ACTRIS - Aerosols, Clouds, and Trace Gases Research Infrastructure

ACTRIS is the pan-European research infrastructure producing high-quality data and information on short-lived atmospheric constituents and on the processes leading to the variability of these constituents in natural and controlled atmospheres. The ACTRIS network consists of over 100 research facilities hosted by in 17 countries. Collectively, these facilities continuously measure the concentrations of numerous gas-phase species, aerosol, and clouds characteristics, and other properties of the ambient atmosphere. This data also provides insight into the processes that affect atmospheric pollutant levels.

Harmonization: Standard Processes Deliver Higher-Quality Results

ACTRIS measurements are conducted in a ‘harmonized’ fashion. This means that the sampling and measurement techniques are all standardized, hence allowing the intercomparison of data taken at different sites, and/or data taken at the same site at different times of day or year. The data collecting protocols and reporting format are also harmonized.

The specific requirements for making harmonized measurements are provided in formal standards documents. For example, the standards that are relevant to measuring ultrafine particles in the atmosphere are EN 16976* and CEN/TS 17434 (for particle number concentration and particle size distribution, respectively).

Because all ACTRIS measurements and data are harmonized, this enables ACTRIS to organize the data into high-quality final data sets. All of the data are publicly available, to anyone, at no cost. This data is routinely used by governments, researchers, and industry in order to formulate policies, advance science, and develop technologies relevant to improving air quality.

TSI's Contribution to ACTRIS

Air quality measurement efforts rely on using the appropriate tools. Because the ACTRIS network measures a wide variety of atmospheric constituents, a wide variety of instrumentation is needed. ACTRIS measurement strategies include both remote sensing techniques and in-situ measurements. Ultrafine particle measurements, for example, are measured in-situ by pulling a small flow of ambient air out of the environment and through an instrument that can measure the ultrafine particles.

TSI particle counters and particle sizers have been widely used in ACTRIS-affiliated monitoring stations to measure ultrafine particles for years. TSI has a long history of designing Condensation Particle Counters (CPCs), which measure particle number concentration. TSI CPCs are used the world over in a wide variety of applications, including ambient air monitoring.

While CPCs can be used by themselves for number concentration measurements, they are also employed in a component-based system that measures the size distribution of ultrafine particles. This system is known as a Scanning Mobility Particle Sizer, or SMPS™. Both CPCs and SMPSs from TSI have been employed in ACTRIS-participating stations for years. TSI is proud to supply instrumentation and solutions to ACTRIS. More information here: https://www.actris.eu/about

*EN 16976 is formerly known as the Technical Specification CEN/TS 16976, and established by the European Committee for Standardization (CEN).