Personal exposure to formaldehyde

Dingle, Peter Wayne (1995) Personal exposure to formaldehyde. PhD thesis, Murdoch University.

Abstract

The primary objective of this research was to investigate exposure to formaldehyde. There has been very little research on personal exposure to pollutants in the community and none on personal exposure to formaldehyde. In Australia, there are very little data on indoor formaldehyde concentrations. This is despite the fact that in Europe and in the United States, formaldehyde is one of the most frequently found indoor air contaminants, and is known to cause both acute and chronic health effects.

The results of this research generally support the hypothesis that fixed site monitoring in indoor environments is able to explain a substantial portion of the personal exposure to formaldehyde. However, the study also provided results in cabinet making factories which are not consistent with this hypothesis. The results did not support the hypothesis that time weighted models will improve the accuracy of personal exposure predictions relative to linear regression models of indoor and outdoor concentrations.

The research was divided into two areas. Firstly, the spatial and temporal changes in concentrations of formaldehyde in indoor environments, and the factors affecting these levels were investigated. This resulted in a comprehensive documentation of the concentrations found in typical indoor environments, and in indoor environments likely to experience elevated concentrations of formaldehyde. Secondly, an assessment of personal exposure to formaldehyde, and a comparison of these results to formaldehyde concentrations recorded at fixed sites was conducted. This enabled the comparison of different models to understand personal exposure.

Formaldehyde exposure assessment was conducted in 186 Australian homes and 60 occupied caravans and indoor measurements recorded in 132 unoccupied caravans. There were no significant differences between levels recorded in winter or summer for conventional homes monitored during different seasons, however a significant seasonal difference occurred in concentrations recorded in caravans. The highest concentrations were recorded in winter. In conventional homes a significant decrease in formaldehyde concentrations was found in levels recorded 6 months after the initial monitoring. The decrease was greatest in homes less than 10 years of age. In 13 multi-storey office buildings, levels ranged from 4 ppb to 90 ppb, with the highest concentrations being recorded in new buildings. A new four floor building was assessed for formaldehyde over fourteen months. Formaldehyde concentrations increased as the building progressed through its construction phase, and with the introduction of furnishings and carpet. After occupation, fluctuations in formaldehyde concentrations in the building were closely correlated with outdoor temperatures.

The results from 24 hour personal exposure of people, non-occupationally exposed to formaldehyde, in conventional homes and caravans suggest that the home environment is the most important predictor of formaldehyde exposure. Measurements in conventional homes were able to account for between 54% and 61% of the variation of personal exposure. Measurements in caravans were able to account for 71% of the variation in personal exposure.

For people occupationally exposed to elevated concentrations of formaldehyde, personal exposure in the workplace is the most significant exposure in accounting for variation in 24 hour personal exposure. Time weighted models were not found to improve the explanation of variation in personal exposure.

This research derived models of formaldehyde exposure for people occupationally exposed to formaldehyde and identified concentrations in the home as the major determinant of personal exposure to people nonoccupationally exposed to formaldehyde. It also highlighted the complexity of personal exposure and the need to use time weighted models with some caution. The next step in research should be aimed at expanding these tests with different population sub-groups and the use of real time personal monitoring when the equipment is developed. This would facilitate a more complete description of personal exposure to formaldehyde and more accurate exposure models to assess the potential impact of formaldehyde on public health.

Item Type:	Thesis (PhD)
Murdoch Affiliation(s):	School of Biological and Environmental Sciences
Notes:	Note to the author: If you would like to make your thesis openly available on Murdoch University Library's Research Repository, please contact: repository@murdoch.edu.au. Thank you.
Supervisor(s):	Murray, Frank
URI:	http://researchrepository.murdoch.edu.au/id/eprint/51327

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