Formaldehyde

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

A Bisensory Method for Odor and Irritation Detection of Formaldehyde and Pyridine

Author:

Berglund B., Höglund A., Esfandabad H.S.

Year:

2012

Bibliographic source:

Chem. Percept. (2012) 5:146–157

Materials and methods

Study type:

other: Odor and irritation perception

Endpoint addressed:

acute toxicity: inhalation

respiratory irritation

Principles of method if other than guideline:

A bisensory method was applied for determining the psychometric functions and absolute thresholds for odor and sensory irritation of formaldehyde in male and female volunteers

GLP compliance:

not specified

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

other: no additional information

Specific details on test material used for the study:

Name of test material (as cited in study report): Formaldehyde

Method

Type of population:

general

Subjects:

Participants:
- 31 healty non smoking volunteers (15 woman, 16 men)
- Age: mean 24.5 years, range 18-35 years
- Smokers and oral or nasal snuff users were not allowed
- Before the start of the experiment, the experimenter checked that the participant fulfilled recruitment requirements: (a) was not wearing perfume, scented cosmetics, skin creams, and lotions, (b) had not eaten spicy food like garlic, and (c) was in good health and without allergies, colds, or any respiratory tract disease.

Ethical approval:

not specified

Route of exposure:

inhalation

Reason of exposure:

intentional

Exposure assessment:

measured

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- The test chamber consists of three parts: an air-quality controlled and air conditioned waiting room combined with an adjacent clean-air test chamber with an exposure hood in front of the subject’s seat. On the other side of the wall, the hood is connected to a dynamic-flow olfactometer in a chemical laboratory.
- The formaldehyde atmosphere was generated by blowing charcoal filtered air through a solution of paraformaldehyde (pretreated in 105–110 °C for 3 h) in 1 N sodium hydroxide. This atmosphere was in the dynamic-flow olfactometer diluted with charcoal filtered air in two steps: (1)first to 100 ppm (vol/vol) formaldehyde, monitored continuously with infrared analysis (Miran 80), (2) then to the 18 concentrations with the aid of steel capillaries injected into the main clean airflow (100 L/min) to the exposure hood.

TEST ATMOSPHERE
Every experimental day, the 18 hood concentrations of formaldehyde (and the blanks) were measured 12 times with a continuous flow analysis instrument (Skalar SA 90000). It is based on the acetyl acetone method and UV detection, with a lowest range setting of 0–50 ppb formaldehyde. No formaldehyde was detected in background clean air of the hood (blanks).

CONCENTRATIONS:
6.36, 10.1, 14.4, 18.1, 23.1, 31.7, 42.4, 57.4, 73.4, 101.4, 134.1, 177.7, 236.7, 316.1, 420.7, 567.0, 755.0, and 1000.0 ppb.

EXPOSURE:
- Each of the 31 participants evaluated 288 hood exposures (12×18 concentrations plus 72 blanks).
- Each participant first spent at least 30 min in the waiting room of the laboratory
- The participant took one sniff of less than 3 s in the hood.
- The face (nose with closed mouth) was then moved inside a teflon-sheet opening of the front of the exposure hood (teflon-coated).
- During the interexposure intervals (in-between sniffs), the subject’s head was withdrawn from the hood for her/him to be able to breathe the clean air of the test chamber (red signal in hood).
- Presentation orders were random with 36 formaldehyde presentations in each of eight 12-min sessions (3 sniffs per minute).

Examinations:

- ability to detect odor and/or sensory irritation and clean air was determined.
- For every hood presentation (odorous irritant or blanks), the participant evaluated his/her sniff and responded with one of four forced-choice response alternatives
(1) yesyes: an odor was detected accompanied with a sensory irritation detection,
(2) yes-no: an odor was detected but not a sensory irritation,
(3) no-yes: an odor was not detected, but a sensory irritation was.
(4) no-no: neither an odor nor a sensory irritation was detected.

For each of the 31 subjects in the formaldehyde experiments, the absolute thresholds at P50, and the interquartile (P75–P25) range were determined.

Results and discussion

Results of examinations:

- P50 absolute thresholds were for formaldehyde odor 110 ppb (range 23–505).
- For sensory irritation the P50 could not be calculated because too few subjects were studied and the exposure was limited to 1000 ppb. However, all thresholds for irritation were higher than for odor.