Monitoring method for inhalation exposure to gas oil vapour and aerosol

Sampling and analysis methods for the measurement of the personal workplace exposure concentration of gas oil vapors and aerosols were studied. Two sampling methods for the total concentration of gas oil atmospheres and aerosol-vapor partitioning were investigated in a laboratory set-up, i.e., a filter and XAD adsorbent cartridge operated in series (BIA-method) and a virtual-impactor combined with filter-XAD cartridges (VI-method). The BIA method allowed for sampling and measuring the total concentration of the gas oil atmospheres for concentrations > 0.5 mg/cu m for 8-hr sampling. When using the VI-method, losses between 15 and 30 % were encountered when measuring the total concentration. Evaporation effects caused a shift of the aerosol-vapor partitioning towards the vapor phase in the BIA sampling system. In the VI-method the aerosol-vapor fraction was nearly independent of the thermodynamic conditions and the sampling time. However, the partitioning coefficient can be influenced by small aerosol particles with diameters smaller than the critical cutoff diameter; this aerosol fraction is falsely counted as vapor phase.