We're now officially in winter in Aotearoa, something you've probably noticed with the freezing temperatures and shorter days.
Winter has many perks: Rugging up in stylish coats and boots, delicious warming winter meals, reading books inside by the fire... but all those little joys can come at a cost.
You may have noticed your skin has lost the glow of the summer months and is instead becoming dry, extra sensitive and easily irritated.
Naomi Simpson, Dyson's associate principal scientist, spends much of her time researching the environmental factors that affect skin.
"With the colder months upon us, temperatures will begin to plummet. Cold air can hold less water than warm air, so inherently winter air tends to be dry," she says.
"As we shiver indoors, we may crank up the central heating to feel more comfortable, which can dry the air even further."
Simpson says exposure to dry, cold air can result in an increased drying of the skin a process known as trans-epidermal water loss (TEWL).
"TEWL is a measure of the amount of water that passively evaporates through the skin to the external environment," she says.
"It's a completely normal process that your skin naturally regulates, however certain factors such as injury, low humidity weather conditions and products that are applied to the skin can all have an impact."
Simpson says dry, cold air can increase the rate the water is evaporating through the skin, "resulting in excessive water loss which can cause dehydration and lead to symptoms such as dry, rough, flaky, itchy and inflamed skin".
"And it's a vicious circle - when dry air takes moisture from our skin, its structure changes, making our skin less able to hold onto moisture, while also providing routes into the skin for airborne pollutants."
But if you're hunkering down indoors, you might be doing your skin more harm than good. Spending our time indoors can increase our exposure to indoor air pollution - yes that's a thing.
"Pollution sources like urban pollution, particulate matter and pollen enter the home and combine with indoor sources like cleaning products, pet dander, scented candles, indoor paints and cooking fumes," she says.
But surely cleaning our homes thoroughly is the best way to get rid of pollutants? Apparently not.
"Some of the volatile organic compounds (VOCs) found in our homes can come from the chemicals in cleaning products we use on kitchen surfaces, bathrooms and windows," says Simpson.
"Limonene is one of the compounds that makes cleaning products smell like citrus, but it can react with naturally-occurring ozone in the home to create formaldehyde."
Oh.
And that cozy winter candle habit? It's doing you no favours either.
"Some of the things we might enjoy at home like flowers or scented candles can also be sources of indoor air pollution. Rather than avoiding them completely, try lighting candles only in moderation - for example in the evening - ensuring you ventilate the room, or use a purifier afterwards to help remove any remaining VOCs."
Otherwise, you may be impacting your skin more permanently than you'd like - and apparently not even expensive moisturisers can help.
"There has been a significant amount of research in recent years that shows how pollutants can contribute to the 'cracking' of the lipids in skin and weakening the very outermost layer of the skin," Simpson says.
"Different pollutants can interfere with its normal function through oxidative damage, with scientists observing that it can lead to skin aging, inflammatory or allergic conditions, psoriasis and acne."
If you've been suffering skin irritations and inflammation, controlling your indoor environment can be a necessary step in the winter months, says Simpson.
"But air pollution and humidity levels are an invisible problem - not visible to the naked eye."
Humidifiers are a great way to add some more moisture in the air, if you have cracked or irritated skin. It's recommended to use them in conjunction with an air purifier, which will help to maintain low indoor pollution levels.
There are many high-quality air purifiers available in New Zealand from brands like Breville, Xiaomi, Phillips and Winix, as well as Dyson.
If you are looking at purchasing one, here are some things to look out for, according to Simpson.
Fully sealed filters: These don't allow the airflow to bypass the filter so you can be sure the machine is properly filtering the air of particles and gases
Dual filters: HEPA or other types of particle filters remove particle pollutants from the air like dust, pollen and pet dander. If you can, also look for a machine with an activated carbon filter that will absorb VOCs, NO2 and other gases
Fan functionality: These are designed to project clean air across the room, not just in the corner where the machine is sitting
Last month, Dyson launched its latest purifiers in New Zealand with new solid-state formaldehyde sensing technology, designed to capture ultrafine dust and allergens, and destroy potentially dangerous VOCs including formaldehyde
