The Skin's Defense Against Pollution Failure

People often use face masks in the cities of Asia to prevent breathing harmful pollutants. Jean Krutmann, a dermatologist began questioning whether these pollutants might also be affecting the skin. His colleagues and he began studying people in Europe and Asia exposed to car exhaust gases such as particulate matter or nitrogen dioxide, and tracked changes over time.

Krutmann’s results at first were shocking. The results of Krutmann's initial research were traffic-stopping. People living in polluted areas have higher incidences of skin inflammation and more wrinkles than those who live in cleaner environments. Krutmann, the Leibniz Research Institute for Environmental Medicine (Dusseldorf), Germany, says, "I was that one who believed nothing would come of it." "We were all amazed to find that there was strong association."

The skin acts as a soft and flexible barrier surrounding the body's tissues. Skin can soak up water, absorb medication from adhesive patches, and even release protective oils. However, this property makes the skin more vulnerable to chemicals from the surrounding environment. It is known that ultraviolet radiation can result in skin cancers such as skin cancer and premature skin ageing. Recent research has shown that common chemicals, such as pesticides, can cause severe skin damage.

Whitney Bowe, a New York City-based dermatologist, says that "just in the past ten years there has been so much science regarding new environmental stressors." While most damage to this type of exposure occurs on the skin only, there are other possible causes. Researchers are looking for new ways to prevent dermal infiltrations from chemicals and pollutants passing through the skin.

How to Make an Entry

The environment can affect skin in many ways. One way to make your skin more sensitive to chemicals is to expose it to acetone, benzene or other substances. This would allow for the substance to penetrate the skin through diffusion.

Although ultraviolet radiation doesn't penetrate the skin as deeply, it can cause a dangerous chemical reaction. It can cause unstable substances called free radicals to be created when it hits molecules of the skin that are oxygen rich. Free radicals can steal electrons from other molecules to stabilize them, a process called oxidation. These free radicals can harm the DNA of skin cells. This causes tissue inflammation, increases skin ageing, and encourages cancer-causing mutations.

However, chemicals found in our environment can often penetrate skin in subtler ways. Frederick Frasch (a physical scientist and coordinator at the US National Institute for Occupational Health and Safety, Morgantown, West Virginia) says that skin exposures can be sneaky. "If chemical ingestion is not possible, then it can be inhaled or inhaled." There are many hazardous chemicals in the smoke plumes from wildfires and other smogs, including those in Beijing.

Bowe says that some airborne pollutants can penetrate the skin's pores as small as pebbles. Other pollutants, such as the polycyclic aromatic watercarbons (or vehicle exhaust) that are found in wildfire smoke or vehicle exhaust, can pass easily through fat-filled space between skin cells. Then they enter the circulation system and can have wide-ranging effects.

Localized irritation of the skin is the most frequent problem linked to exposure to pollutants, according Sean Semple (an occupational-health specialist at University of Stirling in UK). However, there are many pollutants that can lead to long-term problems. Infertility and some types of cancer have been associated with high levels of pollutants in the air. Over time, pesticides may cause brain or nerve damage. And phthalates - chemicals that are used to make plastic more flexible and are released when it degrades - have been connected to hormonal imbalances in children and abnormal reproductive development in fetuses.

Mapping The Exposure Landscape

Environmental scientists have one goal: to determine the extent and severity of skin pollution. Krutmann asserts that pollution doesn't just occur in East Asian megacities. Krutmann says, "You can't avoid it." Krutmann has been studying a group of elderly women living in Germany's Ruhr Valley. They are subject to high levels of road traffic pollution, similar to many other areas around the world. Krutmann determined that this pollution was responsible for the rapid skin ageing observed in participants after adjusting for their socio-economic and smoking statuses. Similar results were found in urban Han Chinese women. Krutmann and colleagues also used this research in an earlier year. They found that women older than 50 who live near traffic pollutants have higher rates of eczema. Eczema is characterized by reddish-red rashes and inflammation.

Study participants are exposed to airborne phthalates through the skin.

Researchers are trying to figure out why pollution causes these problems in the lab. Guangdong Environmental Monitoring Center, Guangzhou in China conducted a 2017 study and found that particulate matter, which is a mixture of soot and exhaust particles, can cause DNA damage, cell death, and free radical formation in immortalized skin cells.

Skin is also vulnerable to airborne phthalates. Researchers have long known that these hormone-disrupting compounds are dangerous when ingested. But Charles Weschler, who investigates pollutant exposure at Rutgers University in Piscataway, New Jersey, suspected that phthalates might also pose a danger when they leach from household goods into the home environment. To measure how efficiently airborne phthalates are absorbed by skin, Weschler confined a small group of people to rooms filled with air containing elevated levels of phthalates for six hours. Participants were required to wear a respirator so they could inhale filtered air. In another trial they were allowed to inhale normal air.

Weschler found that participants absorbed about the same amount of phthalates - and sometimes even more - through their skin as they did through their lungs4. The level of phthalates absorbed by the skin could be greater in the real world, such as at home where chemical accumulation can occur over long time periods. He says, "The modeling suggested that the uptake of phthalate by skin would have been five-fold higher if we kept these experiments running for two days."

The skin might be similarly affected by the pesticides that are used in agriculture and gardening. A study by Griffith University of Nathan in Australia that looked at the health and safety of farm workers in Ghana applying pesticide chlorpyrifos (a common herbicide) to rice pads in Ghana was published earlier this year. They measured the amount of pesticide residue that reached workers' skin through their clothing. They calculated that the amount of pesticide residue that reached workers' skin was many times greater than what is recommended for a worker to avoid developing severe adverse health effects like confusion or intestinal distress. Many skin conditions have been linked with pesticides for a long time, such as contact dermatitis (a form of acne), melanoma, and even melanomas. These disorders may be caused by pesticide skin absorption, according to Ghana's results.

Researchers still don't know a lot about how skin is exposed to different pollutants over the course of a person's life. Laura Vandenberg, an environmental-health scientist at the University of Massachusetts Amherst, studies the effects of a common chemical called bisphenol A on skin. In one study, she investigated the exposure of skin to bisphenol A from thermal paper used in shop receipts6. Vandenberg concludes, based on this study and others, that many agencies involved in chemical risk assessment, including the European Food Safety Authority (6EFA), underestimate people's skin exposure to chemicals. It can be extremely difficult to determine the exact levels of exposure and predict their effects on your health. Two people working on the same farm could be exposed to different amounts of pesticides through their skin. It is also difficult to predict how pesticides will affect skin health and the general health of people due to genetic variations.

Conducting large-scale studies is the best method to evaluate how environmental exposure, skin absorption and genetic contribution affect your health. However, for the moment it is best to reduce their exposure to pollution. This includes taking common-sense precautions such as applying high-sun-protection-factor sunscreen to exposed skin and wearing protective clothing.

Krutmann suggests that creams rich in antioxidants can be used to help protect your skin from damage, especially free radicals.

Creams like these neutralize free radicals that are present on the skin and help to stop cell-destroying processes. Krutmann claims that many of these products, particularly those with vitamin E and vitamin C, are effective in limiting cell damage. Absorption of pollutants by skin is a complicated problem. Krutmann suggests that the solution might lie in strengthening the protective barrier the skin provides.