What pollution causes (and we didn't even suspect)
It's a bright day, the sun is shining, the air rustles the leaves of the trees, and you want to take a deep breath. If you live in a big city, you should know that with every breath you inhale, you inject nitrogen dioxide (produced by traffic and industry), particulate matter (generated by traffic), and ground-level ozone into your lungs. These are three harmful pollutants that, according to Juan Bárcena, head of the Air Quality Department of Ecologistas en Acción, exceed the legal limits set by the European Union in Spain. Also, be aware that living on the outskirts of the city doesn't always offer guarantees, as it is precisely in this area where ground-level ozone accumulates during the sunniest months. This pollutant, in Juan Bárcena's words, "is formed from chemical reactions with other pollutants and sunlight, which is why it is higher in good weather."
But pollution doesn't just remain in the air; it spreads to water, land, and food. This is the case with persistent organic pollutants: DDT (a pesticide used against mosquitoes that transmit malaria), endosulfan (insecticide), hexachlorobenzene (pesticide), and polychlorinated biphenyls (PCBs), present in electrical equipment and old buildings. Traces have been found in remote areas: "These compounds, in addition to being transmitted through the food chain, also travel through the air: their volatility causes them to mix with warm air currents and settle in cold places. That's why traces of DDT have been found in penguins and polar bears, animals that live in places where this product has never been used," explains Juan Pedro Arrebola, an environmental pollution expert and researcher at the Biosanitary Research Institute of Granada.
None of the aforementioned pollutants are used in Spain anymore, although they remain present in the environment because they have been designed to persist for years. However, the exposure doses are below the limits established by international regulatory bodies. However, Arrebola raises a question: "We don't know if continuous exposure translates into long-term harmful effects. We also have to keep in mind that we are exposed to several pollutants, not just one."
The World Health Organization (WHO) reveals a close link between exposure to environmental pollutants and the development of cardiovascular diseases, such as strokes and ischemic heart disease, lung disease and even cancer. In recent years, in addition, different investigations and studies have begun to point to pollution as a factor that contributes to the increase in other health problems, such as allergies. But there are others less known.
1. Contributes to obesity
The relationship between pollution and obesity has been studied for ten years: "In vitro studies have shown that persistent organic pollutants have the ability to cause fat cell proliferation, in addition to being linked to alterations in fat metabolism," says researcher Juan Pedro Arrebola. At the same time, fat appears to act as a magnet for these compounds. This is evident from the study conducted by this specialist with 300 people, whose body concentrations of pollutants were measured.
"We saw that the most obese had higher concentrations of contaminants. These tend to accumulate in fat, both from food and from people," he says. Therefore, one of his pieces of advice is to watch your diet and reduce your intake of fatty products, especially large oily fish (tuna, swordfish, etc.), which accumulate higher concentrations of fat and contaminants because they tend to have a longer lifespan. "You have to moderate your consumption, especially during childhood and pregnancy, which are important periods in development," he concludes.
2. Decreases performance in children
Researchers at the Center for Research in Environmental Epidemiology (CREAL), in Barcelona, have carried out a study with 2.897 children between seven and ten years old from 39 schools in Barcelona and San Cugat del Vallés (Barcelona) who were exposed to environmental pollution caused by the traffic.
For more than a year they evaluated whether exposure to air pollutants was associated with the cognitive development of minors through tests that assessed working memory and attention span. They also measured pollution due to traffic both in the schoolyard and inside the classroom. Surprisingly, children in the most polluted schools had less growth in cognitive development than those in the least polluted schools. They found, for example, that contamination by elemental carbon particles reduced the growth of working memory by 13%.
"The observed association was consistent across cognitive measures, although it was most evident for working memory, a good indicator of learning achievement. Therefore, the reduced cognitive development of children attending schools with higher air pollution could lead to a disadvantage that should be taken into account when monitoring air quality," explains Jordi Sunyer, the study's principal investigator.
3. Generates skin problems
It seems logical to think that polluted air affects skin quality (dryness, wrinkles), and there are studies conducted by cosmetic brands that reflect this: a study conducted by Olay among more than 200 women in Beijing shows that those living in highly polluted districts have poorer skin hydration than those in pollution-free areas. However, there are no scientific studies on these effects. "It's difficult to quantify how pollution affects the skin because there are no internationally validated objective scales for measuring skin qualities (luminosity, brightness, density, etc.)," explains Dr. Cristina Eguren, assistant professor at the Dermatology Department at Infanta Leonor Hospital in Madrid.
However, according to the dermatologist, a relationship between pollution and atopic dermatitis has been found through the analysis of epidemiological data. "In the last 30 years, the incidence of this problem has tripled in industrialized countries, and it is believed that the most influential factor is pollution. Non-industrialized countries have a low rate of atopic dermatitis, but when immigrants from those countries arrive here, they acquire the same incidence rate as ours. Genetic changes cannot explain this because they occur over a short period of time," she concludes.
