Most of us rarely think about what the air is doing to our skin. We worry about sun exposure, diet and sleep, but the air itself, especially in cities like Kathmandu, is damaging our complexion every day. Pollution is not just an environmental issue; it is also a skin concern, and understanding how it affects the skin is the first step towards preventing its damage.

Dr Pramod Agrawal, a hair transplant surgeon and dermatologist with over 12 years of experience in hair and skin care, explains how polluted air affects your skin.

How does air pollution affect the skin at a biological level, and what role does oxidative stress play?

Pollution accelerates the ageing of the skin on many fronts. It emits particles of harmful substances known as free radicals that destroy skin cells, damage DNA, and disrupt the skin’s natural protective layer, making it more difficult to retain moisture. With time, these particles also encourage enzymes that destroy collagen, the substance that makes the skin firm and smooth, resulting in early wrinkles and loss of elasticity. Not only does pollution compromise the skin’s protective layer, but it also destroys its internal defense system, causing it to age more quickly.

The main mechanism of skin ageing resulting from pollution is oxidative stress. Free radicals are unstable molecules formed by air pollutants that damage skin cells by robbing them of electrons, which are vital to the skin, including DNA, proteins, and lipids. When the skin’s natural antioxidant mechanisms are overwhelmed by these free radicals, oxidative stress results, causing cell damage and impaired skin repair. The outcome of this is DNA damage, an impaired skin barrier, and the destruction of natural skin oils, which lead to dry, sensitive skin.

Are certain pollutants more harmful than others, and how do they contribute to collagen breakdown?

Not every pollutant causes the same type of damage. PM2.5, the small particles present in smog and smoke, are considered the most harmful because they settle in the deepest layer of the skin, where they carry toxic chemicals and heavy metals. Nitrogen dioxide, most of which is produced by vehicle emissions, overstimulates cells that produce pigment, resulting in black spots and irregular skin colouring. Any form of pollution destroys collagen and elastin and disrupts collagen production in the skin, thus causing premature lines, wrinkles, and sagging.

Does prolonged exposure to pollution impair the skin barrier and enhance the loss of moisture?

The fats and proteins that bind the outer layer of skin to the underlying skin are broken down by pollution, creating small holes through which water can escape. The result is skin that is constantly dry, tight and easily red with irritation. What is especially concerning is that the same gaps allow more pollutants and irritants in, leading to a vicious cycle of damage that becomes increasingly difficult to break. The longer it is on, the more porous and sensitive the skin is.

Does pollution interact with UV radiation to worsen skin ageing, and are city dwellers more prone to acne and pigmentation?

Sunlight and pollution are a harmful combination. Once pollutants are present on the skin, UV rays strike them and generate a reaction that produces far more damaging free radicals than either would individually, a phenomenon the researchers refer to as photo-pollution. In addition, ground-level ozone weakens the skin’s natural antioxidants, leaving it with limited resources to withstand the attack.

For city residents in particular, pollutant particles combine with the skin’s natural oils and clog pores, leading to breakouts. They also overstimulate the pigment-producing cells, leading to dark spots, uneven skin tone, and a generally dull complexion.

What ingredients are proven to protect the skin against pollution damage?

Vitamin C, Vitamin E, and Niacinamide, among others, are antioxidants that counteract free radicals and prevent collagen degradation. Components known as barrier-strengthening, such as ceramides, hyaluronic acid, and glycerin, help seal the skin and prevent water loss.

Can pollution damage be reversed, or is prevention the more important strategy?

Some of it can be improved, but not all damage can be undone. Flat, dry, and slightly irritated skin can often be addressed with the right skincare routine. However, more serious harm—such as the breakdown of collagen and DNA damage in skin cells caused by long-term oxidative stress—cannot be fully reversed. DNA damage is particularly significant, as it affects the skin’s ability to repair and renew itself over time. This is why prevention is always better.

What daily actions should individuals in urban areas such as Kathmandu take to protect their skin?

A basic morning and evening routine is the best place to start. Clean your face first thing, then use an antioxidant serum, like Vitamin C or Niacinamide, apply a moisturiser that supports the skin barrier, and never skip SPF 30 or above. Avoid touching your face, and put on a mask when there is heavy pollution during the day.

At night, wash thoroughly to remove the day’s buildup and use a good moisturiser to help the skin repair itself. Staying hydrated, consuming plenty of fruits and vegetables, and avoiding smoking will also help strengthen your skin’s ability to withstand pollution.