The Ultraviolet Aerodynamic Particle Sizer (UV-APS) Model 3314 by TSI Instruments is a multifaceted spectrometer. With the ability to conduct measurements of scattered light intensity, fluorescence and aerodynamic size in real time, this platform provides comprehensive profiling of aerosol characteristics. The system features two innovative methods of detection for conducting these three measurements techniques. For determining the diameter (and thus the size) of aerosol particles, a double crest optical system is employed. This same technology is also utilized for measuring scattered light intensity, and is proven to offer both precision and reliability in providing results. For conducting fluorescence measurement, a pulsed UV laser excites particles while data is collected in real time by a photomultiplier tube (PMT). In this way, biological aerosol particles can be distinguished from inanimate substances. The characterization spectrum for airborne particles is 0.5 um up to 20 um (based on PSL calibration), and fluorescence intensity can be measured simultaneously with the other two methods (aerodynamic diameter and scattered light intensity).
Two overlapping red laser beams conjoin to produce a single, double crested time of flight signal for each particle as it is accelerated and subsequently ejected from a nozzle. The time differential between these crests is used to determine the aerodynamic size of the particle. Scattered light intensity is measured via avalanche photodetector. A secondary benefit of the overlapping beam technology is that, unlike systems which rely on two individual pulses, the UV-APS can identify false signals such as coincidence and therefore optimize accuracy while minimizing background noise. For fluorescence intensity measurements, time of flight is used to coordinate the arrival of a particle at the detection site. These particles can then be excited, with detection occurring for any fluorescence between 430 nm and 580 nm.
System resolution for the three measurement techniques are as follows: up to 52 channels for aerodynamic size, up to 64 channels for fluorescence intensity, and up to 64 channels for scattered light intensity. Maximum particle concentration is 1500 particles per cubic centimeter and 600 particles per cubic centimeter for 0.5 um and 10.0 um particles, respectively. Particle size intervals are 16 channels per decade of particle size (logarithmic) for aerodynamic measurements. Laser sources are a 680 nm (30mW) red diode laser and a 355 nm (80mW) pulsed UV laser.
With the ability to perform three measurement techniques in a single instrument, the versatile platform is ideal for applications such as biohazard detection, drug delivery studies, air quality monitoring (indoor) inhalation toxicology research, ambient air monitoring, biological aerosol investigations, and a variety of other biological studies.