The Cooperative programme for monitoring and evaluation of long-range transmission of air pollutants in Europe (EMEP) was launched in 1977 as a response to the growing concern over the effects on the environment caused by acid deposition. EMEP was organized under the auspices of the United Nations Economic Commission for Europe (ECE). Today EMEP is an integral component of the cooperation under the Convention on Long-range Transboundary Air Pollution.
The main objective of EMEP is to provide governments with information on deposition and concentration of air pollutants, as well as on the quantity and significance of long-range transmission of pollutants and transboundary fluxes. The programme includes three main elements: emission data, measurements of air and precipitation quality, and atmospheric dispersion models. The work is co-ordinated by three international centres: two centres for modelling activities and one Chemical Co-ordinating Centre (CCC) for coordination of the chemical measurements.
This manual describes the standard recommended methods for sampling and chemical analysis for the EMEP measurement network. The methods and procedures are generally derived from the development and experience gained within EMEP as well as information provided by similar programmes in North America, World Meteorological Organization, various research programmes and numerous EMEP workshops.
The measurements within EMEP are carried out by national laboratories, reporting the results to a common data base at the CCC. Experience has shown that measurements should be standardized as much as possible to obtain data which are comparable and of sufficient quality to allow meaningful comparisons with model calculations, calculation of trends and other statistical evaluations. In addition, quality assurance has to be carried out on both the national level and by the CCC to ensure satisfactory data quality. This applies both to individual samples and particularly to long-term aggregated values, such as seasonal or yearly mean values and trends. It is particularly important to avoid errors which may result in systematically too low or too high results, and undefined changes in the data quality over time, which may cause problems in trend analyses.
For the majority of the methods, the necessary quality assurance is facilitated by a combination of simple and robust sampling techniques with well-described sampling equipment, and use of synthetic control samples for the chemical analyses.
The representativity of a site is a highly relevant question for a measurement network such as EMEP. This can only be determined in relation to the purpose of the measurements. For EMEP the site must be positioned in such a way that the air quality and the precipitation is representative of a larger region. In order for the site to be representative, influences and contamination from local sources must be avoided.
During the period of EMEP operations, considerable improvements have taken place with respect to the development of instrumentation for chemical analysis.
EMEPs measurement programme and recommended methods described in the manual
Components |
Measurement |
Measurement frequency |
Sampling methods |
Methods in laboratory |
Gas |
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SO2 |
24 hours |
daily |
KOH impregnated filters |
IC / (Thorin) |
NO2 |
24 hours |
daily |
NaI impregnated glass frit |
IC / Griess |
O3 |
hourly means stored |
continuously |
UV absorption |
|
HNO3 |
24 hours |
daily |
denuder |
IC / Griess after reduction |
NH3 |
24 hours |
daily |
denuder |
IC / Indophenol |
Light hydrocarbons C2-C7 |
10-15 mins |
twice weekly |
steel canisters |
GC |
Ketones and aldehydes (VOC) |
8 hours |
twice weekly |
DNPH cartridge |
HPLC |
Hg |
24 hours |
weekly |
Gold traps |
CV-AFS |
Particles |
||||
SO42- |
24 hours |
Daily |
aerosol filter |
IC / (Thorin) |
NO3- |
24 hours |
Daily |
aerosol filter after denuder |
IC / Griess after reduction |
NH4+ |
24 hours |
Daily |
aerosol filter after denuder |
IC / Indophenol |
Na+, Mg2+, Ca2+, K+, Cl- |
24 hours |
Daily |
aerosol filter |
IC / AAS / AES |
PM10 |
24 hours |
Daily |
EN 12341 |
micro balance |
PMx |
24 hours |
Daily |
To be decided |
micro balance |
Mineral dust |
24 hours |
Daily |
EN 12341 |
INAA, PIXE, XRF |
EC and OC |
24 hours |
Daily |
EN 12341 |
Thermo desorption and oxidation |
OC-speciation |
24 hours |
once a week |
EN 12341 |
LC-MS |
Cd, Pb (first priority), |
weekly |
weekly |
EN 12341 |
ICP-MS / GF-AAS |
Gas + particles |
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HNO3(g)+NO3-(p), |
24 hours |
daily |
Filter pack |
IC / Griess after reduction |
NH3(g)+NH4-(p) |
25 hours |
daily |
Filter pack |
IC / Indophenol |
POPs (PAH, PCB, HCB, chlordane, lindane, a-HCH, DDT/DDE) |
to be decided |
to be decided |
PUF (polyurethane foam) sampler |
GC-MS |
Precipitation |
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Amount |
24 hours (weekly) |
daily (weekly) |
rain gauge |
By weight |
SO42- |
24 hours (weekly) |
daily (weekly) |
wet only |
IC |
H+ |
24 hours (weekly) |
daily (weekly) |
wet only |
titration |
pH |
24 hours (weekly) |
daily (weekly) |
wet only |
pH meter |
NH4+ |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / Indophenol |
NO3- |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / Griess after reduction |
Na+ |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / AES |
Mg2+ |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / AAS |
Cl- |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / Thiocyanate |
Ca2+ |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / AAS |
K+ |
24 hours (weekly) |
daily (weekly) |
wet only |
IC / AES |
24 hours (weekly) |
daily (weekly) |
wet only |
Cond-meter |
|
Cd, Pb (first priority) |
weekly |
weekly |
wet-only |
ICP-MS / GF-AAS |
Hg2+ |
weekly |
weekly |
wet only |
CV-AFS |
POPs (PAH, PCB, HCB, chlordane, lindane, a-HCH, DDT/DDE) |
to be decided |
to be decided |
wet-only |