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Toxicological information

Sensitisation data (human)

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Administrative data

Endpoint:
sensitisation data (humans)
Type of information:
other: Review
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
Remarks:
Comprehensive scientific review. Reviewed data as well as the review itself published in peer reviewed journals.

Data source

Reference
Reference Type:
review article or handbook
Title:
Non-cancer effects of formaldehyde and relevance for setting an indoor air guideline
Author:
Wolkoff P., Nielsen G.D.,
Year:
2010
Bibliographic source:
Environment International 36 (2010) 788–799

Materials and methods

Type of sensitisation studied:
respiratory
Study type:
other: review of existing data
Principles of method if other than guideline:
Existing literature is reviewed on formaldehyde (FA) exposure with focus on chemosensory perception in the airways and lung effects in indoor environments.
GLP compliance:
no

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 (FA)

Method

Details on study design:
- The term formaldehyde was searched from 1995 and up to the present, and in combination with: allergy, asthma(tics), airway (irritation), bronchoconstriction, children, eye (irritation), emission, inflammation, homes, IgE, (nasal) irritation, kindergartens, lung effects, lung function, offices, odour, schools, sensory irritation, sickbuilding syndrome, sensitization, and trigeminal stimulation.
- In addition to databases, such as PubMed and Google Scholar, recent comprehensive reviews were also considered (including Health Canada, and international reports)

Results and discussion

Results of examinations:
Authors concluded that exposure of asthmatics to formaldehyde would not lead to an exacerbation of the lung function.
Also, theyoncluded that at exposures <100 ppb such associations between children and adults in homes and schools have generally not been convincing mainly due confounding factors and susceptibility of the findings to chance effects.
Furthermore, they did not identify major differences between children, adults, and asthmatic

Any other information on results incl. tables

Sources and soncentrations

- The main source of FA is emission from building and furnishing materials, notably wood and wood-based products. Other products that release FA include those with fungicides, paints, consumer products, cosmetics, electrical equipment, and tobacco. Reported mean indoor concentrations of FA generally lie in the range of 0.005 to 0.1 mg/m3 with some higher concentrations in new or renovated housing, e.g. A number of European projects reported mean exposure concentrations in homes (sampling time: 1–7 days), generally as less than 0.05 mg/m3. Concentrations of FA measured in public buildings in Europe generally lie below those measured in homes (0.025 mg/m3). Outdoor concentrations fall below 0.01 mg/m3 in European cities.

Metabolism, distribution in the body, and retention in the nasal cavity

- The metabolism of FA is so fast that 0.5 mg/m3 exposure does not increase urinary formate excretion; further, FA does not accumulate in the blood after intravenous administration to animals (cats, dogs, and monkeys). It appears unlikely that inhaled FA reaches internal organs after portal of entry. Retention of FA in the moist layers covering the nasal mucosa, i.e. regions of the upper respiratory tract, exceeds 90–95% in rodents and primates owing to its high solubility in water and reactivity.

Chemosensory perception/sensory irritation

- A large variety of odour thresholds has been reported for FA from 0.05 to 0.5 mg/m3. It is considered, that a significant fraction of the population perceives FA at or below 0.1 mg/m3 without interfering background. Formaldehyde stimulates not only to the sense of smell, but also the chemesthetic sense, i.e., the capacity to feel chemicals. Humans exposed to the vapour have long noted eye and nasal irritation. Such responses occur principally via stimulation of the trigeminal nerve. Formaldehyde has a detectable odour at all the concentrations of interest for chemesthesis. Thus, the odour interferes with judgment of those concentrations, i.e. difficulty of separating the integrated input of the odour and sensory irritation.

Threshold for sensory irritation:

- In general, the eyes are considered to be more sensitive to chemesthesis than the upper airways. Threshold values for sensory irritation have been suggested from 0.25– 0.35 mg/m3 to 1.2 mg/m3.

Human exposure studies:

- The exposure of asthmatics to FA and grass pollen or dust mites at indoor air concentrations does not indicate exacerbation of the lung function.

Epidemiological studies in children and adults:

- After a detailed analysis of the conflicting results reported by Ezratty et al 2007 and Casset et al 2006 the authors concluded that exposure of asthmatics to formaldehyde would not lead to an exacerbation of the lung function. They also reviewed case control and cross sectional studies that had suggested a possible association of low formaldehyde concentrations and asthma. By taking into consideration the complex exposure situations and potential confounding factors, they concluded that at exposures <100 ppb such associations between children and adults in homes and schools have generally not been convincing mainly due confounding factors and susceptibility of the findings to chance effects. Furthermore, they did not identify major differences between children, adults, and asthmatic.

Applicant's summary and conclusion