1. Introduction

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.

 

EMEP’s measurement programme and recommended methods described in the manual

Components

Measurement
period

Measurement frequency

Sampling methods
in field

Methods in laboratory

Gas

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),
Cu, Zn, As, Cr, Ni (second priority)

weekly

weekly

EN 12341

ICP-MS / GF-AAS

Gas + particles

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

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)
Cu, Zn, As, Cr, Ni (second priority)

weekly
weekly

weekly
weekly

wet-only

ICP-MS / GF-AAS

Hg2+

weekly 
(1 sampler) (or monthly 
(2 samplers))

weekly
(or monthly)

wet only
IVL sampler

CV-AFS

POPs (PAH, PCB, HCB, chlordane, lindane, a-HCH, DDT/DDE)

to be decided

to be decided

wet-only

 


Last revision: November 2001