What is the first thing you smell on entering your home? This smell is most likely something that is problematic for your health – not necessarily the most toxic smell, as some toxic fumes have no odor– but something that bothers you nonetheless.

Many homes have characteristic odors, such as cork tiles, oil burner fumes, or pine wall panels. What to you is the characteristic smell of your home? Do you remember what you smelled the first time you entered?

Here are some tips for how to best use the sniff test to help you establish a healthy home:

One of the idiosyncrasies of the nose is “olfactory fatigue,” which means that its ability to perceive odor is dulled within a few minutes of exposure. Because of this phenomenon, the following “sniff test” is best done when entering your home for the first time after being away for a long weekend or vacation.

Make sure that nobody in the home has been cooking anything within a few hours of your re-entry, as the smell of the food can overpower the sometimes subtle house smells. Spend a few moments outside clearing your lungs by breathing deeply, and focus on paying attention to what you smell.

Once you have entered the home and your sense of smell has told you what the dominant smell is, or what the dominant combination of smells is, you will need to then identify the odor. This isn’t as easy as you might think, but most people have some memory capable of identifying the source of a smell. Some ideas for odor identification include heating and cooking fuel, new carpets, mold, perfumes, scented candles, and animals. Try to isolate the smells from the blend of odors you are sometimes trying to discern, such as mold combined with a new carpet, or fresh paint and oil burner fumes.

Once you have isolated the most dominant odor, determine its toxicity. An oil burner in need of cleaning and venting is not healthy, and if you smell strong oil burner fumes, the situation needs to be remedied immediately. The cause of mold needs to be addressed, if that is the smell dominating your home. Not all smells need attending to, of course, but keep in mind that the healthiest home is one that has the most inert ingredients. Most importantly, use your intuition. Tend to the smells that bother you.

Different people can smell different dominant odors in the same home, for example: if one family member is allergic to pine terpenes, then smell of pine paneling is very strong to them, whereas another family member may not smell pine but the “new” carpet smell because they are sensitive to it.