LAQS

The indoor smog chamber facility located at the Institute of Chemical Engineering has been carefully designed and constructed to provide the means for studying important atmospheric processes such as particle formation, photochemical aging and secondary organic aerosol formation.

The indoor smog chamber facility is a 30 m³ temperature controlled room that can host custom-made Teflon smog chambers of variable sizes (up to 12 m³). The chamber room has aluminum coated walls and is equipped with a series of black light lamps that emit in the wavelength range between 300 and 450 nm and have the ability to simulate sunlight conditions that range from a very sunny day (J_NO2 = 0.6 min^-1) to a partially cloudy day (J_NO2 = 0.2 min^-1). A suite of state-of-the-art instrumentation is used to follow both the gas (PTR-MS, O₃ and NO_x monitors etc.) and aerosol phase (HR-ToF-AMS, SMPS, CCNc etc.) processes inside the smog chamber.

The main laboratory of LAQS is located at the Institute of Chemical Engineering (ICE/FORTH) around 1 km away from the University of Patras. The main scientific objectives of the laboratory are to study the physical and chemical properties of atmospheric particles and gases, related to atmospheric pollution. The laboratory is equipped with a variety of instrumentation appropriate for the measurement of chemical composition, the mass concentration, size, volatility, water solubility, hygroscopicity of atmospheric particles and the monitoring of certain gases. A series of controlled (in a smog chamber) and uncontrolled (ambient) experiments and measurements are conducted in order to investigate the corresponding atmospheric processes. Current studies are focusing on:

• The investigation of emissions from wood burning and their atmospheric processing
• The properties of biogenic and anthropogenic pollutants and their oxidation products
• Oxidation mechanisms of gaseous species and secondary organic aerosol formation and aging
• Evaluation of photochemical mechanisms
• Exploration of chemical composition, gas/particle partitioning, hygroscopicity and volatility of SOA
• Formation and growth of nanoparticles

Volatility Measurements with Thermodenuder

The Thermodenuder is an instrument used for the measurement of the volatility of atmospheric aerosol coupled with a High-Resolution Aerosol Mass Spectrometer (HR AMS) and/or a Scanning Mobility Mass Spectrometer (SMPS). Details about the design and the performance of our Thermodenuder can be found in An et al. (2007).

(An W. J., R. K. Pathak, B. H. Lee, and S. N. Pandis (2007): Aerosol volatility measurement using an improved thermodenuder: Application to secondary organic aerosol, J. Aeros. Sci., 38, 305-314)

Temperature-controlled laminar flow reactor

The reactor is a 4 m long tube consisting of 2 concentric cylinders. Water with the desired temperature circulates in the cylindrical annulus. The aerosol used in the experiment flows along the inner cylinder. There are five sampling ports along the reactor. The reactor is used for aerosol growth and evaporation experiments.

This laboratory is located in the Chemical Engineering Department of the University of Patras. It is used for analysis of filter samples collected throughout the various sampling sites. GC-MS analysis for the characterization of the organic compounds of the aerosols and Thermal Optical Analysis for the characterization of the Organic (OC) and Elemental Carbon (EC) are performed there.

The Finokalia station is located at a remote coastal site in the northeast of Crete (35° 20’N, 25° 40’E and 250m above sea level). The site is isolated and far away from anthropogenic emissions, and therefore allows the study of aerosols originated from Europe, Balkans, Africa, as well as marine aerosol. Due to the high photochemical conditions the Finokalia station is an ideal location to study the aging of the organic aerosol as well. The LAQS group has participated in three field campaigns at the Finokalia site: FAME-08, FAME-09 and FAME-11. The station is run by the Environmental Chemical Processes Laboratory of the University of Crete (ECPL) and it is part of the EUSAAR and ACTRIS Network and reports to the EMEP database.

The urban measurement station of the team is at the roof of a building (at around 30 m above ground level) in the center of Patras, a city with 300,000 inhabitants. The building is one of the tallest in the city and the station provides measurements of the urban background. A PM_2.5 sampler is located there and is used for routine measurements of the aerosol mass concentration and composition. Additional instruments (gas and aerosol) are added during intensive measurement periods. The station has been operating since 2009.

Our rural sampling station is located on a water tower in the small village of Vouprassio (38° 04’N, 21° 23’E) 36 Km west of the city of Patras. The site is often upwind of the city. Measurements are performed there to quantify the contribution of transported pollution to the air quality in the city of Patras. The instrumentation in the site is a filter sampler (Met – One Super-SASS) that allows us to collect multiple PM_2.5 samples and meteorological station. Additional measurements are performed during intensive campaigns taking advantage of the room that exists in the basis of the tower.

LAQS has developed and commissioned a Mobile Laboratory (Mercedes-Benz Sprinter light duty van) for air quality monitoring and field experiments using mobile smog chambers. The laboratory has a flexible design allowing the use of different instrumentation depending on the measurement objectives.

The LAQS Mobile Lab is equipped with a number of monitors for gas-phase (CO, NO, NO₂, O₃, SO₂, Volatile Organic Compounds using a PTR-MS) and particle-phase (size distribution, mass/composition distribution using an Aerosol Mass Spectrometer, black carbon) pollutants and their properties (scattering, absorption, volatility).

It can be used as fixed monitoring station, a mobile measurement platform or as an actual mobile laboratory allowing performance of smog chamber experiments in the field using ambient air.