Glossary of Terms

• 1,3-Butadiene (C4H6)
• Acid Deposition
• Acid Rain
• Air Pollution Bandings
• Air Pollution Bulletins
• Air Pollution Index
• Air Pollution Information Service
• Air Quality Management Area (AQMA)
• Air Quality Objectives
• Air Quality Standards
• Air Quality Strategy
• Ambient Air
• Annual Mean
• Automatic Monitoring
• BAM (Beta Attenuation Mass Monitor)
• Benzene (C6H6)
• Black Smoke
• Carbon Monoxide (CO)
• COMEAP
• Data Capture
• Days with Exceedences
• Diffusion Tube Samplers
• Dispersion model
• EMEP (Co-operative Programme for Monitoring and Evaluation of the Long-Range Transmission ofAir pollutants in Europe)
• Emission Factor
• Emission Inventories
• EPAQS

• EU Directives
• Exceedence
• Global Warming
• Gravimetric Equivalent PM10 Data
• Greenhouse Gases
• Hydrocarbons
• Local Air Quality Action Plan
• Local Air Quality Management (LAQM)
• Maximum hourly average
• Microgrammes per cubic metre (µg/m³)
• National Atmospheric Emissions Inventory (NAEI).
• National Statistics
• Oxides of Nitrogen (NOx)
• Ozone (O3)
• PAHs
• Particulate matter (PM10)
• Percentile
• POPS
• ppb
• ppm
• Running mean

This is a mean - or series of means - calculated for overlapping time periods, and is used in the calculation of several of the national air quality standards.

For instance, an 8 hour running mean is calculated every hour, and averages the values for eight hours. The period of averaging is stepped forward by one hour for each value, so running mean values are given for the periods 00:00 - 07:59, 01:00 - 08:59 etc. By contrast a non-overlapping mean is calculated for consecutive time periods, giving values for the periods 00:00 - 07:59, 08:00 - 15:59 and so on. There are, therefore, 24 possible 8-hour means in a day (calculated from hourly data) and 3 non-overlapping means.

• Sulphur Dioxide (SO2)
• TEOM
• TOMPS
• Trajectory Model
• Volatile organic compounds (VOCs)
• Zones and Agglomerations