Indoor lamp and curtain

Indoor environment

If you know which indoor triggers make your asthma worse, you can start to avoid them at home.

Know your indoor triggers

Many things that potentially trigger asthma symptoms can be found in your home, including carpets, certain furnishings and cleaning products. You may also come across triggers in other people's houses or in your workplace. But there are steps you can take to reduce the risk of any indoor allergens leading to an asthma attack.


What's the best way to reduce the risk of triggers in the home affecting you?

Whatever's triggering your asthma, the reality is that it's impossible to get rid of all allergens in your home. And if you only get rid of some, it might not make any difference to your asthma. The evidence is clear that when it comes to coping with asthma triggers - including indoor ones - the best thing you can do is stay on top of your asthma. If you manage your asthma well, your body is in a better position to cope when you come into contact with any asthma triggers.

The best ways to manage your asthma are:

  • Take your preventer medication exactly as your doctor has prescribed. It is specially designed to work in the background every day to help reduce your body's reaction to triggers you meet in your daily life.
  • Use your written asthma action plan to help you identify when your asthma needs extra help and what to discuss with your doctor or asthma nurse.
  • Get your asthma reviewed regularly, so you and your GP or asthma nurse can make sure the medicines you're taking are doing the best possible job for you.

Some common triggers in the home

House dust mitesanimals, cockroaches, mould and cigarette smoke are all common asthma triggers in the home. But there are other things found indoors that can also potentially trigger your asthma in different ways. Speak to your GP or asthma nurse about what you can realistically do to reduce your risk of an asthma attack. You can also call the Asthma UK Helpline on 0300 222 5800 and talk to an asthma nurse specialist, Monday to Friday from 9am to 5pm.

Central heating

Some people find that their asthma gets worse when the heating is turned on in the autumn and better when it goes off in the spring. This could be because once the heating is turned on, dust mites multiply very quickly and for some people these are an asthma trigger.

However, "research actually suggests that asthma symptoms are harder to control for people who don't have central heating at home", says Dr Samantha Walker, Executive Director of Research and Policy at Asthma UK. One reason for this is that central heating gives out a dry heat, and asthma is worse in homes that are damp.

Central heating also helps keep a good background level of warmth. This works well for people with asthma who need to avoid sudden changes in temperature (such as going from a heated room into a cold hall) and makes it a better choice of heating than a gas or electric fire just warming one room.

If you're worried you can't afford central heating, read our advice on finances and asthma.

Open fires

Open fires, or wood-burning stoves, can make asthma symptoms worse for some people. Burning wood gives off fine particles and breathing them in can make the airways inflamed. If you have a wood or coal fire make sure any flues are in good condition and working well, and the chimney is swept regularly, so that the smoke can escape.

Whatever kind of heating you're using, be aware of any new asthma symptoms when you first start using it as the weather changes. You might want to book an asthma review with your GP or asthma nurse if you know there is going to be a weather change so you can be prepared. Ask your GP or asthma nurse about increasing your medicines for a time, or keeping your home well ventilated by opening windows. Good ventilation can cut the risk of your asthma being triggered by smoke. It can also reduce the humidity that can result in dust mite levels increasing when the heating goes on.

Carpets and furniture

A chemical called formaldehyde is sometimes used in the manufacture of carpets, furniture, shelving, flooring and bedding. This chemical is a type of volatile organic compound (VOC), which means it becomes a gas at room temperature. Although there's little solid evidence it can trigger asthma symptoms, some people tell us the smell of new carpets and furniture can make their symptoms worse. If you think this applies to you, it makes sense to limit your exposure. Here are some steps that might be helpful:

  • Ask the shop to unroll a new carpet and air it before you bring it home.
  • Buy second-hand furniture instead - after a few years, products stop giving off formaldehyde.
  • Keep rooms well aired when you first bring new furniture or carpets into the home.
  • Consider feather bedding instead of synthetic bedding. Some research has suggested feather bedding is less likely to trigger wheezing. However, some people with asthma find feather bedding can make symptoms worse, so it's a question of finding what suits you.

When you're moving house it's a good idea to check with previous owners if they had a pet. If pets trigger your asthma you might want to get the carpets in your new home professionally cleaned before moving in.


A lot of the cleaning products we use every day contain VOCs. They are found in furniture polish, air fresheners, carpet cleaners, oven cleaners and in the chemicals used in dry cleaning. Sprays can be more likely to trigger asthma than solid or liquid cleaning products, because you end up inhaling the chemicals. Some people also tell us the smell of cleaning products and air fresheners can trigger their asthma. Professional cleaners and others who use a lot of cleaning products all the time are at more risk of developing asthma.

These steps may help:

  • Avoid spray cleaners
. It's better to use solid or liquid cleaning stuffs, rather than sprays, as sprays get into the air, so they can be inhaled more easily and get further down into the airways, causing irritation. If you can, use as little of the product as possible, and open windows when you're cleaning for good ventilation. Even using spray cleaning products now and again can trigger asthma.
  • Avoid scented products
. If you think the smell of cleaning products triggers asthma symptoms, go for unscented products.
  • Consider other cleaning methods. 
The best way to avoid exposure to the chemicals found in cleaning products is to avoid using them. Use a damp cloth for cleaning instead whenever possible and look for products which are labelled allergy friendly, as these have lower levels of VOCs and are usually fragrance-free.


The products used in decorating and DIY contain certain VOCs. Some people tell us these products can trigger their asthma symptoms, although there hasn't been much research into this. If you find being around paint, glue and varnishes triggers your asthma, try these steps:

  • Look for paints low in VOCs
. There are now lots available at big DIY stores and paints are clearly labelled with their VOC levels. Low-odour, water-based gloss paints might also be slightly better for some people with asthma.
  • Always keep windows open when you're decorating.

Building work and repairs

There's a link between poor housing and asthma so it's important to make sure problems like damp, mould and poor ventilation are sorted out as soon as possible. If you have work done in your home, make sure you're not putting your asthma at greater risk.

  • Cavity wall insulation keeps a home warm and free from damp. However, some insulation materials give off VOCs, and some people feel exposure to these gases makes their asthma worse, although there's little evidence to show this happens. If you're concerned, find out what type of material is going to be used and whether it gives off VOCs, and make sure the insulation material is properly sealed once it's installed.
  • If you've got any building work planned in your home there's likely to be more dust and fumes about. Ask your GP or asthma nurse if you should take more asthma medicines while the work is going on. If you can stay with friends or family while the work is being carried out, that would help your asthma even more.

Other steps that may help

People with asthma have told us they've tried these tips for helping to reduce their risk of having an asthma attack due to triggers in the home:

Air filters and purifiers

Air filters and purifiers clean the air and can reduce the number of asthma triggers such as pet dander (flakes of skin), mould spores, dust and tobacco smoke particles. Some people tell us having an air filter or air purifier helps them with their asthma symptoms. However more research is needed to prove this. Most studies suggest that they do improve symptoms, but only if used alongside other methods. They can't remove all allergens and even a few left behind can trigger asthma symptoms.

If you're thinking of using an air filter or purifier, you need to:

  • Check what type of allergens it captures
  • Check that the air purifier is ozone-free. Some purifiers give out low levels of ozone which can make asthma symptoms worse
  • Clean and replace all filters when necessary.

Humidifiers and de-humidifiers

Some people with asthma tell us that humidifiers and dehumidifiers help with their asthma symptoms, but once again only if used alongside other methods. There isn't much research evidence about how effective they are.

Good ventilation

Keeping your home well ventilated by opening windows or using extractor fans reduces humidity. Less humidity means fewer house dust mites and mould spores. Good ventilation also helps get rid of gases produced by heating and cooking.

Opening a window is better than using a fan, or extractor fan. Fans or extractor fans need to be put in the right place so they don't just blow allergens around the room.

Asthma UK does not recommend ionisers

Ionisers give out electrostatic charges to clean the air but there's no evidence that they improve asthma symptoms. Asthma UK doesn't recommend using an ioniser because some research shows that they increase night time cough in children.

Last updated June 2016

Next review due June 2019

Asthma action plans keep all your personal triggers and medicines tips in one place. Download one now to fill in with your doctor or nurse.