Determining chemical air equivalency using silicone personal monitors.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Exposure Science

Background:

• Silicone personal samplers are increasingly used for chemical exposure assessment.
• Many studies using these samplers do not calculate environmental concentrations.

Purpose of the Study:

• Develop predictive models for silicone-air partition coefficients (log Ksa) and uptake rate constants (ke).
• Enable air equivalency calculations for volatile and semi-volatile organic compounds using silicone wristband data.

Main Methods:

• Used an atmospheric vapor generator and exposure chamber to measure chemical uptake into silicone wristbands.
• Developed and validated log Ksa predictive models using empirical data and k-fold cross-validation.
• Compared air equivalency between different predictive models.

Main Results:

• Predictive models for log Ksa and log ke were built using boiling point and other parameters (R² = 0.70-0.94).
• Refined log Ksa models, combined with published data, achieved high predictive accuracy (R² = 0.95-0.97).
• Novel models demonstrated strong correlation for air equivalency estimations across a wide concentration range (Spearman r = 0.984).

Conclusions:

• Silicone sampler data can be translated into air equivalent concentrations.
• This translation aids in characterizing environmental concentrations related to personal exposures.
• Provides a method for direct comparison of exposure data to regulatory standards.