Stressed out? You need to learn to chill — both for your sake and for your kids.  

Sure, we all know that stress is not good for our health. It wreaks havoc on the heart, the mind and the immune system. But did you know that your stress can have serious effects on your kid's health, too? A new study from researchers at the University of Southern California found that children living in high-stress households are more vulnerable to the damaging effects of traffic pollution than children whose parents are not stressed.  

For the study, researchers measured the lung function of about 1,400 children living in southern California. They also measured the level of traffic pollutants the children were exposed to by sampling almost 1,000 different sites around the area. The children's parents filled out questionnaires regarding their stress levels and how often they felt out of control on a daily or weekly basis.  

After following the kids for six years, researchers measured the changes in each child's lung function as traffic in the area fluctuated. The results? The kids from higher stress homes were more greatly affected when traffic pollution worsened than kids whose parents weren't stressed. Their lung function deteriorated up to 5 percent more than kids in the same area from less stressed out homes.  

That's a big difference — and as good a reason as any to cut back on the stress.

The study was recently published in the American Journal of Respiratory and Critical Care Medicine.

Parental stress increases the effect of pollution on kids
New study finds that kids in higher stress homes are more vulnerable to the effects of pollution.