case studies

California Measurements instruments have been used for diverse applications in laboratories and at unique onsite locations all over the world. Our samplers are portable and rugged with an excellent track record of reliability for use in the field. Learn more about specific case studies and how results were achieved.

Atmospheric Aerosol Research

Our PC-2H Quartz Crystal Microbalance (QCM) multistage real-time cascade impactor and Microanalysis Particle Samplers have helped scientists worldwide to study particles in the upper atmospheres in all corners of the earth, over volcanoes, oceans, the Arctic and Antarctica regions.

Whether it is for measuring the mass concentration and size distribution of particles in the atmosphere over an active volcano, or for studying the spatial particle profile over a power plant, scientists have for many years used our NASA-developed PC-2H family of QCM impactors to get the data for their research. The PC-2H is a 2 lpm flow 10-stage QCM real-time cascade impactor system which utilizes well-established inertial impaction principles to separate and collect particles, covering a range of 10 to 0.05 microns in ten size fractions. It also incorporates NASA-developed QCM mass sensors in the impactor stages to “weigh” in situ the amount of particles collected in each size group and provide mass concentration and size distribution data automatically.

Moreover, the particle samples collected on the small (0.5 in. dia.) quartz substrates in the impactor stages can be retained and brought back to the laboratory for detailed analysis. Information on the particles’ morphology and physical or chemical make-up can be determined using advanced microanalytical techniques, such as scanning electron microscopy and energy dispersive X-ray spectroscopy. With this additional information, in addition to the concentration and size distribution data, the researcher is able to get the full story on the aerosols in the atmosphere.

Various versions of the instrument have seen service on many types of research aircraft over a span of many years. NASA has mounted it in their high-altitude U-2 and ER-2 to sample and measure particles in the upper atmospheres. NASA in conjunction with other U.S. government agencies has flown its instrument on a helicopter over oil fires in Kuwait after the first Gulf War to study the smoke plumes over the sites. Smaller and lightweight versions of the instrument have also operated on other types of platforms, such as Remote Piloted Vehicles (RPVs) and balloons.

In addition to the above, scientists have also used with great success our Microanalysis Particle Samplers, also multistage inertial impactors, to collect size-segregated particle samples for microanalysis in a scanning electron microscope (SEM). This instrument has the unique feature of using a standard scanning electron microscope (SEM) sampler holder in each impactor stage to collect samples on its substrate. The holder, with samples on it undisturbed, is later inserted directly into the SEM for immediate particle analysis with minimal or no sample preparation. It also allows particles to be collected directly onto Transmission Electron Microscope (TEM) grids to allow direct TEM post-sampling analysis without having to first collect samples on one substrate and then transferring them onto a TEM grid, a very laborious process.