If you've been working from home recently rather than the office, then avoiding the daily commute - and thus reducing your exposure to outdoor air pollution - might seem like one of the few positives that has come out of lockdown. Bad news: the air inside your home might be dirtier than you think.
Lockdown restrictions are easing, but chances are you're still spending much more time at home than ever before.
And, while we often associate the words 'air pollution' with vehicle emissions, a study commissioned last year by charity Global Action Plan found that pollution levels can be more than three times higher indoors than outdoors.
Pollution from everyday household activities, combined with outdoor pollution that's travelled inside, creates a build-up which takes longer to disperse indoors than outdoors.
Here are five ways in which you might be inadvertently allowing air pollution to build up in your home, and our tips on how to avoid these mistakes.
We speak to Professor NicolaCarslaw, Professor of Indoor Air Chemistry at the University of York and indoor air pollution expert. Watch the video below for her advice on keeping the air in your home clean.
On hot days, we naturally rush to open our windows. But the great British weather means these days are few and far between, and on chilly or drizzly days it's tempting to keep windows tightly shut.
However, ventilating is a free, easy way to improve your indoor air quality, provided you're strategic about when you open your windows. If you suffer from hay fever, you'll need to take account of high pollen times too - the Met Office weather app can tell you when the pollen count is high in your area.
Living in damp, mouldy conditions can reduce lung function, inflame your airways, cause chest tightness and throat irritation, exacerbate problems such as asthma and depression, and throw your immune system out of kilter.
Keeping your home hygienic has never been more important, but it's important to use certain cleaning products safely and in moderation. Some cleaning products can contain volatile organic compounds (VOCs), bleach or ammonia - all of which we should avoid breathing in too much of.
Houseplants are all the rage right now, especially among urban dwellers cooped up in tiny flats and dreaming of the countryside - or, at the very least, a garden.
But, while they can help break down harmful compounds in the air on a small scale, you'd need huge numbers of the right kind of plants, maintained under perfect conditions, to significantly improve your indoor air quality.
According to the Royal Horticultural Society (RHS), studies have shown that having plants at home can reduce blood pressure and improve your mood and reaction-time in computer tasks and reduce your stress - all good things if your home is now also your office.
If you have allergies or asthma, then it's important to keep your house as free as possible from pollutants, such as fine dust particles and pollen, which can aggravate your symptoms.
HEPA (High Efficiency Particulate Air) filters are a feature you may see advertised as being more effective at removing allergens from the air. These filters have multiple layers of criss-crossing fibres, which need to be able to remove at least 99.8% of particles 0.3 microns in size or bigger.
In general, we find that air purifiers and vacuum cleaners with HEPA filters are more effective at trapping common household allergens than those without, but that isn't always the case. Other factors such as how well-fitted the filter is, how carefully sealed the airways are within the vacuum cleaner also play a part.