If you park your car in a garage -- at home or in an underground structure -- keep your windows rolled up. Closed parking structures have poor ventilation, so fertilizers, paint fumes and other chemicals can build up inside. Since there's nowhere to vent, these chemicals can contaminate the interior of your car if your windows are down. When you are home, leave the garage door open to ventilate, and when you do drive, roll down the windows and let it vent out for at least 1 mile of driving.

Many people hang the iconic tree-shaped air fresheners from their rearview mirror as a way to mask odors in their cars. But you might want to reconsider them if exposure to chemicals is important to you. According to the Natural Resources Defense Council, 86 percent of the air fresheners tested contained phthalates. This chemical -- used in plastic toys and paints -- is used in air fresheners to help "carry" the scent. Thought to be an endocrine disrupter, phthalates should be avoided at all costs. To get a truly clean-smelling car, try filling a tea strainer with charcoal. Charcoal has natural odor-absorbing properties that will help your car smell like nothing at all.

We often hear about volatile organic compounds (VOCs) and the importance of reducing our exposure to them. These are chemicals that are commonly found in things like paint, carpeting and furniture that vaporize easily into pollutants. VOCs can make you and your family sick and contribute to an unhealthy indoor air environment. One way to minimize your exposure is to let new furniture off-gas before bringing it indoors. Leave new cabinets and couches in the garage for a few days to let the VOCs vaporize away.