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Iskrba
-SO2-
| Observation |
| Category |
: |
Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
Local time +1 |
| Sampling |
| Sampling height |
: |
4 |
| Description |
: |
filter |
| Sampling and analysis frequency |
: |
Continuous 24-hour sampling with air flow of about 14 liters per minute through three consecutive filters. Filter exchange takes place at 8:00 AM UTC+1 every day. The second filter is KOH impregnated cellulose filter, Whatman 40, which absorbs acid gas SO2. After sampling the filters are extracted in the laboratory and the leaching solution is analysed by ion chromatography. |
| Sampling environment |
: |
Iskrba monitoring site is regional station, part of the Slovenian national monitoring network for monitoring the background air polution. It is located on a plateau at approximately 500 m a.s.l. in a prevalently woody area and within transitional climate zone. The plateau is surrounded by the hills and mountains of approximately 800-1200 m a.s.l.. The surrounding area is mostly forest (prevailingly coniferous trees). The rest is grass land (not grassed by domestic animals) and partly also farmed (grass, pasture). |
| Description for sampling analysis |
: |
Manual sampling method - filter pack, KOH- impregnated cellulose filter, Whatman 40, 17-23 m3/day.
Following the EMEP manual for sampling and chemical analysis sampling is performed on the second cellulose KOH impregnated filter, Whatman 40 which absorbs acid gas SO2.
The air intake has a cylindrical, vertical section 15 cm wide an 25 cm high. This air intake reduces the sampling efficiency for particles larger than 10 um a.e.d.. The filter pack is placed directly in the air intake, and it has separate supports for the aerosol and the impregnated filters in order to avoid contamination from one filter to the next. |
| Instrument and Analysis |
| Measurement method |
: |
Ion Chromatography |
| Current status and history of instrument |
: |
Sampling instrument:
1996 May – present; EK; NILU, Department for instruments and field sampling.
Chemical Analysis:
May 1996-December 2003 – Ion Chromatograph Waters
Januar 2004 – present; Ion Chromatograph Dionex DX120;
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| Description of instrument |
: |
Sampling:
EK sampler with GAST oil-less diaphragm vacuum pump Model DOA and Actaris gas-meter G1,6 DN 15. The accuracy of commercial gas meters is typically within +/- 5%.
Chemical analysis:
Range: 0,10 – 45 mg/L
Linearity: 0,10 – 10 mg/L
Calibration curve: 0,10 – 10 mg/L
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| Calibration |
| Current scale employed in the measurement |
: |
Calibration of the volume meter once per year. |
| Measurement calibration |
: |
Sampling:
Checking of Gas meter is carried out every 5 years in accredited laboratory with air at atmospheric pressure in the measuring line with the etalon.
Chemical analysis:
Calibration by Authorized Service every 2 years
Calibration (7 points) at least one per 2 years
Interlaboratory Comparison EMEP (1x / 1year), GAW (2x / 1year)
Regular use of control sample, prepaired from RM, traceable to SRM, NIST |
| Scale and calibration(treasability) |
: |
Sampling:
Traceable to national and international etalons.
Chemical analysis:
RM, traceable to SRM, NIST used for Controll samples. |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
Daily data is calculated from quantity of SO2 determined in 24h extract from KOH impregnated filters, devided with quantity of air (293°K) pumped through filter in sampling period, to get concentration of SO2 in µg/m3. To get ppm units, the data in µg/m3 SO2 is devided with factor 2,66.
All 24-hour data is controlled (EMEP EDC program) and flagged. Valid and invalid data is reported. Flags indicates the validity of data.
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| Processing for averaging |
: |
Processing for Monthly Data:
Monthly SO2 data are generated by arithmetic means from the valid daily data. |
| Data flag |
: |
The list of EMEP data flags is used. List of flags is available on EMEP homepage / CCC / Data submission / List of flags used in EMEP data base (http://www.nilu.no/projects/ccc/submission.html).
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| Data remarks |
: |
exchange of filters at 07:00 UTC (= 08:00 UTC+1) |
| Other Information |
| Scientific aim |
: |
To provide data for research and study to reveal long term trends. |
| Reference |
: |
EMEP co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe, 1996;
EMEP manual for sampling and chemical analysis (EMEP/CCC-Report 1/95, Reference: O-7726, Norwegian Institute for Air Research, Date: March 1996, Revision: November 2001) (http://www.nilu.no/projects/ccc/manual/index.html). |
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| submitted by Slovenian Environment Agency |
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