Research in the Atmospheric Sciences Division at Brookhaven National Laboratory (BNL) has resulted in the development of a new analytical instrument capable of measuring aerosol size distribution with high time and size resolution. Aerosols refer to particles, including solids, liquids and mixtures of such suspended in a gas, such as the atmosphere.
The aerosol mobility size (AMS) spectrometer eloquently addresses the need to increase measurement speed by integrating the classification, detection and counting of aerosol particles.
Using the AMS spectrometer, aerosol particle size data can be produced in about 1 second, an improvement by a factor of 50 over current technologies such as scanning mobility particle sizers, which must scan data of individual sizes of aerosols over a range of voltages. Further, the AMS spectrometer improves upon optical particle counters, which use light scattering and have a lower signal-to-noise ratio than the AMS spectrometer.
Essentially, the AMS spectrometer separates charged particles in an aerosol flow stream based on their electrical mobility into different trajectories of size-ordered aerosol flow streams upon application of a uniform electric field. The apparatus has an improved counting rate over current technologies, while it can also detect particles smaller than 100 nm in diameter. Particle sizes in the submicron size range often dominate the number concentrations of atmospheric aerosols.
The ability to quickly capture transient aerosol dynamics occurring on very small time scales, such as in high-temperature environments or other nucleationdominated systems is a desired need for a variety of fields. Recent research has clearly demonstrated the significance of atmospheric aerosols on climate and air quality over regional and global scales. In addition, the Intergovernmental Panel on Climate Change (IPCC) asserts that the effects of aerosols are the most uncertain components in the climate system. In addition, the study of aerosol particle size distribution is related to research on the penetration of aerosol into bronchial airways and the associated health effects (e.g., for environmental pollutant release studies, or inhalant research in the pharmaceutical field or in medical devices generally).
Thus, aerosol size distribution measurement is an important analytical tool for a broad range of fields from atmospheric science and combustion systems to medical and pharmaceutical applications of aerosols.
