Hot cars can hit
deadly temperatures in as little as one hour
Leslie
Minton
A
lot can happen at 160 degrees Fahrenheit: Eggs fry, salmonella bacteria dies,
and human skin will suffer third-degree burns.
If a car is parked in the sun on
a hot summer day, its dashboard can hit about 160 degrees in about an hour.
One
hour is also about how long it can take for a young child trapped in a car to
suffer heat injury or even die from hyperthermia.
Researchers
from Arizona State University and the University of California at San Diego
School of Medicine have completed a study to compare how different types of
cars warm up on hot days when exposed to different amounts of shade and
sunlight for different periods of time.
The research team also took into
account how these differences would affect the body temperature of a
hypothetical 2-year-old child left in a vehicle on a hot day. Their study was published in the
journal Temperature.
From
January through May 2018, six children died after being left in hot cars in the
United States. That number will go up. Annually in the U.S., an average of 37
children left in hot cars die from complications of hyperthermia — when the
body warms to above 104 degrees and cannot cool down.
More than 50 percent of
cases of a child dying in a hot car involve a parent or caregiver who forgot
the child in the car.
The findings
Researchers
used six vehicles for the study: Two identical silver midsize sedans, two
identical silver economy cars and two identical silver minivans.
During three
hot summer days with temperatures in the 100s in Tempe, Arizona, researchers
moved the cars from sunlight to shade for different periods of time throughout
the day. Researchers measured interior air temperature and surface temperatures
throughout different parts of the day.
“These
tests replicated what might happen during a shopping trip,” Selover said. “We
wanted to know what the interior of each vehicle would be like after one hour,
about the amount of time it would take to get groceries. I knew the
temperatures would be hot, but I was surprised by the surface temperatures.”
For
vehicles parked in the sun during the simulated shopping trip, the average
cabin temperature hit 116 degrees in one hour. Dashboards averaged 157 degrees,
steering wheels 127 degrees, and seats 123 degrees in one hour.
For
vehicles parked in the shade, interior temperatures were closer to 100 degrees
after one hour.
Dashboards averaged 118 degrees, steering wheels 107 degrees
and seats 105 degrees after one hour.
The
different types of vehicles tested warmed up at different rates, with the
economy car warming faster than the midsize sedan and minivan.
“We’ve
all gone back to our cars on hot days and have been barely able to touch the
steering wheel,” Selover said. “But imagine what that would be like to a child
trapped in a car seat. And once you introduce a person into these hot cars,
they are exhaling humidity into the air. When there is more humidity in the
air, a person can’t cool down by sweating because sweat won’t evaporate as
quickly.”
Hyperthermia
A
person’s age, weight, existing health problems and other factors, including
clothing, will affect how and when heat becomes deadly. Scientists can’t
predict exactly when a child will suffer a heatstroke, but most cases involve a
child’s core body temperature rising above 104 degrees for an extended period.
In
the study, the researchers used data to model a hypothetical 2-year-old boy’s
body temperature. The team found that a child trapped in a car in the study’s
conditions could reach that temperature in about an hour if a car is parked in
the sun, and just under two hours if the car is parked in the shade.
“We
hope these findings can be leveraged for the awareness and prevention of
pediatric vehicular heatstroke and the creation and adoption of in-vehicle
technology to alert parents of forgotten children,” said Jennifer Vanos, lead
study author and assistant professor of climate and human health at UC San
Diego.
Hyperthermia
and heatstroke effects happen along a continuum, Vanos said. Internal injuries
can begin at temperatures below 104 degrees, and some heatstroke survivors live
with brain and organ damage.
Why memories
fail
Forgetting
a child in the car can happen to anyone, said Gene Brewer, an ASU associate
professor of psychology. Brewer, who was not involved in the heat study,
researches memory processes and has testified as an expert witness in a court case
involving a parent whose child died in a hot car.
“Often
these stories involve a distracted parent,” he said. “Memory failures are
remarkably powerful, and they happen to everyone. There is no difference
between gender, class, personality, race or other traits. Functionally, there
isn’t much of a difference between forgetting your keys and forgetting your
child in the car.”
Most
people spend a lot of time on routine behaviors, doing the same activities over
and over without thinking about them. For example, driving the same route to
work, taking the children to day care on Tuesdays and Thursdays, or leaving car
keys in the same spot every day.
When new information comes into those
routines, such as a parent’s day care drop-off day suddenly changing or an
emergency phone call from a boss on the way to work, that’s when memory
failures can occur.
“These
cognitive failures have nothing to do with the child,” Brewer said. “The
cognitive failure happens because someone’s mind has gone to a new place, and
their routine has been disrupted. They are suddenly thinking about new things,
and that leads to forgetfulness. Nobody in this world has an infallible
memory.”
Ariane
Middel, an assistant professor in Temple University’s Department of Geography
and Urban Studies, and Michelle N. Poletti, a civil engineering student at
Florida International University, also worked on the study as part of the
National Science Foundation Central Arizona-Phoenix Long-Term Ecological
Research Program through ASU.
