Details
Study title
Size selective peronal air sampling using porous plastic foams
Ref study 6875
Study language English
Contributing institutions
Authors
Keywords
  • Particle size sampling
  • Polyurethane foam
  • Occupational hygiene
  • Analytical methods
  • Polycyclic aromatic hydrocarbons
  • Pesticides
  • Heavy metals
  • Foam weighing
Disciplines
Period
1997-2001
Geographical space
Country
Abstract
Porous plastic foam media like polyurethane has been shown to present good characteristics for the particle size penetration that mimic their penetration properties in the lungs. The project aims at developing a method for the simultaneous sampling on porous plastic foam filters of the three dust fractions (inhalable, thoracic and respirable). The purpose is the use a foam piece inserted in a device which constitutes in a simple, compact and low cost instrument. The outcomes would be the improvement of measurement procedures for the monitoring of workers exposure to toxic agents in the workplace atmosphere in accordance with European regulations resulting from the implementation of European standards concerning the size fractions of airborne particles to be collected. The project is a collaborative work being carried out by six European laboratories, each of them national leader in the field of occupational hygiene. We are task leader for the work packages pertaining to foam quality and analytical methods andparticipate to the steering committee. As contributions to the group, we have provided a literature review on chemical methods applied to the determination of toxic agents collected on plastic foams. We made a thorough investigation on many techniques for the determination of foam porosity in order to propose a simple and reliable procedure for future users of foam filters to check this physical characteristic. Relationships between foam diameters, thickness, flow rates and porosities were studied. The purity of the base foam materials was examined in terms of inorganic contaminants the levels of which are a few g/g of foam. Digestion procedure for the determination of trace heavy metals in foam was studied. Tentative identification was made for organic impurities coming mostly from the starting reagent materials and plasticizers. Washing and cleaning procedures were devised as well as the control of alteration risk of foam physical characteristics. Some of the experiments were conducted in collaborative studies and intercomparisons with our German partner. Another main feature of our contribution is the systematic study of the influence of relative humidity and temperature on the absorption of moisture by foam and its consequences for the weighing at constant weigh at the g level. An installation with control of RH and temperature was developed and proposed for the weighing of foam at 10 g.
Results
We continued our previous investigations on the influence of temperature and humidity on foam weight. Estimating the dependency on humidity, it is found that a change of 10% relative humidity in the range of 30 to 60% results in 0.27% weight change. The conditioning time is proposed to be 24 hours before weighing at constant relative humidity nearby 50% in non climatized rooms but in a temperature and humidity controlled glove box in order to achieve an accuracy at 10 ug for foam pieces at the 250 mg levels. Going further in other work packages, we designed a prototype of sampler based on the acquired findings from partners on penetration of various foams types, in order to test performances of analytical methods in terms of sample treatment and recovery under realistic conditions similar to that found at the workplace.
Our prototype sampler is representing an alternative to adopted samplers based on the IOM and GSP sampling heads since it makes use of the very commonly used Gelman cassettes with subsequent adaptors for holding the two size selective foam types and also devices for the sampling of gas phase or semi volatile compounds. Elements like lead and nickel were first used as test compounds for toxic metals. Digestion procedures for foam were studied and the solubilization of foam appears to be complete despite minor differences of procedures carried out in different laboratories. The levels of background elemental compounds are not to significantly interfere with the determination of trace metals. Designed procedures are under way for evaluating the performances of foam to adequately sample organic compounds in the atmosphere.
Methods (description)
Methods (instruments)
Replicated study No
Financed by


Mandating institution(s)
  • Federal Department of Home Affairs - FDHA, Bundesamt für Bildung und Wissenschaft - BBW, Hallwylstrasse 4, Postfach , 3003 Bern
Ethical approval No
Study type
Data availability
Source (Updates) Web
Date created 30.08.2013
Date modified 30.08.2013
Start - End date 01.05.1997 - 28.07.2001