According to Allergy UK, chemicals found in household products, including bleach and air fresheners, can cause direct allergy-type symptoms in some people.
Reducing the number of chemicals that you and your family are exposed to on a daily basis can help.
Household products: what to avoidAir fresheners contain substances called volatile organic compounds (VOCs), which some studies suggest can cause asthma in children. Synthetic fragrances, such as artificial musks, can also cause allergic and asthmatic reactions.
What's the alternative? Open a window and buy some odour-absorbing rubber plants or spider plants. Or make your own air freshener by putting a teaspoon of baking soda, two tablespoons of white vinegar and two cups of water in a spray bottle.
Bleach contains sodium hypochlorite, a chemical that gives off toxic fumes that can irritate the eyes, nose, throat and lungs.
What's the alternative? Use borax powder, a natural mineral that you can buy from the chemist, diluted in hot water (a teaspoon per litre) with a couple of tablespoons of vinegar added.
Oven cleaners: some of these contain sodium hydroxide, a highly toxic chemical that can irritate your airways and make it hard for you to breathe.
What's the alternative? Put a heatproof dish filled with water in the oven and turn on the heat for a while to let the steam soften any baked-on grime. Then when the oven has cooled, make a paste using equal measures of salt, bicarbonate of soda and vinegar, spread it over the oven surfaces and scrub off using a scouring pad.
Spray polish contains VOCs and synthetic fragrance (see air fresheners, above).
What's the alternative? Use a natural wax polish, such as beeswax. Work it into your wood surfaces and buff until you get a shine.
Toilet cleaner often contains naphthalene, the fumes from which can irritate the eyes, nose, throat, lungs and skin.
What's the alternative? Use vinegar to soften any limescale. Pour half a bottle into the bowl last thing at night, then give it a good scrub in the morning.
Washing powder sometimes contains sodium carbonate, a substance that can cause allergic skin reactions.
What's the alternative? Only use non-biological washing powders, as these are less likely to irritate the skin.
Window/glass cleaner can irritate the skin as well as the eyes and lungs due to the overpowering smell of ammonia you get when you open a bottle of window or glass cleaner.
What's the alternative? Add a couple of tablespoons of vinegar to a small bucket of warm water, wash, then dry with a clean cloth.