on ceilings and walls. Breathing in asbestos fibres can lead to lung diseases such as asbestosis and mesothelioma.

If you find asbestos in your home, make sure it remains undisturbed. If it’s damaged or deteriorating, get it removed by accredited professionals. We have more detailed information on what to do if you think you’ve been exposed to asbestos.


Fibreglass is a type of building insulation. Like asbestos, if disturbed it becomes part of the dust in the air and can be easily breathed in. Fibreglass is safer than asbestos, but it still comes with risks if you breathe it in. It can irritate the airways, and if you live with a lung condition and breathe it in, you may see your symptoms get worse.  

If you have fibreglass in your home, don’t disturb it. If you come into contact with it, wear a mask and protective clothing.  


Volatile organic compounds (VOCs) in building materials may include roofing and flooring materials, insulation, cement, coating materials, heating equipment, soundproofing, plastics, glue and plywood. Find out more about how VOCs could affect you.


Radon is a natural radioactive gas that comes from rocks and soil in granite areas. It’s colourless and odourless.  Certain areas of the UK have higher levels of radon. The radon level in the air we breathe outside is very low, but it can be higher inside poorly ventilated buildings. 

High levels of exposure for long periods of time may put you at risk of developing lung cancer.  

If your home is built on ground with a higher level of radon, you can take measures to reduce it. You can find out if your home is in a radon-affected area at UKradon.

Indoor radon often varies from building to building. If your home is affected, UKradon has a tool to help you decide if you need to reduce the level and how.   

Download our indoor air pollution information (PDF, 504KB)

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