Models for nearly every occasion: Part III - One box decreasing emission models.

Area of Science:

• Environmental Health Engineering
• Occupational Safety and Health
• Indoor Air Quality

Background:

• Existing models often lack the granularity to accurately assess complex ventilation strategies.
• Understanding chemical emission dynamics is crucial for effective exposure control in workplaces.
• Need for adaptable models that account for various emission reduction techniques.

Purpose of the Study:

• Introduce novel "well-mixed room" decreasing emission (DE) models.
• Develop models for scenarios including local exhaust, filtered return, and filtered air recirculation.
• Provide tools for predicting both steady-state and transient chemical concentrations.

Main Methods:

• Presentation of steady-state and transient model equations for different control device scenarios.
• Development of transient equations to predict concentrations over time after substance application.
• Proposal of a structured calibration procedure using a mass balance approach to estimate model variables.

Main Results:

• Transient models accurately predict task exposure profiles, average, peak, and short-term exposures.
• Steady-state models estimate average concentrations per application and for tasks with multiple applications.
• Calibration procedure allows calculation of applied mass, local exhaust capture efficiency, and filtration efficiencies.

Conclusions:

• The new DE models offer a flexible framework for assessing ventilation control effectiveness.
• Models can be used to predict various exposure metrics, informing risk assessments.
• Proposed calibration and estimation procedures enhance the practical application of these models for emission rate constant determination.