GRAPHS
Emission-Watch takes readings of the burden of particulates in the air every 15 seconds. These are then averaged to every 15 minutes for ease of data handling. We have plotted these readings in to graph form and will present them on a weekly basis. All readings are taken from midnight to midnight, Greenwich Mean Time. On some occasions there will be gaps in our data. This is due to circumstances beyond our control, for example routine maintenance or power failure. We apologise if this happens to coincide with a period in which you have particular interest. Emission-Watch will not reveal the exact location of our air monitors for reasons of security.

The graphs are simplified for ease of reading. The red line represents the total concentration (in units of µg/m^3) of particulates in the air and the dark blue line the concentration of particulates up to PM10 . The horizontal light blue line indicates the regulatory limit.

These graphs will show when the regulatory limit is exceeded for each 15 minute period.

However, visitors to the site should be aware that the National Air Quality Strategy requires that the 24 hour mean should not exceed a limit of 50µ/m3 on more than 35 occasions during one year. The annual mean concentration allowed is limited to 40µ/m3.

Please contact the Environment Agency if you would like to know more about the National Air Quality Strategy.

Emission-Watch keeps an extensive data base of all its readings, including the particulate burden up to PM2.5 and PM1. This data is not included on the web site because of the massive size of the files.

If visitors would like to have more in depth details of particular periods that interest them please contact us with your request.

Click here to view details of our filter analysis.

Please note that as of March 2007 older graphs are now being archived in our graphs archive section. The graphs available on this page are now limited to the last few months of data collection.

Please click on the graphs to download: