China
Africa
Explore chapters and articles related to this topic
Total Particle Counts
Published in James Agalloco, Phil DeSantis, Anthony Grilli, Anthony Pavell, Handbook of Validation in Pharmaceutical Processes, 2021
The particle counter measures the amount of light scattered by a particle and places the relative size of the particle in a “size bin.” A size bin is determined from the boundary thresholds. If a particle counter has several channels, such as a 0.1 μm sensitive instrument, the first channel on the display is shown as 0.1 microns. The second channel is shown as 0.2 microns. The third channel is shown as 0.3 microns. If a particle falls in the first channel, it is sized as being between 0.1 micron and 0.2 micron. It may be as small as 0.105 micron or as large as 0.195 micron but still falls in the first channel.
Usp 23 <788> Particulate Matter in Injections
Published in Thomas A. Barber, Control of Particulate Matter Contamination in Healthcare Manufacturing, 1999
The particle size resolution of the instrumental particle counter is dependent upon the sensor used and may vary with individual sensors of the same model. Determine the resolution of the particle counter for 10-μm particles using the monosized 10-μm calibrator spheres. The relative standard deviation of the size distribution of the standard particles used is not more than 5%.
Efficacy of aerosol reduction measures for dental aerosol generating procedures
Published in Aerosol Science and Technology, 2022
Zixin He, Qiman Gao, Anna Henley, Zovinar Der Khatchadourian, Wendy Somerville, Michael Wiseman, Luc Mongeau, Faleh Tamimi
While an optical particle counter is highly sensitive to the presence of particles within its range of measurement, it can only measure the particle size and cannot distinguish between different sources of aerosol. The particle counter also cannot assess the particle mass nor surface area, which are characteristics that greatly impact the particle’s aerodynamic properties and its ability to carry pathogens. There are a number of contributing factors to an increase in aerosol concentration, such as the operators, the air pollution, dust, etc. Since the particle counter cannot discriminate particles by source, it becomes imperative to eliminate and isolate aerosol sources external to the experiment. Hence, strategies such as the closing of doors, the stoppage of the ventilation system, the usage of PPE by operators, and the air renewal between each measurement, were used in the present study.
Determining the cutoff diameter and counting efficiency of optical particle counters with an aerodynamic aerosol classifier and an inkjet aerosol generator
Published in Aerosol Science and Technology, 2020
Steven Tran, Kenjiro Iida, Kumiko Yashiro, Yoshiko Murashima, Hiromu Sakurai, Jason S. Olfert
Optical particle counters (OPC) are commonly used for cleanroom monitoring, air pollution studies and aerosol research. An optical particle counter is an instrument that can measure the size and concentration of small particles suspended in a gas based on the light scattered by the particle (Sorensen et al. 2011). An optical particle counter operates by drawing an aerosol sample through a beam of light, the light scattered by the particle is received by a photodetector and converted into an electrical pulse. The number concentration of the particles in the aerosol is determined by the number of the pulses and sampled volume, and the size of the particle can be determined from the pulse height. This method of particle sizing has been known for more than 50years with improvements in the technology being steadily developed over time; moving from white light and incandescent bulbs to lasers as the light source (Sorensen et al. 2011).
Evaluation of PM1, PM2.5, and PM10 exposure and the resultant health risk of preschool children and their caregivers
Published in Journal of Environmental Science and Health, Part A, 2019
Kuo-Pin Yu, Yu-Cheng Lee, Yen-Chi Chen, Jia-You Gong, Ming-Hsuan Tsai
In this study, we used two laser airborne particle counters (Lighthouse Handheld 3016-IAQ) to simultaneously monitor PM concentrations at different heights. The particle counter offers six particle size channels (i.e., 0.3, 0.5, 1, 2.5, 5, and 10 μm), and the counting efficiency of the particle counter is 50% for 0.3-µm particles and 100% for particles larger than 0.45 µm. This particle counter operates at a sampling flow rate of 2.83 liters per minute (Lpm) and has an isokinetic sampling probe. The output data include particle number concentration, mass concentration (with an assumed particle density of 2.5 g cm−3), relative humidity and temperature. The measured mass concentration was adjusted by a factor of 0.68 according to the previously reported particle density of ambient airborne PM (approximately 1.7 g cm−3).[21,22] The instrument records one measurement per minute, and 120 data points were recorded at each sampling site. The particle counter was calibrated every six months. During sampling, the particle counters were set at heights of 150 cm (to represent the exposure of adults) and 60–80 cm (to represent the exposure of children), according to the Compilation of Exposure Factors in the Taiwan General Population.[23]