I grew up in smoggy Los Angeles and couldn’t wait to escape. I moved to another area with less population and expected cleaner air. Unfortunately, my first winter and each subsequent one after brought something equally as “yucky” called an air inversion. It brings poor air quality and a rise in allergies, asthma and other respiratory ailments. Many cities experience winter air inversions if they are located in a valley with surrounding hills and mountains.

The term, “inversion layer,” is really just a fancy name for smog. Surrounding hills and mountains trap air down in the valley, creating a layer of smog. Air down in the valleys stays cold and stagnant while temperatures in the upper elevations are warmer. This is the opposite of what you would expect.

An inversion also traps pollution. This means people breath in more pollutants than normal, including exhaust fumes from cars and factories, smoke from cigarettes, fireplaces, and trash burns, and other particulates.

This situation creates environmental health hazards for everyone but especially for certain groups, including anyone with allergies, asthma, emphysema and chronic bronchitis. Other groups at risk include the elderly, young children, anyone with heart disease or with compromised immune systems. There also is a rise in indoor allergies and other illnesses, such as colds and flu, as people spend a great deal of time indoors. The longer an inversion stays, people also begin experiencing depression.

Health experts recommend that you reduce your time outside during an inversion. Check the air quality index (AQI) each day. If you must go out, go from house to car to work, store or school. You may be at risk when the AQI is at any level besides green. In my area, a yellow AQI means a mandatory burn ban and recommendation to limit strenuous outdoor activity. Consider wearing a mask or at least, pulling a scarf over your mouth and nose.

Winter inversions mean spending more time inside. Germs get handed around more easily with these conditions. Make hand washing a top priority. Clean other places where germs hang out, including phones, TV remotes, door handles, water faucets and counter tops.