Formaldehyde

Formaldehyde has been classified as a probable human carcinogen by the EPA. Urea-formaldehyde foam insulation (UFFI), one source of formaldehyde used in home construction until the early 1980s, is now seldom installed, but formaldehyde-based resins are components of finishes, plywood, paneling, fiberboard, and particleboard, all widely employed in mobile and conventional home construction as building materials (subflooring, paneling) and as components of furniture and cabinets, permanent press fabric, draperies, and mattress ticking.

Airborne formaldehyde acts as an irritant to the conjunctiva and upper and lower respiratory tract. Symptoms are temporary and, depends upon the level and length of exposure, may range from burning or tingling sensations in eyes, nose, and throat to chest tightness and wheezing. Acute, severe reactions to formaldehyde vapor -- which has a distinctive, pungent odor -- may be associated with hypersensitivity. It is estimated that 10 to 20 percent of the U.S. population, including asthmatics, may have hyperreactive airways which may make them more susceptible to formaldehyde's effects.

If formaldehyde is suspected as the source for concern. Careful consideration should be given to weather conditions, air movement and temperature differences between indoor and outdoor air before any samples are taken. All of the conditions mentioned can affect HCHO levels in the building and short term samples taken under improper conditions could lead to missing the problem. Temperature, relative humidity and air movement can, in some cases result in levels that are double those results from other time frames. 

Mercury Vapor

While old paint has been the most publicized source of airborne heavy metal (i.e., lead), new paint has emerged as a concern as well. A 1990 report detailed elevated levels of mercury in persons exposed to interior latex (water-based) paint containing phenylmercuric acetate (PMA). PMA was a preservative that was used to prolong the product's shelf life.

Initial action by the U.S. Environmental Protection Agency resulted in the elimination of mercury compounds from indoor latex paints at the point of manufacture as of August 1990, with the requirement that paints containing mercury, including existing stocks originally designed for indoor use, be labeled or relabeled "For Exterior Use Only". As of September 1991, phenylmercuric acetate is forbidden in the manufacture of exterior latex paints as well. Latex paints containing hazardous levels of mercury may still remain on store shelves or in homes where they were left over after initial use, however.

An additional matter of concern, recently noted by the CPSC, is the sprinkling of mercury about the home by some ethnic/religious groups. According to the CPSC, mercury for this purpose is purveyed by some herbal medicine or botanical shops to consumers unaware of the dangers of the substance.

What is Off-Gassing?

The term is generally used to describe gasses which originate in certain construction materials and can have an effect on certain individuals. Some construction materials that have been known to produce off-gasses include carpeting, construction adhesives, insulation, OSB (Oriented Strand Board) sheathing and others. It is important to note if you are having any allergic type reactions when any remodeling work may have been performed to the home. Often, the onset of symptoms can correlate with installing new carpet, building an addition on the home, etc. Off-gassing from materials such as carpet can produce formaldehyde, ethylbenzene, toluene, xylene, acetonitrile, styrene, trichloroethylene, azulene, benzene, diphenyl ether, dodecane among others. For further reading on carpeting and what is being done to protect consumers, click here.

Allergens

Allergen testing is a quantitative analysis for any of the following Allergens: Cat Allergens (Fel d 1), Dog Allergens (Can f 1), Cockroach Allergens ( Bla g 1 and Bla g 2), Dust Mite Allergens (Der p 1, Der f 1 and Dust Mites Group 2), Mouse Allergens (Mus m 1), Rat Allergens (Rat n 1), Mold Allergens (Asp f 1 and Alt a 1) in household dust. Testing for Latex Allergens is also available.

Combustion Byproducts

CO, CO2, NO, NO2, aldehydes, respirable particulate and VOC's can result from indoor combustion sources including gas stoves, fireplaces, wood burning stoves, kerosene heaters, unvented gas fireplaces and others. Health effects from combustion byproducts can range from simple irritation to life threatening. Closer Look uses electronic equipment to evaluate combustion byproducts if suspected. See our Health Concerns page for further information on CO.

Evaluating the Problem

We will look at building as a whole and make note of all construction updates when formulating any hypotheses relating to the quality of the air inside of your home or building. It is important to consider ALL possible sources for contaminants when performing an IAQ investigation. This is why a thorough visual examination and interviewing the building occupants is critical when performing an investigation. In many cases, tracking down the source of contamination in a building may take the combined efforts of several experts including, construction, HVAC, industrial hygienist, certified indoor environmental consultant and possibly an epidemiologist. C.L.I. can perform air sampling for VOC's which are most commonly found in indoor air. If a compound is found which is not so common, we have the ability to cross reference with database of over 100,000 compounds to find the answer.

For further information on VOC testing click here.

Particulate

What is it? Where does it come from?

Particulate matter, or PM, is the term for particles found in the air, including dust, dirt, soot, smoke, and liquid droplets.  Particles can be suspended in the air for long periods of time.  Some particles are large or dark enough to be seen as soot or smoke.  Others are so small that individually they can only be detected with an electron microscope.

Some particles are directly emitted into the air. They come from a variety of sources such as cars, trucks, buses, factories, construction sites, tilled fields, unpaved roads, stone crushing, and burning of wood.

Other particles may be formed in the air from the chemical change of gases. They are indirectly formed when gases from burning fuels react with sunlight and water vapor.  These can result from fuel combustion in motor vehicles, at power plants, and in other industrial processes.

Chief Causes for Concern

PM. . ..

Health problems for sensitive people can get worse if they are exposed to high levels of PM for several days in a row.

Reference: U.S. EPA

Particulate Settlement Chart

Approximate Particle Sizes and Time to Settle 1 Meter

Source: John D. Spengler, Ph.D., Harvard School of Public Health, Boston, MA

C.L.I. Group, LLC can perform particulate mapping throughout the building including ductwork to assess potential problem areas. We use state of art equipment in assessing indoor particulate including a Lighthouse 3016 laser particle counter. Studies have shown that particulate which are 10µm or less can contribute to health related symptoms including SBS (sick building syndrome). We have the ability to monitor and map particulate in the range of 0.3 to 10µm.These instruments can be used for a number of important function including site monitoring, evaluating filtration and engineering controls and environmental monitoring.

A common mistake made when using particle counters during an IAQ investigation is using counters that only count particles up to 5µm. This is a mistake made by many companies utilizing particle counters. By evaluating only particulate up to 5µm, investigators may be missing half of the picture since studies have shown particulate of 10µm or less can contribute to health related symptoms.

As can be seen from the chart above, particulate in the indoor environment can remain airborne for hours or even days depending on factors such as size and disturbance. By evaluating particulate over a period of time under different conditions in the building, we can begin to spot patterns and different particulate levels in the building during different time frames or building conditions. This will help in tracking down specific sources and evaluating solutions. If the HVAC system is contaminated and cleaning and/or restoration is performed we can perform Aggressive Particle Profiling following NADCA (National Air Duct Cleaners Association) procedures.

The National Air Duct Cleaners Association recently published ACR 2002, Assessment, Cleaning, & Restoration of HVAC Systems. The following excerpt is from the chapter on Aggressive Particle Profiling Procedures.)

Particle measurements must be taken at the return air and supply air registers. A laser particle counter that has the ability to enumerate individual particle sizes and show a printout of the results must be used. The measurements must be plotted on a filter chart, which may be found in ASHRAE documents.

Particle measurements should be taken using a laser particle counter operating at a flow rate of 0.1 cfm.

Three (3) samples must be taken at the returning air entering the air-handling unit. Samples must also be taken at approximately 50% of the supply air outlets. For more aggressive sampling, one (1) sample should be procured at a supply outlet during start up of the indoor fan, and one (1) sample should be taken while lightly tapping on the side of the duct.

The particle size range to be studied includes the following: 0.3, 0.5, 0.7, 1.0, 2.0, and 5.0 micrometers. The coincidence error is less than 5% at 2X106 particles/cu. ft.

A Laser Particle Counter is also a useful tool during the initial phase of a iaq assessment in tracking potential trouble spots and sources. The equipment shown below, used by C.L.I. during assessments is each designed for different use dependant on what information is being sought. Below is some of the equipment we most commonly use during IAQ investigations along with a few IAQ problem sources.