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   Stationary passive samplers  


PS1
Stationary Passive Sampler

The use of small stationary passive samplers for aerosol particles to determine particulate matter (PM10-2.5) concentration in outdoor air is investigated. The passive sampler collects particles by gravity, diffusion and convective diffusion onto a glass substrate that is then examined with an optical microscope. The sensor employed was developed by University of North Carolina and RJLee Group, and it was calibrated vs a laser particle counter (ISO 21501) for periods up to a 15 days.

To investigate particulate matter concentrations in the greater Thessaloniki area a Work Group was initiated by the Technical Chamber of Greece (Northern Greece) in cooperation with the Municipality of Thessaloniki, with the following participants:
- Marc Assael and Kostas Kakosimos (Thermophysical Properties Laboratory, Chemical Engineering Dept. AUTh)
- Dimitri Mela (Laboratory of Atmospheric Physics, Physics Dept. AUTh)
- Kosta Karatza (Informatics Systems & Applications Group, Mechanical Engineering Dept. AUTh)
- Harisios Achillas (Laboratory of Heat Transfer & Environmental Engineering, Mechanical Engineering Dept. AUTh)
Accordind to this project, 20 such sensors wer placed in predetermined places in the city to investigate levels of concentrations of particulate matter. The results of these measurements can be found in www.airquality.gr.

   Personal passive samplers  


PS2
Personal Passive Sampler

The use of small personal passive samplers for aerosol particles to determine particulate matter (PM10-2.5) concentration in outdoor air is employed. The passive sampler collects particles by gravity, diffusion and convective diffusion onto a glass substrate that is then examined with an optical microscope. The sampler employed is developed by Tokai University and Sibata Scientific Technology Ltd to be worn by persons walking. The samplers were callibrated using a laser particle counter (ISO 21501) for periods up to a 15 days.

The passive samplers are going to be worn by 10 persons going about in their everyday activities in the center of the town.

   OSPM  



PM10 hourly concentrations for February 2005

The OSPM model is employed for the calculation of the PM10 concentration levels in the historical centre of the city of Thessaloniki (Greece). Although measurements of the background concentration are available at a suburban station, and a few measurements of PM10 concentrations do exist at particular areas inside the historical city centre, further assumptions had to be made (e.g. for the traffic load) in order to implement OSPM. To validate this approach, NOx and NO2 measurements are employed in addition to data for PM10. The good agreement observed allows the prediction of PM10 concentrations in all streets in the historical city centre. The very high PM10 concentration levels obtained in almost all streets are indicative of the city’s situation today.


Assael M.J., Delaki M., and Kakosimos K., “Applying the OSPM Model in the Calculation of PM10 Concentration Levels in the City of Thessaloniki”, Atmospheric Environment 42:65-77 (2008)

   Mesoscale dispersions  


Air pollution in large cities is mainly attributed to emissions from vehicles and heating. However this may not be 100% true for most of the cases. The majority of modern cities, like Thessaloniki, are located close to industrial areas and bare land. Both these factors contribute in diminishing regional air quality. For this purpose, a local campaign was launched by TPL in order to locate nearby emission sources and collect their characteristics.

Later, all this will be used to simulate in an annual basis the concentration of air pollutants and especially particulate matter. The results will be compared with local measurements from the national monitoring stations and the measuring network of TPL.

 

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