Anyone who lives in a city knows that, well, it’s a bit dirty. We choose to ignore it, as a bit of public transport grime and persistent traffic fumes are the trade off we make to live in a place that has decent nightclubs and Uber. But the effects that daily dirt has on the skin are not to be underestimated.

A recent study published in the Journal of Investigative Dermatology found that higher levels of nitrogen dioxide (one of the main pollutants from traffic fumes) in the air were linked to an increase in liver spots (those hyper pigmented lesions) on the face. These findings are just the latest in a long and steady stream of research into the impact that pollution has on our skin.

“The way that pollution works on the skin is that unfortunately it just causes the increased and faster degradation of collagen and elastin,” explains Dr Maryam Zamani, an aesthetic doctor and consultant at London’s Cadogan Clinic with a specialty in ophthalmology.

“Those are the building blocks of skin, so if you’re damaging the new versions of those coming up, then you’re going to have more fragile skin going forward. You’ll have more red vessels, more lines and wrinkles, you’ll have less hydration because you’re skin won’t be able to hold on to moisture as well as it did before. So all of these things, they seem very small, but they build up.”

The main problem with pollution is, obviously, there’s no getting away from it. Your skin is the largest organ of your body and, as Dr Zamani explains, it absorbs everything you’re exposed to. Which, if you live in London, is a huge amount of nitrogen dioxide, among the highest levels in the world, in fact. To give some idea of context, in 2015 Oxford Street had broken the EU’s annual NO2 limit by 4th January, according to a report by King’s College London.

“Pollution is a chronic problem, and tends to be worse on sunny days when there is plenty of UV penetration to fuel chemical reactions, and on windless days when there is no inflow of fresh air to dilute the accumulated pollution,” explains Dr Howard Murad, dermatologist and founder of Murad skincare brand.

When it comes to talking about skin health, pollution is bundled up with that other pervasive dermatological poison: sun exposure. “All the bad things in the pollution, whether it’s oil, dirt, UV radiation, all these things cause damage and premature ageing in our skin,” says Dr Zamani.

She explains that the first signs to look out for are dryness or flakiness to your skin. “You can tell the equilibrium of your skin is a little bit off because it looks a little bit thinner, you can see those lines and wrinkles a bit more, and it doesn’t have that dewy look to it anymore,” she says. That could be down to pollution, or it could be down to you just not taking good enough care of your skin. Either way, it’s time to step up your regime.

So what should we be doing to protect our skin from the ravages of pollution? Well, basically by following the sage advice that skincare experts have been harping on about for years. If you need a gentle reminder, we’ve put together five skincare commandments to stay city skin pollutant free.

– Always, ALWAYS remove your make-up

“It’s imperative to remove make-up every evening,” explains expert facialist Kate Kerr. “Pollution sticks to foundation and causes oxidative damage while our skin should be repairing.”

– Cleanse properly, twice a day

“Not using a soap but a nice cleanser that’s pH balanced and will not strip your skin of essential oils that it needs to protect it and keep it hydrated,” says Dr Zamani.

– And exfoliate at least twice a week

For this, Kerr says, look out for alpha-hydroxy acids like glycolic, lactic and salicylic, “to thoroughly remove impurities and toxins, and to speed up cell turnover.”

– Wear an SPF all year round

“To provide the skin with its first line of defence,” says Dr Murad. Add make sure it protects against UVA rays as well as UVB (look for the words “Broad Spectrum” on the packaging.)

– Load up on anti-oxidants

“Anything that has a stabilised form of vitamin C in it is really important to help combat any free radicals that sit on the skin,” says Dr Zamani. Kerr also recommends looking out for vitamin E, resveratrol, and glutathione.