The Importance of Indoor Air Quality and Ventilating Our Homes
With our long, cold winters and short, cool summers, we obsess about making our homes feel nice and cosy, sealing ourselves in and shutting the world out. We want to increase energy efficiency and decrease our heating costs. We want to light fires, close doors and banish drafts to ensure maximum snug-as-a-bug-ness. But, just like us, our homes need to breathe. This snugness comes at a price.
If our homes are poorly or inadequately ventilated, not only are we trapping ourselves inside with a whole load of mould-loving moisture, but we are also exposing ourselves to more concentrated levels of indoor pollutants, the sort that cause all kinds of allergies and ailments. These accumulate and can have a detrimental effect on our health and life expectancy, and a damaging effect on our homes.
Moisture and humidity
We create moisture by literally living and breathing. Our daily routine of showering, cooking, washing and breathing produces litres of moisture a day. We want to keep humidity levels indoors at about 40-60% and stop moisture condensing on cold spots. Whilst water vapour itself is not necessarily a bad thing, too much moisture in the home can be. High humidity levels create a breeding ground in which mould, mildew and mites absolutely thrive. Consistently high humidity levels often cause a degradation in the fabric of the building and can increase interactions with some indoor pollutants, further decreasing the quality of the air we breathe. In older houses there are often gaps around windows and doors which brings fresh air in, but in newer houses, things are usually a little more insulated and airtight so we need either natural or mechanical ways to ventilate in order to keep humidity at a safe level.
Indoor pollutants
These pesky particles are everywhere and in everything, they’re biological and chemical. They’re gaseous and particulate. If it smells, it’s emitting particles… and if it doesn’t smell, it’s probably emitting particles. Some of the main culprits are:
VOCs Volatile Organic Compounds – contained in paints; glues, varnishes & fire retardants in furniture & carpets; scented candles & incense; cleaning products; aerosols; toiletries
Particulate Matter Microscopic airborne particles (pm2.5 – 10 µm) from log fires, cooking, dust, pollen, fungi spores, mites, exhaust fumes, construction sites and smoking
Gases Carbon dioxide; Carbon monoxide; Nitrogen oxides; Ozone; Radon; Formaldehyde (a proper bad ‘un) - from combustion, breathing, off-gassing
Arrgh, so what can we do?
Fortunately, there are some simple and inexpensive things we can do right now to help. And some other things to plan for when you have the opportunity to make changes:
Increase ventilation and air circulation
open windows especially when cooking or washing (not at rush hour on a busy road though); use trickle vents in your windows (they can be retro-fitted if you haven’t got any); ensure your cooker hood extracts to outside rather than recirculates the air; install continuous extractor fans in bathrooms and utility rooms; move furniture away from exterior walls to allow air to circulate; undercut internal doors so that there is a 1cm gap between the bottom of the door and the top of the floor finish
Reduce air-borne particulates
hoover regularly; avoid using wood-burning stoves; consider an air-purifier (with an HEPA filter); switch from a gas hob to an electric or induction hob; use soy and beeswax candles instead of paraffin-based; don’t wear outdoor shoes indoors; wash bedding regularly; groom pets outside; use ‘trace’ or ‘minimal’ VOC paints and products; avoid harsh chemical cleaners – consider making your own using natural ingredients; avoid smoking or vaping indoors; and ventilate
Reduce humidity
have shorter showers; use lids on pans; dry washing outside; leave the dishwasher to cool before opening; when running a bath, put cold water in first before adding hot water; and ventilate!
Some of these measures may just not work for you or may require investment you just haven’t got right now, so apply a bit of common sense. Make changes where you can. If you don’t want windows open all the time because you have noisy neighbours, are worried about security or just immensely dislike the cold, then ‘purge’ ventilate by flinging them open for 10 minutes a day early in the morning. If you’re a log-burner enthusiast treat yourself to a fire on special occasions using kiln-dried wood and consider alternatives such as an electric stove, bioethanol burners or smart LED candles (they’re obviously not the same as a real fire but the warm flickering glow can be very realistic).
If you’re considering any renovation work, make sure you talk to your architect and builder about the importance of ventilation, refer to Building Regs Part F, which they should be complying with.
Check on the external condition of your home (or make sure your landlord does) – Are there any obvious signs of disrepair? Is the guttering ok? Are vents and grilles clear of obstruction? If you look after the building’s roof, windows and walls, make an effort to reduce the use of pollutants in your home and properly ventilate, these measures will all help to improve your indoor air quality.
The importance of ventilating our homes cannot be overstated. It’s imperative that we understand how our lifestyles and our homes are an interwoven, complicated ecosystem which requires care, consideration and correct ventilation.
Sources:
Air Quality Expert Group. “Indoor Air Quality”. DEFRA, 2022
Dept. of Health and Social Care. “Chief Medical Officer’s Report 2022: Air Pollution”. DHSC, 2022
Alastair C. Lewis, Deborah Jenkins & Christopher J. M. Whitty. Comment: Indoor air pollution; five ways to fight the hidden harms: Nature vol. 614, 2023, pp 220-223
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