National Physical Laboratory

Multi-parameter Measurements of Aerosol Properties for Climate Models

Aerosol chamber

The radiative properties of aerosols are one of the biggest uncertainties in climate change models (IPCC Fourth Assessment Report - Topic 2 Causes of Change, 2007), and aerosols are also a crucial element in air quality. Optical measurements of aerosols are key as they provide a direct measurement of the radiative properties, and can provide remote measurements of spatial distribution and evolution.

NPL, as part of the NMS programme, has developed a new facility within which well-controlled dispersions of nano- and micro-particles can be mixed, conditioned and sampled. This facility (described below) is now available for academic groups and instrumentation companies to calibrate and characterise their instruments and work with NPL to disseminate measurement best practice.

A variety of particle generating and detecting instrumentation has been integrated into the facility allowing instruments to be tested against a wide range of mixtures. The facility also offers measurement windows at 0, 45, 90 degrees, so it is possible to measure forward and side scattering. The flow inside the measurement chamber is laminar.

If you would like to find out more, please email analytical@npl.co.uk

 

Caburn QUK08341 bench drawing


(click to enlarge)
Chamber flow diagram


(click to enlarge)

 

Sources

Type Size Range (nm) Max Concentration (cm-3) Geometric STD Particles
Atomiser 40 to 1,000 1.E+07 1.8 Solutes, e.g. NaCl, sucrose, nitrates, sulphates, oil
Electrospray 20 to 1,000 1.4 As for Atomiser
Suspension
plus DMA to improve selection
50 to 1,000 1.E+07
1.E+04
1.1 PSL reference spheres,
gold, proteins
CAST - Combustion Aerosol Standard 26,55,85,117,156 or
[ 26+156 ]
1.E+06
(1.E+07 in 2010)
  Black carbon
FBAG - Fluidised Bed Aerosol Generator 10 to 10,000+ 1.E+06 1.6 Dry powders, e.g. silicon,
alumina, metal oxides
Spark Generator 2 (primary)
20-100 (agglomerate)
1.E+07 1.6 Black carbon
VOAG - Vibrating Orifice Aerosol Generator 40 to 1,000 1.E+03 <1.1 As for Atomiser,
but mono-dispersed

 

Measurement Instrumentation

Type Size Range (nm) Max Concentration (cm-3) Response Time
CPC - Condensation Particle Counter
(UKAS Accreditation)
10 to 1,000
10 to 100
1.E+07
1.E+05
1 sec
SMPS - Scanning Mobility Particle Sizer 1 to 1,000 1.E+07 3 mins
FPS - Fast Particulate Spectrometer 10 to 2,500 1.E+04 0.1 sec
       
TEOM - Tapered Element Oscillation Microbalance Mass measurement >10 ug/m3 5 mins
Filters and Precipitation Mass and composition n/a n/a
       
OPC - Optical Particle Counter
(from 2010)
500 to 10,000+ 1.E+04 tbd



Last Updated: 18 Aug 2015
Created: 9 Aug 2010

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