Under Part IV of the Environment Act 1995, local authorities are required to review and assess air quality in their areas. The primary objective of this process is to identify areas where air quality is unlikely to meet the objectives prescribed in the Air Quality Regulations 1997, within the relevant period (by the end of 2005).
The pollutants for which national objectives have been prescribed for under the 1997 Regulations are shown below:
|Pollutant||Standard Concentration||Standard Measured as||Objective to be achieved by the end of 2005|
||running annual mean
||running annual mean
||running 8-hour mean
||150ppb hourly mean
||21ppb annual mean
Running 24hr means
as the 99percentile
|Sulphur dioxide 100ppb
||15 minute mean
||100ppb measured as
The 99.9th %oil
What does monitoring involve?
Air quality monitoring involves measuring the ambient concentrations of pollutants in air at a given place and point in time. The measurements produced are always average values over a defined period of time, which may range from a month to a few seconds. A variety of techniques, of varying sophistication, exist for measuring concentrations of pollutants in air. In order to ensure a cost-effective monitoring strategy, appropriate techniques should be utilised.
The methods fall into four main groups:
- Passive sampling (for example, diffusion tubes)
- Active sampling (bubblers, filters etc)
- Automatic point monitoring
- Long-path/remote monitoring
The Government recommended a phased approach to making reviews and assessments of local air quality where people are regularly present and might be exposed to air pollution.
Local authorities were required to undertake an initial screening process reviewing sources of pollution in the area followed, if necessary, by a more detailed survey using simple monitoring techniques. If these surveys indicated that the prescribed objectives are likely to be exceeded by the end of 2005, then a detailed assessment using accurate monitoring, modelling and other techniques should be undertaken.
East Ayrshire's monitoring activities
Prior to recent legislation, East Ayrshire Council have been monitoring the ambient air quality over a number of years using diffusion tubes to sample NO2 concentrations and 8-port bubblers to sample SO2 and smoke (particulate) concentrations at a various of locations throughout the district.
East Ayrshire Council’s Environmental Health Service has embarked on addressing their obligation under the relevant section(s) on the Environment Act 1995 by:
- Producing an Air Quality Review Study
- Initiating a preliminary diffusion tube survey for the prescribed pollutants
Whilst the Air Quality Review has been submitted to The Scottish Office, the diffusion tube survey is still on going.
The tubes are affixed to pre-identified lamp posts in strategic areas, throughout the district, which have been considered to meet the requirements of the DETR guidelines. These tubes are in their locations for one month per every three months and are analysed by Clyde Analytical Laboratories at Greenock.
Mobile Quality Monitoring Station
East Ayrshire Council has recently taken delivery of a mobile Air Quality Monitoring Station from Enviro Technology Services plc. This unit monitors for:
- Sulphur dioxide (SO2)
- Nitrogen (NO)
- Nitrogen dioxide (NO2)
- Oxides of Nitrogen (NOX)
- Carbon monoxide (CO)
- Particulate (PM10)
All monitoring is logged by real time, electronic analysers and downloaded automatically to an office based PC on a daily basis. The equipment can be programmed for various modes (for example, 15 min. averages) from the PC and analysed accordingly, either statistically and/or graphically, daily, weekly or monthly.
It is anticipated that this station will play a major role in assisting East Ayrshire Council with the monitoring of the prescribed pollutants identified above.