A low-cost particle counter as a realtime fine-particle mass monitor

Abstract

Exposure to particles with aerodynamic diameters less than 2.5 μm is estimated to cause significant morbidity and mortality worldwide leading many countries to develop ambient air pollution standards and guidelines. At local scales, community and environmental justice groups are also concerned about PM 2.5 concentrations that may be elevated above regional concentrations typically measured by centrally located monitors and standards as well. In an attempt to develop a low cost, easy to use monitor we evaluated a low-cost optical particle counter, the Dylos™, as a fine particulate mass sensor. Modified into a system called the Berkeley Aerosol Information Recording System (BAIRS), we compared performance against standard commercial instruments in chambers using polystyrene latex spheres, ammonium sulphate, and woodsmoke and in an urban ambient setting. Overall we find that the limit of detection of the BAIRS is less than 1 μg m (-3) and the resolution is better than 1 μg m(-3) for PM 2.5. The BAIRS sizes small (<0.5 μm) particles, and is able to accurately estimate the mass concentration of particles of varying composition including organic, inorganic, and ambient particles. It is able to measure concentrations up to 10.0 mg m (-3). In an ambient roof-top test of the BAIRS and a more expensive commercially available light scattering particle monitor the BAIRS response tracked well with the commercial monitor and daily means were within 80% of each other. We conclude that with appropriate modification the system could be developed into an accurate low cost realtime particle mass monitor for use in a wide range of applications.

Personal exposure monitoring of PM 2.5 in indoor and outdoor microenvironments

“…The Dylos has been used and evaluated in other studies, both indoors and outdoors, e.g. by Semple et al (2012Semple et al ( , 2013, in the context of exposure to SHS, and by Northcross et al (2013) and Holstius et al (2014) who compared the performance of the Dylos against other commercially-available particle monitors (both for chamber and ambient environments).…”

Handheld personal airborne nanoparticle detector based on microelectromechanical silicon resonant cantilever

“…Fully integrated (i.e., miniaturized electronic circuitries, microfilter, impactor, PLL, and LCD), compact, handheld, lowcost (<200 €, at a total quantity of 100), easy to use, batteryoperated Dylos Corp., USA [23] Scattering of laser light $400 g, < 1 lg/m 3 , realtime Particle diameter > 0.5 lm, price < $300…”

“…Moreover, the particles detected by the devices from McGill University, DU, and BSAC were microparticles. Besides MEMS-based NP mass sensors, portable non-MEMS-based particle monitoring instruments are also available with different sensing mechanisms (i.e., Dylos Corp., USA [23] with scattering of laser light and Naneos Particle Solution GmbH, Switzerland [8] with charging of particles and charge measurement using electrometer). Electrophoretic precipitator and self-exciting and self-sensing in-plane silicon cantilever resonator (CANTOR-2) 375 g, 5 lg/m 3 , 6 s…”

“…Correspondingly, a paradigm shift has been addressed in air pollution monitoring toward lower-cost, easy-to-use, portable, and direct-reading sensors [22]. A step in this direction is the Dylos Air Quality Monitor, which costs less than $300 and is found to track well with standard commercial monitors [23]. However, since it is based on light scattering, it is limited to the particle diameter range above of 0.5 lm.…”

Enhanced performance of pocket-sized nanoparticle exposure monitor for healthy indoor environment

“…Correspondingly, production of a second commercial DC (Nanotracer, Philips, Netherlands) was stopped in 2012 [6]. A low-cost optical particle counter (OPC) based on the commercial Dylos Air Quality Monitor, which is available at < $300, is based on optical scattering (650 nm), i.e., NPs with diameters of less than 300 nm cannot be detected [7]. Furthermore, calculation of mass concentrations c m from measured NP number concentrations requires knowledge on their shape and density.…”