Abstract. We present a portable, inexpensive, and accurate
microelectromechanical-system-based (MEMS-based) condensation particle counter
(CPC) for sensitive and precise monitoring of airborne ultrafine particles
(UFPs) at a point of interest. A MEMS-based CPC consists of two main parts:
a MEMS-based condensation chip that grows UFPs to micro-sized droplets and a
miniature optical particle counter (OPC) that counts single grown droplets
with the light scattering method. A conventional conductive cooling-type
CPC is miniaturized through MEMS technology and three-dimensional (3-D)
printing techniques; the essential elements for growing droplets are
integrated on a single glass slide. Our system is much more compact (75 mm × 130 mm × 50 mm), lightweight (205 g),
and power-efficient (2.7 W) than commercial CPCs. In quantitative
experiments, the results indicated that our system could detect UFPs with a
diameter of 12.9 nm by growing them to micro-sized (3.1 µm) droplets.
Our system measured the UFP number concentration with high accuracy (mean
difference within 4.1 %), and the number concentration range for which
our system can count single particles is 7.99–6850 cm−3. Thus,
our system has the potential to be used for UFP monitoring in various
environments (e.g., as an air filtration system, in high-precision industries
utilizing clean rooms, and in indoor and outdoor atmospheres).
Activation of sub 2 nm Water Soluble and Insoluble Standard Ions with Saturated Vapors of Butanol in a Boosted TSI Ultrafine CPC.
