Network activity 6:

Audits and capacity building

Objectives and expected impact

A major objective of EUSAAR is that activities consolidate current observation efforts and ensure their continuation beyond the present project. This will be done implementing regular audits at monitoring stations and by promoting capacity building with specialized training courses and workshops.

The production of high quality aerosol data not only requires the harmonization and quality control of aerosol instrumentation but also a very careful implementation of the global sampling and analyzer system. An essential element in the study of aerosols is the ability to collect representative samples for analysis. These samples must accurately reflect the original aerosol population in both concentration and size. The problems related with aerosol sampling and the possible malfunction of the entire data production chain will be addressed within EUSAAR. This will be implemented with the following tasks:

Objective 1

Standardisation of aerosol inlets for physical and chemical aerosol sampling:
Defined aerosol inlets to sample aerosol particles are essential to provide comparable aerosol data. The agreement within existing networks (EMEP, GAW) is to use PM10 inlets (particles larger 10 µm are removed). The reason is that larger particles can only be collected with high uncertainties and they are probably only locally suspended in air. A standardisation to PM 10 inlets will help to make aerosol data more comparable and useful for data users.

Objective 2

Advice in construction of special inlets for stations in extreme environments:
Some of the stations (mountain sites, sites in the Arctic region) underlie conditions where usual PM10 inlets do not work. Mountain stations are often in clouds, thus special inlets must be designed to also allow for the collection of cloud droplets (droplets are formed from aerosol particles). At other sites, the inlets are clogged by droplet freezing and snow. Here, some development is still needed to heat such inlets without modifying the aerosol chemical, physical and optical properties. Carefully designed inlets for such stations help to improve the quality of the aerosol measurements.

Objective 3

Standardisation of the relative humidity for aerosol sampling:
Usually, the temperature in the station laboratory is controlled by air conditioning systems. In summer, a temperature decrease will lead to an increase in humidity in the aerosol sampling lines and instruments. High relative humidity will lead to aerosol properties which are not comparable with measurements at lower humidities (particles take up water with increasing relative humidity). A standardisation to allow only relative humidities below 50% (with individual advice how to reduce the relative humidity) will significantly increase the comparability of aerosol data sets (this activity will be performed in coordination with N4 and JRA2).

Objective 4

Frequent aerosol training courses for aerosol physics, sampling, in-situ physical, and optical measurements, and OC/EC analysis:
Operational errors are one of the major reasons for less quality aerosol sampling and measurements. It is therefore essential that station personnel must be trained to perform aerosol sampling and measurements but also to understand working principles of the instrumentation. Frequently trained people will help to keep a high quality of aerosol measurements leading to comparable aerosol data sets. Training courses will benefit from the experience of some partners in the Nordic Society for Aerosol Research.

Objective 5

Audits of all station in terms of inlet designs, in-situ physical and optical measurements:
To control the quality of aerosol sampling and measurements, audits of the station are important. Often, small operational errors cause great impacts on the data quality. To avoid such operational errors, and to allow a direct communication with the station personnel, all stations will be audited. The great impact is that there will be a control if all standardisations are well established so that at the end of the project all stations can deliver comparable and trustable aerosol data sets.

Description of work

First, the activity leader will ask all station managers to provide a description of the aerosol inlet configuration, flow rates und flows to be used for the different aerosol measurements and samplings, and of the environmental conditions under which the atmospheric aerosol will be collected. Furthermore, it should be verified that the relative humidity of the aerosol in the station laboratory does not exceed 50% at any time during the seasons. Therefore a questionnaire will be sent to all stations.

Based on the outcome of the questionnaires, the activity leader will suggest necessary improvements for inlets and sampling configurations. For stations in extreme environments (frequently in clouds, clogging due to freezing droplets or snow etc.), the activity leader in cooperation with participant 2 will provide individual solutions

There is still a great need for frequent training courses to improve the skills of station personnel and young scientists working with the data. For this reason, it is planned to perform 3 aerosol training courses during the project duration. The training courses given by the activity leader will focus on aerosol physics, sampling, and instrumentation for physical and optical measurements.

The activity leader hosts the World Calibration Centre for Physical Aerosol properties on the behalf of the WMO in the framework of GAW. Parts of the duties are to help with the implementation of new aerosol measurements as well as the major task of auditing aerosol stations. The plan in this network activity is to audit every station during the project duration. The station manager will obtain a report describing the quality of the measurements including suggestions for improvements.