Lead in gasoline, which was used in cars until 1996, has polluted the bodies of millions of Americans through exhaust fumes. This has had a detrimental effect on their intelligence quotient.
The average IQ loss is 3 points per US citizen
Americans have just learned that they have paid a high and unexpected price for their high dependency on Automobiles: exhaust pollution containing lead dust, which was one of the ingredients in gasoline until 1996, is estimated to have lowered the IQ of 170 million US citizens, almost half of the country’s population! This is the conclusion of a study carried out by Florida scientists and published in the Journal of the National Academy of Sciences.
Inhalation of lead particles interferes with brain development and cognitive abilities
According to this study, Americans’ exposure during their childhood to exhaust fumes from cars running on leaded gas has cost them 824 million total IQ points collectively. These figures mean nothing until they are explained: this overall drop in IQ level represents an average loss of 3 points per person, which can put people who originally had slightly below average intellectual abilities into the category of intellectual deficiencies!
Particles that are harmful to brain development
Leaded gas was banned in 1996. However, anyone born before that date, especially those born in the 1960s and 1970s when fuel consumption was at its peak, were exposed to lead from particulates in car exhaust fumes, which is very worrying. These lead particles affect not only cardiovascular health but also brain development and cognitive abilities. Lead is a neurotoxic substance that attacks brain cells when it enters the body. It affects all age groups, but children are particularly vulnerable.
By 1996, millions of Americans had been contaminated by lead added to petrol in cars.
“Lead can enter the bloodstream in the form of dust when inhaled and cross the blood-brain barrier into the brain,” says Aaron Reuben, one of the study’s authors.
Up to 7 points of IQ loss in the most exposed children
The study was based on data on blood lead levels in US children, the use of lead-containing gases, and population statistics. By comparing these data, we were able to determine the likely lifetime lead exposure levels for each American alive in 2015. And this is where the IQ loss figures came in: up to 6 points for children born in the mid and late 1960s with the highest lead levels, and as high as 7 points for the most exposed children.
“These figures really shocked me,” admitted Michael Mc Farland, co-author of the study. 170 million Americans had clinically worrying levels of lead in their blood during childhood. The introduction of lead in gasoline in 1923 was actually intended to keep the engines in good working condition.