Question: While I love the "new car scent" of my new SUV, I can't help but think that it's not good for me to breathe in those chemical fumes. How dangerous is it?

Answer: The new car smell that many of us love is nothing but glue and plastic fumes given off from a freshly manufactured car. Despite the alluring scent, chemical fumes like those aren't healthy to breathe in.

A 2001 Australian study found the following chemicals released from a new car's interior: benzene, cyclohexanone, and styrene. They reported anecdotal complaints of headache, disorientation, and eye irritation in new cars.

A Japanese study found that the volatile organic chemicals in a new minivan were over 35 times the health limit the day after its delivery. They had fallen under the limit in four months but increased again in the hot summer months, taking three years to permanently remain below the limit set by the Japanese health ministry.

Many of the volatile compounds released are considered carcinogens, but short-term exposure to new car fumes isn't believed to increase your risk of cancer. High levels of new car fumes rapidly dissipate within a few months. Leaving your car windows partly open and using the cooling/heating system to bring in fresh air will help dissipate the fumes more quickly.

There are no EPA regulations of new car fumes since they dissipate within a few months. Believe it or not, the standard measure for car manufacturers is to keep the fumes to a level that prevents repeated fogging of the window interiors.

Gray vs. white hair

Q: Why does some people's hair turn gray, while others' hair turns white?

A: Leaves turn beautiful colors each autumn as they lose their pigment, die, and fall off the tree. As we age, our "leaves" turn gray or white as the hair's pigment cells, which give hair its color, die.

This loss of pigment, or melanin, is due mainly to the natural aging process and genetics, but also due to things we do to our body.

For example, have you ever noticed that some longtime smokers look older, grayer, and more wrinkled than they should for their age? A 1996 research study published in the British Medical Journal looked at 152 men and 152 women younger than 50 who smoked. They observed that 14 men and 67 women developed gray hair before the age of 50, compared with just 7 men and 27 women of the same ages who were nonsmokers.

While they were unable to explain the association between smoking and grayness, they speculated that smoking may somehow accelerate the biological clock. Alcoholism and poor nutrition are two other factors that may affect hair.

Wrinkles (sun damage excluded), gray or white hair, and hair loss are just a few of the age-related changes programmed into each of us. As we unravel the mysteries of our DNA, we may one day gain the ability to repair defective or damaged genetic information. While reversing gray hair seems trivial when compared with other more serious health concerns, the aging process is linked to serious diseases such as Alzheimer's.

The time in your life when gray or white hair will appear is largely inherited, so if either of your parents or older siblings develop premature grayness, so too may you. For many folks like me, any color is better than no hair at all.

Mitchell Hecht specializes in internal medicine. Send questions to him at: "Ask Dr. H," Box 767787, Atlanta, Ga. 30076. Due to the large volume of mail received, personal replies are not possible.