Related Experiment Video
Updated: Feb 12, 2026
10:44
Comparing the Effects of Electronic Cigarette Vapor and Cigarette Smoke in a Novel In Vivo Exposure System
Published on: May 24, 2017
12.2K
Sensor-triggered sampling to determine instantaneous airborne vapor exposure concentrations
Philip A Smith1, Michael K Simmons1, Phillip Toone1
1a U.S. Department of Labor - OSHA, Directorate of Technical Support and Emergency Management, Salt Lake Technical Center , Industrial Hygiene Chemistry Division , Sandy , Utah.
Journal of Occupational and Environmental Hygiene
|March 28, 2018
Summary
Measuring airborne exposure peaks is challenging. This study introduces a sensor-triggered whole-air sampling method for accurate peak concentration measurement of organic chemical vapors, improving exposure assessment reliability.
Area of Science:
- Occupational Health and Safety
- Environmental Monitoring
- Analytical Chemistry
Background:
- Integrated sampling methods struggle to accurately capture transient airborne exposure peaks for organic chemical vapors.
- Short-duration time-weighted average (TWA) values often fail to represent actual peak concentrations during rapid fluctuations.
- While laboratory analysis offers certainty, real-time sensors are crucial for measuring intra-exposure concentration variations.
Purpose of the Study:
- To develop and validate a method for accurately measuring peak airborne concentrations of organic chemical vapors.
- To assess the reliability of sensor-triggered whole-air sampling for capturing transient exposure events.
- To provide a means for verifying sensor performance during exposure monitoring.
Main Methods:
- A photoionization detector (PID) sensor was used to trigger the collection of whole-air samples when specific vapor levels (toluene or trichloroethylene) were reached.
- Whole-air samples were collected in canisters under varying relative humidity (37% and 80%) and analyzed using gas chromatography-mass spectrometry (GC-MS).
- Storage stability, precision, and bias of the collected samples were evaluated.
Main Results:
- The sensor-triggered sampling method demonstrated good agreement between collected sample concentrations and the pre-determined triggering set points.
- Whole-air samples stored at 80% relative humidity showed acceptable recovery over 17 days.
- The method successfully determined exceedances of peak exposure standards and provided a calibration point for sensor verification.
Conclusions:
- Sensor-triggered whole-air sampling provides accurate measurement of peak airborne concentrations for organic chemical vapors.
- This approach enhances the reliability of exposure assessment by combining real-time detection with precise laboratory analysis.
- The method improves confidence in sensor data accuracy throughout an entire exposure period.
More Related Videos
05:12Chronic Intermittent Ethanol Vapor Exposure Paired with Two-Bottle Choice to Model Alcohol Use Disorder
Published on: June 23, 2023
1.6K
09:29An Air-liquid Interface Bronchial Epithelial Model for Realistic, Repeated Inhalation Exposure to Airborne Particles for Toxicity Testing
Published on: May 13, 2020
12.6K
Related Concept Videos
01:18Vaporization
38.3K
The physical form of a substance changes by changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. For vaporization to occur, kinetic energy must be greater than the intermolecular forces that keep molecules bonded. The amount of energy needed to vaporize a quantity of liquid at a given pressure and a constant temperature is called the heat of vaporization. When...
38.3K
02:34Vapor Pressure
41.1K
When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules move randomly about, they will occasionally collide with the surface of the condensed phase, and in some cases, these collisions will result in the molecules re-entering the condensed phase. The change from the gas phase to the liquid is called condensation. When the rate of condensation becomes equal to the rate of vaporization, neither the amount of the liquid nor the amount of the vapor...
41.1K
03:28Vapor Pressure Lowering
31.4K
The equilibrium vapor pressure of a liquid is the pressure exerted by its gaseous phase when vaporization and condensation are occurring at equal rates:
31.4K
01:10Instantaneous Velocity - II
13.4K
Instantaneous velocity is the quantity that measures how fast an object is moving along its path. In other words, the instantaneous velocity of an object is the limit of the average velocity as the elapsed time approaches zero, or the derivative of displacement with respect to time. Like average velocity, the instantaneous velocity is a vector with the dimensions of length per unit time. Instantaneous velocity can have both positive and negative values. The instantaneous velocity can be...
13.4K
01:16Instantaneous Acceleration
23.3K
Acceleration is in the direction of the change in velocity, but it is not always in the direction of motion. When an object slows down, its acceleration is opposite to the direction of its motion. Although commonly referred to as deceleration, this causes confusion in our analysis as deceleration is not a vector, and does not point to a specific direction with respect to a coordinate system. Therefore, the term deceleration is not used. For example, when a subway train slows down, it...
23.3K
01:22Instantaneous Power
935
Instantaneous power is important in electrical circuits, mainly when dealing with sinusoidal input. Instantaneous power, denoted as p(t), results from the multiplication of the instantaneous voltage (v(t)) across an element and the instantaneous current (i(t)) flowing through it. This relationship adheres to the passive sign convention and represents a fundamental principle in electrical engineering.
935