Impact of PAH compounds in building materials on indoor air quality - PAHSIS
In Finland, hazardous waste limit values for PAH(16) compounds are commonly used to assess the hazards of PAH-containing building materials. However, these limit values are not suitable for assessing the usability of buildings or determining the need for and methods of repair. The current over-estimation of the risks of PAH compounds has led to a “demolish everything” approach and, as it expands, it can have a significant economic impact. The results obtained in this study provide a more reliable model for assessing the risks related to repair needs.
A previous study has shown that the emissions of PAH compounds in building materials vary between types of building materials. This study investigates the actual emissions of PAH compounds in different types of building materials and their impact on indoor air quality by experimental and computational methods. This information can be used to estimate the actual indoor air risk and the need for repairs or demolition.
A perceived odour nuisance in a place with a PAH problem is not expected to correlate with actual health risks, but at the same time it does affect well-being at work. Odour thresholds for PAH compounds are low and concentrations of as little as 2 µg/m3 are generally detectable. However, this concentration does not cause any adverse health effects, even at full-time exposure. However, the link between the perceived risk and the actual risk and the impact of the perceived risk on well-being at work have not been investigated. The odour threshold values are also not up to date.
Concentrations presenting a real health risk are assumed to be disproportionate to the measured concentrations of PAH compounds. Researched data will help to reduce concerns about indoor air quality. Determining the odour thresholds and comparing them with the perceived odour nuisance in problem areas gives a numerical and easily understandable value instead of a sensory assessment. The odour threshold results can also be utilized in legislation when updating the limit values.
Materials and techniques
For the purpose of the study, the following data will be collected from the actual target buildings.
Samples of intact building materials collected from old buildings:
Construction papers and paperboard, wood products, membrane-like products
Material surfaces to be inspected on site:
- Coating products and mastic asphalt surfaces
The concentrations of the PAH(16+2) compound and individual PAH compounds (µg/m3) under normal conditions shall be measured in the indoor air of all spaces studied.
The concentrations of the PAH(16+2) compound (mg/kg) and individual PAH compounds shall be investigated in all samples studied.
The treated surfaces of the samples shall be made free of emissions, and any emissions [µg/m2h] from intact surfaces shall be measured in a FIOH laboratory using surface emission and emission chamber techniques.
The results are modelled using a mixing equation. The theoretical indoor air PAH compound concentrations can be determined from the mixing equation when the production of PAH compounds and the air change rate are known.
The assessment of the users of the space about the indoor air quality of the space and part/floor/area of the building to be surveyed, including odour observations, are collected with a survey.
The odour threshold (naphthalene, 1- and 2-methylnaphthalenes and phenanthrene) is determined with an odour panel (women and men, two age ranges, a total of four panels) at the Finnish Institute of Occupational Health. The gas mixtures of the compounds are produced by certified permeation tubes in a calibration gas generator.
Project manager, research manager
The Finnish Work Environment Fund, Vahanen Group, Finnish Institute of Occupational Health