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Glossary

1.What is formaldehyde?

  • Molecular formula: HCHO
  • Molecular weight: 30.03
  • Melting point: -92°C
  • Boiling point: -19.2°C
  • Specific gravity in 1atm: 1.067

Colorless gas with irritating odor at room temperature. Flammable.
Very soluble in water and ethanol.
A 37% solution in which formaldehyde is dissolved in water is generally called formalin (it is very easy to volatilize).
Since formaldehyde is a polyfunctional compound, it easily forms a polymer, so various excellent and inexpensive formaldehyde resins are produced in large quantities.

2. Sources of formaldehyde

  • Industrial raw materials: Adhesives for wood used in manufacturing processes of plywood, flooring, particle board, laminated wood and the like, paper strength enhancing agent added in the process of making backing paper of wall paper, insulation materials
  • Preservatives: adhesive for wallpaper, biological specimen
  • Cigarette smoke, open stove
  • Permanent press shirt
  • Presence in trace amounts in nature (Japanese red pine wood, Japanese cedar wood, Japanese cypress wood, dried shiitake, fish meat etc.)

3.Effects of formaldehyde on the human body

Carcinogenicity of formaldehyde:
Evaluated by the American Conference of Governmental Industrial Hygienists (ACGIH) as "a substance suspected in epidemiological studies or animal experiments with limited carcinogenicity to humans."
Assessment of effects to human body by short term exposure of formaldehyde (Source: ECA - Commission of the EC)

Effects Formaldehyde concentrations (ppm: parts per million)
Estimated median Reported value
Odor detection threshold value 0.08 0.05~1
Visual detection threshold value 0.4 0.008~2
Throat inflammation threshold 0.5 0.08~3
Nose and eye irritation 3 2~3
Can endure 30 minutes (lacrimation) 5 4~5
Strong lacrimation 15 10~21
Critical to health, edema, inflammation, pneumonia 31 31~50
Death 104 50~104

4.Sick House / Sick House Syndrome / Sick Building Syndrome

There are many reports that indicate various physical disorders have happened to residents due to indoor air pollution caused by chemical substances in houses and buildings, either newly constructed or renovated, due to high airtightness of houses and use of building materials and interior materials that dissipate chemical substances.
It is called Sick Building Syndrome because symptoms are diverse, and many parts are still unknown, including mechanism of symptom occurrence, and it is considered that various complex factors are involved.

5.What are the chemical substances causing these problems?

Guideline value of indoor concentration of chemical substances (Ministry of Health, Labor and Welfare)
(1)(9) are substances regulated by the Building Standards Act. (1) to (6) are six substances whose concentrations can be measured by housing performance indicator

  Guideline value  
Thirteen substances
specified by the
Ministry of Health,
Labor and Welfare for
concentration
guidelines
(1)Formaldehyde 0.08ppm Synthetic resins such as urea, melamine, phenol and the like used for plywood, particle board, wallpaper adhesives and the like, preservatives such as adhesives and some glue
(2)Acetaldehyde 0.03ppm Some adhesives, antiseptics etc. using formaldehyde or similar substance
(3)Toluene 0.07ppm Adhesives for construction of interior materials etc., paints, etc.
(4)Xylene 0.20ppm Adhesives for construction of interior materials etc., paints, etc.
(5)Ethyl benzene 0.88ppm Adhesives for construction of interior materials etc., paints, etc.
(6)Styrene 0.05ppm Insulation materials etc. using polystyrene resin etc.
(7)Paradichlorobenzene 0.04ppm Insecticide for clothing, fragrance for toilet etc.
(8)Tetradecane 0.04ppm Solvents such as paints, kerosene
(9)Chlorpyrifos 0.07ppb
(0.007 ppb for children)
Termite removal agent
(10)Fenobcarb 3.8ppb Termite removal agent
(11)Diazinon 0.02ppb Insecticide
(12)Di-n-butyl phthalate 0.02ppm Plasticizers for paints and adhesives
(13)Di-2-ethylhexyl phthalate 7.6ppb Plasticizers for wallpaper and floor coverings

*At 25°C. ppm: concentration in parts per million, ppb: concentration in parts per billion

6.Chemical hypersensitivity (*1)

After exposed to a certain amount of chemicals or repeatedly exposed to low concentrations of chemicals for a long period of time, once in a state of hypersensitivity, some people are having hypersensitivity symptoms even for extremely small amounts of chemicals of the same type. This is called chemical hypersensitivity.
There are many unexplained parts about the causal relation and mechanism of occurrence in relation to chemical substances, and it is expected that future research will continue.

7.Total Volatile Organic Compounds (*1)

Concentration level of a mixture of several volatile organic compounds.
In order to directly evaluate the influence on health, although it is necessary to set guideline values for each Volatile Organic Compounds (VOC), it is difficult to evaluate health effects for all of a small amount of volatile organic compounds with over 100 kinds in a short period of time. Also, there are possibilities of causing new health hazards as a result of substituting substances for which guideline values are not set. Thus, it is desirable to introduce VOC contamination as a whole as a complementary indicator for realizing a comfortable indoor environment.

(*1) According to "Discussion on comfortable and healthy housing" Report (January 1999), National Institute of Public Health “Study on chemical hypersensitivity” (Chief Researcher: Tetsu Ishikawa) (FY1996)

8.Classification of formaldehyde emissions of plywood etc. in JAS (Japan Agriculture Standards)

The classification of emissions is as follows.
Provided, however, that this shall not apply in cases where the registration agency or registered foreign institution recognizes that no adhesive containing formaldehyde is used.

Performance classification (indicator classification) Formaldehyde emissions
Mean value (mg/L) Maximum value (mg/L)
F☆☆☆☆ 0.3 or less 0.4 or less
F☆☆☆ 0.5 or less 0.7 or less
F☆☆ 1.5 or less 2.1 or less
F☆ 5.0 or less 7.0 or less

*Based on the desiccator method

9.Classification by formaldehyde emission in JIS (Japanese Industrial Standards)
(Classification of formaldehyde emission of adhesives etc. used for building materials)

Classification Symbol Contents
F☆☆☆☆ Grade F☆☆☆☆ Any of urea resin, melamine resin, phenolic resin, resorcinol resin, formaldehyde antiseptic, methylol group-containing monomer and Rongalit type catalyst should not be used.
F☆☆☆☆ The emission rate is 5 or less. The emission rate is 20 or less.
F☆☆☆ Grade F☆☆☆
F☆☆ Grade F☆☆ The emission rate is 120 or less.