Occupational exposure to airborne formaldehyde in hospital: setting an automatic sampling system, comparing different monitoring methods and applying them to assess exposure.

backgroundIn recent years, under-vacuum sealing (UVS) and containers with formalin encapsulated in the lid have been proposed for the reduction of occupational exposure to airborne formaldehyde (FA) in healthcare environments.

objectivesWe are presenting a study focused on the assessment of FA in hospitals: an automatic sampling system was set, different sampling devices were compared, and the concentration of FA was assessed, following its use in different scenarios.

methodsThree different devices for sampling/measuring FA were compared. They are based on: 1. silica gel cartridges impregnated with 2,4-dinitrophenylhydrazine (2,4-DNPH); 2. SPME® fiber using O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine; 3. direct reading commercial instrumentation. Three typical scenarios using FA were investigated: operating theatres where small biopsies are soaked into closed-circuit system 4% FA containers, secretariat of pathology laboratories during the registration of biopsies and pathology laboratories during the filling procedure by UVS and the slicing of biopsies.

resultsThe automatic sampling system allowed short-, long-, and in continuous-sampling time to measure airborne FA. Different sampling devices provided comparable results when tested to assess FA concentration ranging from 0.020-0.320 ppm in a test chamber, although  the devices based on 2,4-DNPH were  the best in terms of sensitivity and accuracy. The results of 246 samples showed that the FA concentration was less than 0.04 ppm in 91% of the measurements.

conclusionsThe automatic methods efficiently allow sampling and measurement of FA in hospital settings. When using safe practices, the concentration of FA is well below occupational limit values.