NA3: In-situ chemical, physical and optical properties of aerosols


WP Leader:
Alfred Wiedensohler

Objectives

The overall objective of this activity is to improve the observations of the in-situ aerosol properties (chemical composition, optical, cloud condensation nuclei, size distribution) throughout a network of 23 stations in such a way that the data they provide can be efficiently integrated with those contributed by other parts of the whole ACTRIS infrastructure. NA3 capitalizes on and enhances the work initiated within the EUSAAR I3 program (2006-2011). Following specific objectives are defined:

  • To ensure the implementation of the existing standardized protocols for high-quality-assured and - controlled aerosol number size distributions in the network and to develop procedures for its extension to the nucleation mode range 
  • To ensure the implementation of the existing standardized protocols of high-quality assured and - controlled aerosol measurements of scattering and absorption coefficients and the development of standardized procedures of spectral absorption measurements. 
  • To ensure the implementation of the existing harmonized protocols for sampling and analysis of organic/elemental carbon and to develop standardized protocols for sampling and quantification of organic tracers for source identification
  • To develop standardized protocols for high-quality assured and - controlled measurements of cloud condensation nuclei.
  • To ensure diffusion of information to data centres.

Description of work

 Task 3.1
 Implementation of existing and development of new protocols for particle number size distributions (IFT; UHEL + all)

The EUSAAR standardized protocol for mobility size spectrometers (MSP) will be further implemented in the period of ACTRIS to ensure sustainable measurements of number size distributions and their submission to the data base.
The reference MSP is available for intercomparisons. MSPs can be intercompared on-site on request, but not more than once per station
Nano-mobility size spectrometers (nano-MSP) and ion spectrometer will be standardized and a measurement protocol will be developed. Therefore, an advanced intercomparison workshop will be performed.

   
 Task 3.2  Implementation of existing and development of new measurement protocols for aerosol optical properties (IFT + all)

The EUSAAR standardization of 1-wavelength absorption photometers (1-w-AP) and 3-wavelength integrating nephelometers (3-w-Neph) will be further implemented within ACTRIS to ensure sustainable measurements of aerosol light scattering and absorption coefficients and their submission to the data base.
A standardized protocol to calibrate multi-wavelength absorption photometers (mw-AP) against reference methods will be developed. Reference methods such as photo-acoustic sensors and/or extinction minus scattering methods will be used in an advanced intercomparison workshop.
A 3-w-Neph and a 1-w-AP are available for on-site intercomparison on request, but not more than once per station.

   
 Task 3.3  Implementation of sampling and analysis of organic and elemental carbon and organic tracers for source identification (JRC; ULUND + all)

The EUSAAR standardized sampling and analysis protocol for organic and elemental carbon will be further implemented within ACTRIS to ensure a sustainable data base.
It is planned to get this protocol accepted as European and possibly international reference method, and implemented in national and international (e.g. EMEP) air pollution monitoring networks to ensure that these measurements are consistent throughout Europe. This requires stringent and continuous quality assurance and control activities. Yearly round robin test are planned.
Methods for the quantification of organic tracers will be optimized and standardized in order to quantify sources of particulate organic carbon. The source apportionment of the organic aerosol mass (OA) fraction will be performed on the basis of a) monosaccharide anhydrides as tracers for biomass combustion (levoglucosan, mannosan, galactosan), b) GC-MS molecular tracers (vehicles, petroleum, plant waxes, microbial, higher plants, meat cooking, tire wear etc.), and c) H-NMR spectral fingerprints (biomass etc) and C14 (modern/fossil carbon)
An expert workshop will be performed to establish a base for standardized analyses of the tracers listed above.

 
 Task 3.4  Development of measurement protocols for cloud condensation nuclei measurements (PSI; IFT + all)
 Within ACTRIS, standardized protocols for size- and super-saturation-resolved cloud condensation nuclei (CCN) measurements will be developed to ensure comparable measurements at different stations.
An expert workshop will be performed to define the standardized measurements and data analysis protocol of CCN measurements.

 

 
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