Car and home air conditioning units provide a cooler internal environment, and may also be a possible source of drinking water in emergency situations . But there is another side to air conditioning, especially car AC units, if turned on immediately after the car has been parked for a period of time on a hot summer’s day. This is especially worrying in Middle East countries where it’s hot almost year round. Consider the following scenario:
You’ve left your car in the parking lot of a shopping mall on a scorching July or August day; and now after returning to it, and with an inside temperature is more than 70 degrees Celsius (158 degrees Fahrenheit) and you immediately turn on the car’s AC unit. Turning on the AC Unit without first opening the car windows for a few moments can result in your body receiving dangerous benzene fumes from plastic and other synthetic materials in the car’s dashboard, linings, and upholstery.
This possibility was explored on the myth-busting website Snopes:
Benzene is a toxin that is released from these parts of the car’s interior, and if large amounts of it are ingested, a number of serious health problems can occur including anemia, bone diseases, and cancers like leukemia.
Studies made concerning the levels of benzene released in this manner indicate levels reaching 2000 – 4000 mg or 40 times normal acceptable levels. This is even more true in super hot Middle Eastern locales such as the UAE and Saudi Arabia where daytime summer temperatures can reach 130 degrees or more in Fahrenheit terms.
The American Cancer Society, warns that over exposure to benzene fumes increases risks to become infected with leukemia and other blood -related diseases. Studies conducted on benzine emissions found that older cars emit more benzene toxin emissions on hot days, ending the myth that these toxins may also be caused by the “new car smell ” of newer models.
To avoid such dangers, it is advised to roll down the car windows for a few moments before turning on the AC. This enables these toxic fumes to escape and will result in them not being absorbed by the body’s lungs and circulatory system.
Even waiting as long as 5 to 8 minutes before turning on the car AC unit could be life saving in regards to preventing the absorption of Benzene and other toxic fumes, including those of plastics like polyethylene and polystyrene that make up parts of the car’s interior.
At high temperatures, these plastics emit quantities of alkyl benzenes and benzoperylene, which may cause cancer, Snopes ascertains.
A second article, by urbanlegends.about.com does disprove a good deal of the warnings noted in the Snopes article, in a second study that states:
Despite the detectable presence of volatile oganic compounds (VOCs), reaching a total of 10.9 mg per cubic meter in a new car and 1.2 mg per cubic meter in an old car, no toxic effects were observed. Apart from noting the slight possibility that allergy-prone individuals might find their condition exacerbated by exposure to such compounds, the study concluded there is “no apparent health hazard of parked motor vehicle indoor air.”
In 2011, a Cancer.org MD refuted the claims made on the circulating email:
“We found no published studies that confirm the claims of this e-mail. Benzene levels that exceed recommendations for chronic workplace exposure have been observed in some moving cars, but these levels seem unlikely in properly maintained cars.
“Still, if you’re concerned about benzene levels in cars (especially in cars with the engine running), there’s no harm in opening the windows periodically or using an air-conditioner setting that circulates air from outside the vehicle.”
The jury is out. To be on the safe side, when in doubt, open your car windows prior to turning on the AC.
More on AC Units and record summer temperatures: