Acid Neutralisation Capacity (ANC)

Ability of a solution to neutralise inputs of strong acid to a preselected equivalence.  An important chemical parameter used in critical load calculations.

Acidification

The shift of an ecosystem in its physical characteristic towards higher acidity. Acidification is caused by anthropogenic input of acidifying compounds, manly sulphur and nitrogen compounds, into an ecosystem in excess of its ability to buffer the acidifying effects.

Base Cations

Sum of calcium, magnesium, sodium and potassium cations.

CCC

Chemical Coordinating Centre

CCE

Coordination Center for Effects

CIAM

Centre for Integrated Assessment Modelling

CLRTAP

Convention on Long-range Transboundary Air Pollution

Critical Levels

Concentrations of pollutants in the atmosphere above which direct adverse effects on receptors, such as human beings, plants, ecosystem or materials may occur, according to present knowledge.

Critical Load

A quantitative estimate of an exposure to one or more pollutants below which significant harmful effects on specified sensitive elements of the environment do not occur, according to present knowledge.

EMEP

European Monitoring and Evaluation Programme

EMEP-SB

Cooperative Programme for Monitoring and Evaluation of Long-range Transmission of Air Pollutants in Europe – Steering Body

Emission

The release of a substance from a point or diffuse source into the atmosphere.

Eutrophication

Anthropogenically caused build-up of nutrients that causes natural nutrient inbalance in an ecosystem and may alter its structure.

Ground-Level Ozone

Secondary ozone pollution, formed through photochemical processes in the atmosphere at the presence of nitrogen oxides, volatile organic compounds and sunlight.

ICP

International Cooperative Programme

MRC

Main Research Centre

MSC-E

Meteorological Synthesizing Centre – East

MSC-W

Meteorological Synthesizing Centre – West

Nitrogen oxides

Are nitrogen oxide and nitrogen dioxide, expressed as  NOx

PC

Programme Centre

PCC

Programme Coordination Centre

Receptors

An ecosystem, or part of an ecosystem of interest that is potentially impacted by pollutant concentrations or atmospheric deposition.  Receptors under the Convention are also materials.

Reduced nitrogen compounds

Means ammonia and its reaction products.

SSMB (SMB)

Steady-State Mass Balance model (Simple Mass Balance model

TF

Task Force

TFEIP

Task Force on Emission Inventories and Projections

TFIAM

Task Force on Integrated Assessment Modelling

TFMM

Task Force on Measurement and Modelling

UNECE

United Nations Economic Commission for Europe

Volatile organic compounds (VOCs)

Are all organic compounds of an anthropogenic nature, other than methane, that are capable of producing photochemical oxidants by reaction with nitrogen oxides in the presence of sunlight.

WGE

Working Group on Effects

WGSR

Working Group on Strategies and Review