Industrial operators know prolonged exposure to the fine dust particles generated by either construction or industrial operations can be hazardous to human health, contributing to both lung and cardiovascular disease. To prevent harmful effects on workers (and, sometimes, people in surrounding communities), operators are required to measure the concentration of airborne pollutants or particulates generated in order to ensure that the levels of pollutants stay within required concentrations. To do this, an air-quality monitoring program is required and that best meets cost and accuracy requirements.
When determining which dust-monitoring equipment or dust gauges to use, it’s helpful to consider the methods used to measure dust and which one best meets your needs. The two methods used to measure particulate matter (such as PM10, PM2.5, PM1 and TSP) are a filter-based gravimetric method and a real-time method.
Gravimetric instruments (also known as reference instruments) use a quantitative measure based on the mass of the solid. The instruments collect particles on ventilated filters. The filters then need to be processed at a laboratory to determine the concentration of the particulate or pollutant. Although the gravimetric method is typically the most accurate option, it is the costliest and requires daily or weekly manual filter weighing and lab analysis.
Real-time monitors, a.k.a. optical monitors, use the principles of light scattering or light absorption. By sensing the light reflected by a particle stream onto a photodetector, this equipment can calibrate the concentration of particulate mass. These monitors can be more affordable than gravimetric instruments, as the optical sensors they utilize less costly and can be purchased as an all-inclusive, fully-integrated station—complete with internal data-logging, communication capability and a power supply. IHW