That “new car smell” is now being considered a major source of possible indoor air pollution. Studies have been conducted due to concern over the chemicals that cause that smell in the vehicle. One such study from 2012 showed that these chemicals may be causing severe health defects, such as birth defects, learning disabilities, and cancer. These levels have been measured to fall over time, but increased temperature and UV light exposure in the car increase the levels significantly. Due to tighter restrictions, cars made in Europe have some of the lowest levels by far.