Lead from gasoline persists in the air for decades
The decade of the ’90s was an important revulsive in environmental matters. Many countries became aware of the impact that human beings had on the planet and some of the most important agreements on this matter were signed. In 1992, for example, products with chlorofluorocarbons (CFCs), which had become one of the main causes of the hole in the ozone layer, were banned. Likewise, in those same years came the ban on leaded gasoline, with the aim of avoiding the significant health problems that exposure to this metal brings.
It is tempting to think that reaching international treaties, removing harmful products from the market or changing consumption habits for more sustainable ones represents an effective and immediate solution to the problem. However, the planet has its own rhythm and the natural dynamics to regain balance can take decades or even centuries.
This is demonstrated in a study published this week in PNAS (Proceedings of the National Academy of Sciences) that has analyzed the air quality of London and has detected high levels of this element, despite the fact that leaded gasoline was banned in 1999 . “Lead from decades old gasoline is still a major pollutant in London”, Explain the researchers from the famous Imperial College in London. “Leaded gasoline represents the main source of environmental lead throughout the 20th century. Using recent and historical data on the isotopic composition of lead in airborne London particles we have found strong evidence that the sources have not changed substantially since the ban in 1999 ”.
One of the strengths of the study has been to combine recently taken data with historical data from past decades to understand the trend. The researchers collected 18 airborne particulate samples from London’s well-known Marylebone Street during the years 2014 and 2018. During that period, they also collected 20 air samples from a 24-meter-high rooftop. For comparison, they have used historical records collected in the 1960s, 1970s, 1990s and 2010s.
The findings show that although London air lead levels have fallen significantly since the ban and now meet UK air quality targets, a significant percentage of lead still persists, of which up to 40% of the lead that is present in particles in the air today comes from that type of gasoline.
The researchers state that these data prove the long-term persistence of pollutants introduced by human activities into the environment and the “need for an in-depth study of the population’s blood lead levels, as was recently done in the United States. United”. Furthermore, the findings of the London study are in line with the results of similar studies, such as those conducted in Sao Paolo, Brazil, and raise important questions about long-term lead contamination in other large cities around the world. “
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Scientific references and more information:
Resongles, Eléonore, et al. “Strong Evidence for the Continued Contribution of Lead Deposited during the 20th Century to the Atmospheric Environment in London of Today”. Proceedings of the National Academy of Sciences, June 2021, DOI: 10.1073 / pnas.2102791118.
Caroline Brogan “Lead from leaded petrol persists in London air despite ’90s ban” Imperial College London