Condensation particle counter

There are several different approaches that are commonly used to determine particle size distributions in air. One of them, impaction, has been discussed earlier. Multistage impactors with different cut points are used extensively to obtain both mass and chemical composition data as a function of size for particles with diameters > 0.2 /xm. Others, including methods based on optical properties, electrical or aerodynamic mobility, and diffusion speeds, are described briefly in the following section. The condensation particle counter (CPC) is used as a detector in combination with some of these size-sorting methods. 

Condensation particle counter (CPC) Very small particles in the Aitken range act as condensation nuclei for the formation of larger particles in a supersaturated... 

Note DMS differential mobility spectrometer, SMPS scanning mobility particle sizer, CPC condensation particle counter, TDMPS twin differential mobility particle sizer, DMPS differential mobility particle sizer, OPC optical particle counter, APS aerodynamic particle sizer, MAS mass aerosol spectrometer, LAS-X optical laser aerosol spectrometer, ELPI electrical low pressure impactor... 

Tuch et. al. [231] ran a Mobile Aerosol Spectrometer (0.1 to 2.5 pm) and an Electrical Aerosol Spectrometer (0.5 to 10 pm) side by side for 6 weeks and found both to be reliable with almost identical results. Total number counts agreed with results from a Condensation Particle Counter. 

Depending on the goals, a variety of procedures can be used to facilitate particle detection. In condensation particle counters (also called condensation nucleus (CN) and Aitken nucleus counters), particles as small as 3 nm diameter are detected through size enhancement and optical detection. The particles are introduced into a chamber that contains a supersaturated vapor (water or n-butyl alcohol is commonly used). Condensation on the particles enlarges them typically to several micrometers so that they can be readily detected and counted as they pass through the chamber. 

Buzorius G., RannikU., Makela J. M., Vesala T., and Kuhnala M. (1998) Vertical aerosol particle fluxes measured by eddy covariance technique using condensational particle counter. J. Aerosol Sci. 29, 157-171. 

Observations of atmospheric nanoparticle number concentrations have increased greatly during the last five years. This advance has been made possible by new instruments and techniques that can measure particles with diameters as small as 3 nm. The new approaches include pulse height analysis of data from an ultrafme condensation particle counter (UCPC) (Stolzenburg and McMurry 1991 Wiedensohler et al. 1994 Weber et al. 1998b) and the combination of a nano-differential mobility analyzer (nano-DMA) (Chen and Pui 1997 Seto et al. 1997) with a UCPC. 

TOTAL NUMBER CONCENTRATION CONDENSATION PARTICLE COUNTER... 

Figure 6.3 Schematic diagram of condensation particle counter.

The diffusion battery consists of banks of tubes, channels, or screens through which a submicron aerosol passes at a constant flow rale. Particles deposit on the surface of the battery elements, and the decay in total number concentration along the flow path i measured, usually with a condensation particle counter. The equations of convective diffusion (Chapter 3) can be solved for the rate of deposition as a function of the particle diffusion coefficient. Because the diffusion coefficient is a monotonic function of particle size (Chapter 2), the measured and theoretical deposition curves can be compared to detennine the size for a monodisperse aerosol. 

The dynamics of the total number concentration, and volume fraction of aerosol material. 0, are momenrs of special interest. There is a problem in defining the total number concentration, N, in all experimentally meaningful way. This parameter is usually measured with a condensation particle counter (CPC) (Chapter 6). The CPC detects particles larger than some minimum size that depend.s to some extent on their chemical nature and shape. Let v,i be the minimum detectable particle volume. Then... 

Seifert, M., R. Tiede, M. Schnaiter, C. Linke, O. M6hler, U. Schurath and J. Strom Operation and performance of a differential mobility particle sizer and a TSl 3010 condensation particle counter at stratospheric temperatures and pressures, J. Aerosol Sci. 35 (2004) 981 -993. 

Filter collection efficiency was evaluated by comparing filter upstream and downstream particle concentrations measured by an SMPS (Scanning Mobility Particle Sizer) consisting of a long DMA (Differential Mobility Analyzer - Model 3080) and a U-CPC (Ultrafine Condensation Particle Counter - Model 3025). The cordierite wall-flow filters exhibited their well-known soot collection efficiency while the foam sample exhibited a lower collection efficiency. 

One potential method for measuring the size of aerosol nanoparticles is a scanning mobility particle sizer (SMPS), consisting of a differential mobility analyzer (DMA) and a condensation particle counter (CPC). Aerosol particles enter the DMA where they are charged using a radioactive source and their size is classified based on the electrical mobility, Z, of the particles in the applied electrical field ... 

SMPS (scanning mobility particle sizer)—combines a DMA (differential mobility analyzer) and a CPC (condensation particle counter) to measure the... 

In a study of the impact of printers as emission sources of VOCs, ozone and particulate matter on indoor air quality, ultrahne particles have been measured using Scanning Mobihty Particle Spectrometer-Condensation Particle Counter (SMPS-CPC) (Kagia et al. 2007). SMPS distributes from 20 to 500 nm diameter particles and CPC counts ultrahne particles. 

Number concentrations can be determined by sensing zone techniques (see Section 2.4.2), which provide an overall average number concentration. A condensation particle counter (CPC) can provide number concentrations for solid aerosols having particle sizes as small as a few nanometres in diameter [129]. In such an instrument, the aerosol is saturated with a vapour (usually water or an alcohol) and then taken to conditions of supersaturation. Vapour condensation on the particles produces droplets having diameters in the range 5-15 pm [124]... 

Nanoparticle penetration has been measured with a wide range of filter media by using silver nanoparticles from 3 nm to 20 nm at three different face velocities in order to define nanoparticle filtration characteristics of commercial fibrous filter media. After size classification by using a nano-DMA, the particle counts were measured by an ultrafine condensation particle counter (UCPC) both upstream and downstream of the test filter in order to determine the nanoparticle penetration for each specific... 

The calculation of average, volume-equivalent, diameters was based upon total suspended particulate mass and the total number of particles, the latter determined by a condensation particle counter. Aerodynamic size distributions were determined via sedimentation. The operational assumption in this technique is that an insignificant... 

The condensation nucleus counter (CNC), also known as a condensation particle counter (CPC) or ultrafine condensation particle counter (UCPC) are instruments that operate on the principle of flowing aerosol particles through... 

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