We spend about 90 percent of our time indoors – so why are we less aware of indoor air quality than outdoor?
Everyone knows that outdoor air pollution affects our health, and there are regular campaigns to improve it. The main cause of outdoor air pollution is petrol-driven vehicles.
But we spend about 90 percent of our time indoors, either at home or at work, and there, air quality can be equally bad – in fact, worse. Yet few people seem to be aware of the causes, results or solutions regarding indoor air pollution.
Poor indoor air quality has been linked to lung diseases such as asthma, Chronic Obstructive Pulmonary Disorder and lung cancer. It can be caused by dust, dirt, gases, chemicals or organic matter in the air, and at its root can be the way we build, cook, clean and maintain our buildings.
Indoor air quality can be particularly important to anyone who has underlying health issues such as asthma, and in this time of the coronavirus pandemic, it’s particularly important to pay attention to the way buildings are ventilated. Children are particularly susceptible to indoor air pollution as their lungs are still developing, and their airways are narrower.
Causes and symptoms
Breathing polluted indoor air can lead to respiratory infections, with symptoms such as runny noses, dry throats, sore eyes and sinuses, to shortness of breath, wheeziness, and in the long term to increased risk of pneumonia, COPD, lung cancer, heart disease and stroke.
The main causes are:
- Chemicals used in cleaning or decorating
- Materials used in construction such as asbestos
- Tobacco smoke
- Poor ventilation leading to damp and mould
- Allergies caused by pets or dust mites
- Outdoor pollution getting indoors
The main chemical culprit in indoor air pollution is volatile organic compounds, so-called VOCs, used in household cleaning and decorating materials, or bleach and ammonia used in cleaning compounds.
VOCs such as acetone, xylene and formaldehyde are found in detergents, furniture polish, air fresheners, carpet cleaners, oven cleaners, paint strippers, varnishes, glues, pesticides and fungicides, and evaporate into the air and can be inhaled. Chemicals with fragrances are particularly likely to contain VOCs, which studies suggest can cause allergic reactions and asthma.
Studies also show that that cleaning workers who use these chemicals over long periods may sustain lung damage. Carpets, furniture and flooring often contain formaldehyde which can be a lung irritant.
To reduce exposure to VOCs you should try to use allergy-free cleaning compounds, and liquids rather than sprays. Make sure your home is well ventilated when you clean, keep children away from cleaning products and dispose of packaging carefully.
Cook with care
Another main source of indoor air pollution is cooking and heating. Cookers, heaters, stoves and open fires can all release pollutants into your home, either in the form of particulate matter (PM), microscopic particles of dust, or as gasses including carbon monoxide, nitrogen oxides and sulphur dioxide. These can cause lung and heart disease. Carbon monoxide poisoning can cause headaches and flu-like symptoms, and can be fatal in severe cases.
To minimise indoor air pollution from cooking and cleaning:
- Make sure cooker and heater flues and chimneys are serviced
- Don’t burn wood or coal in open fires, and never burn rubbish or packaging
- Service cooking and heating appliances regularly
- Fit extractor fans above all cooking appliances
- Fit both smoke and carbon monoxide alarms and service them regularly
Allergies to house dust mites, pet dander and mould spores are common, and may cause breathing problems, particularly in people with asthma.
Dust mite droppings will settle into pillows, mattresses, duvets, carpets and upholstery and are hard to get rid of completely. You can try using mattress covers, vacuum cleaning, ventilation, freezing, washing, air filtration or air ionisers.
Pet dander (dead skin flakes) from furred animals and birds can also cause allergic reactions and is also hard to dispose of. The only solution seems to be regular cleaning of the home and the animal, and restricting contact – for instance you may consider not letting your cat or dog sleep on your bed.
It’s often thought that candles or incense can improve the atmosphere in a home, but in terms of air quality, they’re not recommended – both emit particles and other pollutants, incense sticks more than 100 times the number of fine particles as candles. Both can emit formaldehyde and VOCs, so never concentrate a large number of them in a small space.
The most significant indoor air pollution chemical health risk from building materials is asbestos, Though this hasn’t been used in new buildings since 1999, it may still be present in old buildings, and can cause lung disease and cancer if inhaled in particle form. If it is found in your building, don’t disturb it, get it removed by accredited professionals. The same applies to fibreglass insulation.
Another potential indoor air pollution problem in certain areas is radon, a naturally occurring gas which can accumulate in poorly ventilated buildings. You can find out if your home is built on a high radon area at the website www.ukradon.org, where you will find advice on protecting against it.
Of course tobacco smoking in doors is a major cause of poor air quality, and the main cause of preventable illness and death. You should ideally stop smoking altogether, but short of that, you should smoke outdoors, or take up vaping – still not provably harmless, but less harmful than tobacco.
- It’s important to ventilate your home well by opening windows, but check local pollution levels using DEFRA’s Daily Air Quality Index to decide when to shut your windows
- Make regular checks for condensation, damp or mould, and repair leaking roofs promptly
- Don’t dry washing indoors, use a tumble drier
- Set indoor temperature to a comfortable level, recommended 18°C (64°F).
- Close bedroom windows at night to avoid inhaling cold air
- Consider investing in an air quality sensor which can measure carbon monoxide and dioxide levels, particulates, VOCs, humidity and temperature.
Many of the same conditions causing indoor air pollution can apply at work, but you could also be exposed to other causes of allergic reaction and health risks such as wood dust, spray paint, flour dust, oils, welding byproducts, silica dust and industrial agents.
Workplace regulations are in place to protect you against these hazards and there should be a risk assessment to identify possible causes of harm. Talk to your health and safety representative or report potential problem to the Health and Safety Executive.