A friend forwarded this to me and I find it useful to share the information to you.
This is specially relevant for our aircon cars here in RP, where we always keep all the windows closed and the temperature goes up to more than 100o F. Please note and circulate... Do not turn on A/C immediately as soon as you enter the car! Please open the windows after you enter your car and do not turn ON the air-conditioning immediately. According to a research done, the car dashboard, sofa, air freshener emits Benzene, a Cancer causing toxin (carcinogen- take note of the heated plastic smell in your car). In addition to causing cancer, it poisons your bones, causes anemia, and reduces white blood cells. Prolonged exposure will cause Leukemia, increasing the risk of cancer may also cause miscarriage. Acceptable Benzene level indoors is 50 mg per sq. ft. A car parked indoors with the windows closed will contain 400-800 mg of Benzene. If parked outdoors under the sun at a temperature above 60 degrees F, the Benzene level goes up to 2000-4000 mg, 40 times the acceptable level... & the people inside the car will inevitably inhale an excess amount of the toxins. It is recommended that you open the windows and door to give time for the interior to air out before you enter. Benzene is a toxin that affects your kidney and liver, and is very difficult for your body to expel this toxic stuff.