Preface
Equipment for Measuring Formaldehyde Concentration in Air
Four categories of equipment for measuring formaldehyde concentration in air are used. These equipment are listed in the order of their ranking as efficient tools for determining formaldehyde in houses. Table #1 lists their main features and Table #2 lists their advantages and disadvantages. More explanations follows the tables.
Table #1: Main Attributes of Formaldehyde Measuring Devices
#
|
Category
|
What it Measures?
|
How results are obtained?
|
1 | Direct-Read Passive Dosimeters, DRPD. The exposure to formaldehyde changes the color of the dosimeter. Larger exposure dose produces more intense color. | Exposure Dose, ppm*hr and Time Weighted Average concentration, TWA. | Visible color develops and can be seen by the user. Dosimeters can be sent back for digital analysis. |
2 |
Passive dosimeters to collect the sample. The dosimeters have to be sent back to supplier for analysis & obtain results | Exposure dose is obtained ONLY at the end of the measurement. |
The collected sample is analyzed by GC-MS days after it was collected |
3 | Active sampler with a pump and computing capacity | Exposure dose and concentration are measured | Concentrations and dose results are obtained on site. |
4 | Active sampler with a pump but without computing capacity | Collects sample. Displays concentration |
Data are collected and displayed on site |
Table #2: Advantages and Disadvantages of the Main Formaldehyde Measuring Devices
#
|
Size
|
Weight
|
Cost
|
Ease of Use
|
Supplier
|
1
|
Credit card
|
Very small
|
Low cost
|
Very easy
|
|
2
|
Match box to cigarettes box
|
Larger
40-200 gm
|
More Expensive
|
Very easy
|
Many.
|
3
|
Electronic meter with computing capacity, memory
|
Large
250-450 gm
|
Very expensive
|
Requires trained user
|
Many.
|
4
|
Electronic meter
Without computing capacity
|
Large
250-450 gm
|
Expensive
|
May require trained user
|
Many.
|
The small size of Chemsee’s formaldehyde dosimeters, their low-cost and the fact that they allow a user to visually estimate the dose of formaldehyde that they were exposed to make them most suitable for use by home owners to assess the magnitude of formaldehyde in their homes.
Considerations Relative to Measuring Formaldehyde in a House and its Emission From Wood Flooring, Curtains, Carpets etc. Where and for How Long to Place a Detector/Sampler?
- If the 24 hrs average formaldehyde concentration, denoted TWA24, in locations most likely to have large formaldehyde concentration, is below 5 ppb, the air should be considered safe.
- If the TWA24 is over 75 ppb, mitigation or remediation strategy should be used to reduce the exposure dose.
- ANYTIME that a TWA24 greater than 20 ppb, we recommend that the tests be repeated, and repeated also in different locations, to ensure that local variations in air flow or the selection of the sampling location did not bias the measurement down.
-
Trying to determine if a remediation step indeed resulted in reducing the formaldehyde concentration and exposure.
-
Trying to determine the amount of formaldehyde that a floor board is emitting, and if the emission exceeds a given standard.
-
Trying to determine the difference in the formaldehyde concentration between different rooms, e. g. rooms where wood floor boards were placed versus rooms where no floor boards were placed.
-
Trying to determine the effect of changes in the ventilation, heating or air conditioning on the exposure level.
Where to Place a Formaldehyde Dosimeter and What to Do to Ensure Obtaining Reliable Results?
- Attached to a bed sheet or frame about one foot from the floor. Make sure that the dosimeter is open to the air and NOT covered by the sheets.
- One may attached light dosimeters such as ChemSee.com dosimeters to the collar of a person near the breathing area. The exposure recordedin this manner measures the dose that the wearer actually breathed.
- On a support about 1-1.5 foot from the floor in areas where new wood floor or paneling was installed. Make sure that the open area of the dosimeter is fully available for air to diffuse in.
- Hung to curtains, in particular new curtains.
Where Formaldehyde is Used?
Formaldehyde is a very volatile, water soluble common chemical which is used in many products including glues and polymers, wood and composite particle boards, flooring materials, certain carpets and curtain materials, embalming fluid in morgues, disinfectants and preserving material for biological tissues etc. The main reason for the disinfectant properties of formaldehyde is that it stunts the growth of bacteria and kills viruses. In this way, it eliminates bacteria that can react with the tissue and thus helps preserve flesh tissues, small animals etc. This has been the practice for years in biology/pathology laboratories etc. Obviously, toxic materials that can kill cells of bacteria will be toxic to human cells too.
Regulatory Aspects of Exposure to Formaldehyde.
Health effects of Formaldehyde.
The adverse health effects of exposure to formaldehyde include negative effects which can be seen in a relatively short time and effects which can be seen only long time after the exposure. Breathing difficulties, tearing eyes, scratchy throat are observed in a short time if the formaldehyde concentration is high. Long term exposure increases the probability of certain types of cancer and possibly of birth defects and reduced cognitive functions. The physiological harm increases as the exposure dose to formaldehyde increases. This increase happens the exposure concentration is greater and/or when the exposure time is longer. The product of the exposure time and the time-weighted average concentration, the TWA, is the exposure dose. The physiological harm increases dramatically as the exposure dose increases, i. e. the medical harm is not linearly proportional to the exposure dose. The human body can accommodate limited exposure to small doses of formaldehyde for a short period of time without showing a negative effect in a time scale of weeks or even months. However, any incremental exposure causes physiological harm and can result in immediate sickness. Some people are much more sensitive than others to the adverse effects of formaldehyde. Professor W. C. Monte in his book “while Science Sleeps” attributes many illnesses to formaldehyde formed in the body when aspartame is digested as a sweetener.
Formaldehyde and Composite Boards or Flooring Panels.
Composite boards, flooring and other building materials use formaldehyde-based polymers in two main capacities: As the glue that holds wood particles together and as a component of coatings of the wood boards, paints and varnishes. The three most important polymers used in these capacities are urea-formaldehyde, UF, Phenol-formaldehyde, PF, and melamine-formaldehyde. MF. Formaldehyde may be emitted from these polymers if they were not properly polymerized, sealed, if unreacted residual formaldehyde was retained in the polymer and several other reasons. Vapors of formaldehyde will be emitted if “free” formaldehyde is present in the board or if conditions exist that the polymer can decompose. In general, the amounts of formaldehyde emitted will decrease as time goes by but physiological damage will inflict the breathing personnel as long as there is emission from the board. Vigorous ventilation will decrease the effective concentration breathed and may accelerate the removal of formaldehyde. However, this will come at a cost: Increased energy bills.
Information On ChemSee.com/Appealing Products Dosimeters and Detectors for Toxic Gases.
Avaliable Products
Dosimeters for Monitoring Formaldehyde Gas
Product Description and Use
- Semi-Quantitative Visual Analysis
- Meets and Exceeds Requiremens Specified by OSHA.
- Electronic Reader Available or Free In-Lab Quantitative Analysis
- Detection Range of 0 to 1 ppm*hr
- Selective Response
- Small and Lightweight (Size of a Credit Card)
- Long Shelf-Life