Interzonal airflow rates for use in near-field far-field workplace concentration modeling
| Autor: | Yuxi Zhao, Chris Keil |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Air Movements
Meteorology Indoor air Chemistry Airflow Public Health Environmental and Occupational Health Mixing (process engineering) Near and far field Air Pollutants Occupational Photoionization Mechanics Models Theoretical 010501 environmental sciences Table (information) 030210 environmental & occupational health 01 natural sciences Ventilation Acetone 03 medical and health sciences 0302 clinical medicine Volume (thermodynamics) Workplace Environmental Monitoring 0105 earth and related environmental sciences |
| DOI: | 10.6084/m9.figshare.5105074.v1 |
| Popis: | Interzonal air flow rates (β) for a workspace above a table were measured in 12 indoor air spaces using an experimental apparatus simulating a vapor release into an occupied near zone. The near field was modeled as a 0.32 m3 rectangular cube volume 0.60 m high above the 0.60 m × 0.90 m table. A total of 74 experimental measurements of β were made. The apparatus consisted of photoionization detectors measuring concentrations of acetone around an evaporating liquid surface with a robot arm simulating worker motion in the near field. The vapor release rate and the resulting concentrations were used in a near-field far-field (NF-FF) model to calculate β. Measures of mixing within the near-field supported the assumption of the NF-FF model that the near field is well-mixed. Measured values of β ranged from 0.4–19 m3/min with an average of 4.8 m3/min. This corresponds to 1.2–59 air changes per minute in the near field and an average of 15 air changes per minute. The values of β were log normally distributed with a geometric mean of 3.4 m3/min and a geometric standard deviation of 2.3. The 95% confidence interval on the geometric mean of β was 2.8–4.2 m3/min. The product of the random air speed in the room and one half of the near-field free surface area was shown to be a good method of determining β. There was a slight correlation seen between room volume and β, but the effect size was small. Room air change rate was not found to be correlated with β. The observed distribution of β will be helpful in selecting values for interzonal airflow rate in NF-FF modeling of worker exposures. |
| Databáze: | OpenAIRE |
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