When my mother makes her yearly visit from Toronto, we take a morning walk around my rural neighborhood in Tesuque. Inevitably she takes in a deep breath and exclaims, "Ah, this air is medicine!" I believe that she is right. Air in nature is oxygen- and ion-rich and the supply is constantly being filtered and replenished. Not surprisingly, the gold standard against which Building Biology measures the quality of indoor air is pristine air as found in nature.

What do you do if your household air is not up to snuff? If you suspect that something in your home is making you sick, you may need to engage the services of a professional home inspector. A variety of parameters can be tested, some with simple instrumentation and others only through expensive laboratory procedures. There is no single magic machine that can test your home for every possible problem, so doing a little safe detective work before calling an expert will save time and money and help you to reach an accurate diagnosis.

You already own a sublimely sensitive instrument: your nose is a formidable investigative assistant with an astounding long-term memory. Have you ever revisited a place after many years' absence and noted that the familiar, distinct smell of the place piques your memory? The unique smell of burning charcoal in Costa Rica, the aroma of fresh-ground coffee in Paris, the acrid waft of steel wheels grinding on tracks in a city metro - these are some of the smells locked in my personal olfactory memory. Many people can smell an incredible one-part-per-million or more. This talent, once a crucial survival tool for our hunter-gatherer ancestors and now dulled by the assaults of modern life, can be cultivated to your advantage. Many problems can be detected through their odors. Volatile organic compounds (VOCs), some molds, some pesticides, dust, and gas all have distinct odors.

Upon first entering your home, bring awareness to what you smell. If there is an offensive odor, see if you can trace its source. For your own safety, do not linger there or start your own demolition. If you suspect a problem inside a wall, you could create a larger problem by breaking through the containment. Provide the area with plentiful fresh air until you can get an expert in.

If the first thing you smell is mothballs, potpourri, air fresheners, tobacco smoke, or scented laundry products, you may have already discovered the cause of your ill health. These substances contain a constellation of petrochemical toxins that are harmful when inhaled. They should be eliminated. The house must then be well-aired and cleaned before any further nasal investigation can occur.

The nose knows a lot, but it does have its limitations as a diagnostic tool. Once you have been in a space for just a few moments, you are no longer able to distinguish smells due to a phenomena called "olfactory fatigue." Your first few whiffs, each time you enter, are all you've got. In addition, many serious indoor-air-quality problems have no odor whatsoever. These include carbon monoxide, radon, some pesticides, and some molds.

Even without a serious hidden defect or blatant use of toxins, household air becomes polluted through the daily activities of humans breathing, cooking, bathing and washing clothes. In the absence of mechanical ventilation, airing out a home as a part of a regular cleaning routine will get rid of stale air and replace it with fresh, vital air - especially if that outdoor air is around Santa Fe.

Note that although do-it-yourself tests may indicate that a problem is present, consultation with a remediation specialist is often required for accurate diagnosis and safe, effective remediation.

Paula Baker-Laporte FAIA, an architect and certified Building Biology practitioner, is the principal of Baker-Laporte & Associates and EcoNest Design. She is primary author of Prescriptions for a Healthy House and co-author with husband Robert Laporte of Econest: Creating Sustainable Sanctuaries of Clay, Straw and Timber.