Home Air Testing Advice

Josh Feinmann, Clean Air Advice
July 2006

Indoor air pollution is listed among the top 5 greatest environmental health threats by the US EPA, and scientific studies have shown that the air in your home or office can be more seriously polluted than the air outside—even in the largest and most industrialized cities. Since we spend such a large portion of our lives indoors—including working and sleeping—the risk of exposure to indoor air pollutants is a serious concern.

What's more, the people who may be exposed to poor indoor air quality for the longest periods of time are often those who prove most susceptible to the ill effects of indoor air pollution. Young children, whose lungs are still developing, can face an increased risk of asthma and other respiratory problems when exposed to unhealthy levels of allergens and other contaminants, and the elderly or chronically ill, who often suffer from suppressed immune systems, are also vulnerable. Lastly, sufferers of chronic sinusitis, hay fever or other allergies, or chemical sensitivities may find life unbearable in a home with high concentrations of allergens and other contaminants.

But indoor air pollution isn't just a problem for the sick: studies have shown that ill health effects from poor indoor air quality may take years to manifest themselves, and indoor pollutants can contribute to cardiopulmonary disease and cancer even in otherwise healthy individuals. Even if you don't show symptoms, the air quality in your home or office can be doing irreversible harm before you know it.

KNOW WHAT YOU'RE BREATHING

The word "Pollution" might invoke images of industrial smokestacks, oil spills, or smog-covered cities, but there are actually many sources of pollution in your home right now. Household appliances like gas stoves and water heaters, common cleaning products and solvents, even carpets and pressed wood furniture may release toxic chemicals such as carbon monoxide (CO) and formaldehyde into the air in your home. Normal household dust contains fine particles which may be harmful to some, as well as irritating pet dander and dust mites. Unseen molds and spores in your walls or ductwork may cause allergies and even toxic reactions.

So how do you know what is in the air you're breathing? A good first step is an Indoor Air Quality Test: you'll never know what pollutants are currently contaminating your air if you don't test it. Home air test kits covering a wide spectrum of pollutants and allergens are readily available and easy to use, and testing the air quality of your home or office is the single most important step to ensure that the air you're breathing is free from harmful contaminants.

TYPES OF AIR QUALITY TESTING

There are several general types of home air quality tests, and they range from comprehensive surveys of many types of indoor air pollutants, to targeted tests which focus on a specific pollutant group. Here are some examples of the most common types of home air tests:

Airborne Particulate Tests

Airborne particulate tests, sometimes known as aerobiology assays, use a special sampling cassette, coupled with a calibrated air pump, designed to capture a wide range of airborne particulate pollutants for laboratory analysis. Typically the pump mechanism draws air through the cassette at a prescribed flow rate, and particles from the air are collected on a specially-prepared glass surface inside the cassette. Once the sample is collected, it's sent back to a laboratory where the slide is removed from the cassette and examined a high magnification. The lab analyst counts each type of particle contained in the sample, giving a good general indicator of the presence and number of pollen grains, insect biodetritus (microscopic particles of insect droppings and remains), common dust components such as skin cell fragments and fibers, and finally, mold spores and fungal elements.

Because the airflow through the sampling device is calibrated, and the sample collection is timed, an aerobiology test indicates concentrations of airborne particles in "counts" of particles per cubic meter (cts/m³) or counts per gram of air. You can then compare the findings against recommended threshold limits of airborne particles to get an idea of how "clean" the air in your home is.

While other types of tests, such as mold cultures for example, might give a more specific identification of exactly what species of mold are present, the aerobiology technique should give a good indication of whether airborne particles are a potential health concern in your home environment, enabling you to choose the proper solution for managing the particle pollutants in your home, such as fitting "allergen reducer" filters in your HVAC system, or employing a HEPA filter air cleaner in sleeping areas.

Surface Microscopy Tests

You might affectionately refer to these assays as "the Scotch Tape Test." Often performed along with an Airborne Particulate test described above, a surface microscopy test collects a sample of particles which have already settled out of the air onto countertops, furniture and other hard surfaces. Comparing the results of the surface test against the airborne particle measurement gives you an idea what the particulate sources are in your home, and what percentage of particles are remaining airborne, where they can breathed in.

This simple test is performed by placing a piece of specially-prepared adhesive tape on a surface, and immediately transferring it to a microscope slide. The tape must be sterile before and after the test to avoid false results. When the sample is returned to the lab, an analyst will count the particles with the aid of a microscope, just as in the aerobiology test.

Dust and Allergen Screening

To detect the presence of dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) in household dust, a typical test involves inserting a filter bag or "sock" into your home vacuum cleaner hose, and collecting samples from your bedding, carpet and window treatments. An alternative method may involve simply collecting fine dust from the vacuum cleaner bag. Dust collected in the allergen screen test is then analyzed for dust mites and their remains, which react with chemical indicators used in the test. The presence of even a small amount of dust mites suggests that countermeasures are needed to prevent a widespread infection, as dust mites are a well-known trigger for allergies and potentially dangerous asthma attacks.

Mold Tests

Since mold is a suspected cause of a majority of chronic sinusitis cases, it's not surprising that home mold test kits are among the most popular indoor air testing kits on the market. And since many species of mold, including Aspergillium and Penicillium groups, produce dangerous toxins that can cause dizziness, headaches, memory loss and even life-threatening symptoms, testing for mold is perhaps one of the most important elements of an indoor air quality assessment. While airborne particulate tests and surface microscopy assays can identify the presence and concentration of mold spores in your air, a targeted mold test is designed to specifically identify the species' present, helping you to asses the danger posed by airborne mold spores in your living space.

Mold tests of various types have the same aim: to capture "viable" mold spores from the air in your home, so they can be grown in culture and identified. A viable mold spore is one which is alive and able to reproduce. In an airborne mold test, a petri dish containing culture media is left in contact with air for a prescribed amount of time—typically taped against an active air vent, or placed inside your HVAC system. The culture media is then incubated so that active mold spores can grow into colonies which can be identified in the lab.

The presence of various non-toxic molds may indicate the need for a home air purifier, such as a HEPA filter; these air cleaners are sometimes equipped with a UV lamp or other microbial element which kills mold spores, rendering them harmless. The presence of any one of several species of toxic molds, on the other hand, may mean that a professional evaluation is needed to determine the risk level present in your home. Either way, conducting a simple mold test yourself may be the first step in avoiding a problem which can seriously affect your family's health.

HOME AIR TESTING TIPS

While you can always pay a professional to send a testing crew to your home, conducting a home test kit yourself is a perfectly viable option: it will save you money, and you won't have to invite strangers into your home, or worry about scheduling an appointment at their convenience. You can complete the test when you have the time, and simply send it back to the lab and await your results. And results from a quality home air testing kit are perfectly reliable, provided you avoid a few common pitfalls:

1. Read the Instructions!

It may seem simplistic, but how many times have you assembled a piece of furniture, or a child's toy, only to find information listed in Step Five that you needed to know in Step One? This may be easy to fix if you're putting a desk together or installing a DVD player, but it may compromise your test results if it happens during an air quality test.

Make sure to allow yourself plenty of time to complete the test, and carefully read over the entire instruction sheet before starting anything. Look over the list of supplies needed, and make sure you have everything on hand. For timed tests, watch the clock carefully and don't cut the test short—or go over the allotted time. With a little care, you'll find the test much easier to complete, and your results will be correct.

2. Don't Clean Immediately Before the Test

While regular household cleaning is an important strategy for keeping indoor allergens and pollutants at bay, dusting or vacuuming a day or two before the indoor air test may skew your results, disguising potential air quality problems. Instead, let everything be for a day or two so you have a good "baseline" for the analysis. If any part of your test kit requires running the vacuum—a dust allergen screening, for example—be sure to follow the instructions carefully for best results.

3. Keep Detailed Notes

Most home air test kits of any type will include a "Chain of Custody" form or note sheet where you jot down when and where the tests were completed, or record start and stop times for timed tests. Make sure you understand the form and the questions it's asking—call the test manufacturer or reseller if you need help. Taking careful notes and making sure your times, locations, and sample numbers are straight can make a big difference in the quality and usefulness of your test results.

FOLLOWING UP

Sometimes the most important questions only raise more questions: it's the same in science as it is in life. You may find that your test results indicate that further testing or professional advice is needed, but don't let the extra steps stand between you and clean, healthy air for your home and family. In any case, completing a series of simple home air tests should at least put you on the right path towards understanding your home's air quality, and suggest methods you may use to improve the indoor air quality in your living space.

With test results in hand, you can use the reference material here at Clean Air Advice to help you eliminate problem pollutants from your home and promote a clean, healthy environment for you and your family.

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