Passive Diffusion Tubes
Air quality in the Vale is generally good. However, there is one pollutant of potential concern. This is Nitrogen Dioxide (NO2). Monitoring of NO2 is undertaken by:-
Passive Diffusion Tube
This is a simple and relatively inexpensive device consisting of a plastic tube which can be attached to street furniture (e.g. a street light) allowing a sample of air to be collected (over a recorded exposure period) by diffusion into the sampler. The tubes are sealed and then sent off for quantitative analysis. They give a good indication of long term spatial and temporal trends
in pollutant levels.
NO2 is currently measured using this method at 23 sites across the district including: Aylesbury, Waddesdon, Eddlesborough, Winslow, Buckingham and Bierton. Annual average concentrations generated are compared to the long-term National Air Quality Objective for NO2 (40 µg/m3 ). A summary of results obtained from 2006 to 2009 is available to download below.
Automatic Real-Time Monitor
This produces high-resolution measurements over a short averaging period e.g. 15 minutes. The air sample is analysed in real-time. This method offers continuous data, which identifies peaks and troughs during a short period e.g. 24 hours, as well as long term averages. This method is also accurate and reliable enough to inform the decision making process in terms of identifying problem areas.
We currently have two real-time monitors within the district. These are relocated every 6 to 12 months, depending on diffusion tube monitoring results. The monitors are currently located at Friarage Road, Aylesbury and High Street Winslow.
Data generated by these monitors is available to view within the downloadable reports on the Air Quality Review and Assessment pages. Concentrations measured over a 24hr period are compared to the short-term National Air Quality Objective for NO2 (200 µg/m3). Annual average concentrations are compared to the long-term National Air Quality Objective (40 µg/m3 ).
Date Updated: 09/07/10
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NO2 Diffusion Tube Monitoring Results 2006 - 2011
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