The average American spends nearly an hour a day commuting, a number that is rapidly increasing.
Now, the research has found that Californian car users may be exposed to above acceptable levels of harmful chemicals during their daily work trips.
Estimating travel time from census data and using measurements of chemicals detected in previous studies, the new study found that trips of more than 20 minutes put people at risk for unacceptably high levels of two carcinogens used in manufacturing of automobiles.
At first glance, it may seem worrying news to anyone who spends a lot of time behind the wheel on their daily commutes. But there are many factors at play, so let’s sum up a little.
The distinctive smell of a new car gives an idea of what is going on here. The materials used to equip cars, from hard and soft plastics to adhesives, fabrics and foam, contain some chemicals that can slowly leak into the air (the technical term is ‘waste gas’) or hitch a ride in the dust.
“These chemicals are very volatile, moving easily from plastics and textiles to the air you breathe,” said environmental toxicologist David Volz of the University of California at Riverside, co-author of the study.
Volatile compounds can accumulate in small spaces, such as inside a car (unless you open a window for fresh air).
Although much research has so far focused on outdoor air pollution and its impact on health, and in indoor environments, such as workplaces or homes where people spend most of their days, this study suggests that chemicals accumulated inside vehicles can also be a concern – for some drivers.
The study aimed to estimate when a person’s exposure to known carcinogens likely exceeded safety limits based on the time passengers spent in their vehicles and the levels of five chemicals detected inside cars in previous studies.
The researchers predicted that passengers’ daily exposure to two of the five chemicals studied – benzene and formaldehyde – would likely exceed levels considered safe or allowed by California health officials after 20 minutes. The probability continued to increase the longer a person traveled.
The two chemicals of concern are not major unknowns, but they certainly deserve attention. Benzene is found in rubber and paints, and formaldehyde is used in carpets and paints, both of which are included in California’s long list of Proposition 65 carcinogens. What’s new here is to examine the risk that these chemicals can pose specifically to drivers.
“Our study raises concerns about the potential risk associated with inhaling benzene and formaldehyde for people who spend a significant amount of time in their vehicles, an issue that is especially relevant for congested areas where people have longer trips,” the authors of the study wrote.
Perhaps unsurprisingly, a larger fraction of people had a high chance (over 1 in 10) of exceeding cancer risk limits for benzene and formaldehyde on their daily commute in areas around San Francisco and the notoriously crowded Los Angeles.
“Of course, there is an exposure range that depends on how long you stay in the car and how much of the compound your car is emitting,” which may depend on the age of the vehicle and the ambient temperature, said the graduate student and study the lead author Aalekhya Reddam, also from the University of California Riverside.
In other words, just because something is listed as a carcinogen does not mean that it will certainly cause health problems – it depends on the dose to which people are exposed and how often.
Even known carcinogens are unlikely to cause cancer below certain limits, and limiting your exposure to harmful substances goes a long way in reducing any associated risk.
In addition, the poor health outcomes seen among passengers – which include higher rates of cancer – can result from a combination of inactivity, obesity and shorter sleep, which often comes with long trips. These factors were not considered in this study.
Some people, however, have no option but to travel by car – or perhaps they are taxi drivers, whose work It is to drive. To reduce the risk of exposure, more could be done during the car’s manufacturing process to replace chemicals such as benzene and formaldehyde with less harmful alternatives, the researchers said.
“As people with long journeys are an already vulnerable subpopulation, additional measures may be needed to mitigate the potential cancer risks associated with exposure to benzene and formaldehyde,” the pair wrote in their article.
“There must be alternatives to these chemicals to achieve the same goals when making vehicles,” added Volz. “In that case, they must be used.”
Improving access to public transportation and bicycle networks can also give people more options for getting to work, while adding some incidental exercises to their daily commute and helping to alleviate traffic congestion that obstructs city roads. .
The research was published in International Environment.