The viewed period can be reduced by using the sliders on the year bar at the
bottom. Select All data capture to see progress in the current year.
The solid black line across the graph represents the limit value for the selected objective, and the
dots turn from green to red if the site has failed the selected objective for that year.
Hover over a specific dot to get detailed information for that site on that year.
Hover over line to highlight the whole trend for that site.
The solid black line across the graph represents the limit value for the selected objective, and the
dots turn from green to red if the site has failed the selected objective for that year.
Hover over a specific dot to get detailed information for that site on that year.
Hover over line to highlight the whole trend for that site.
Activating any of the four filters at the top then reduces the list of local authorities, on the
right, to only include those that have at least one site matching the filtered criteria.
A single local authority can be selected by clicking on it, or multiples by holding down the shift
key while selecting with the mouse.
This enables you to choose the geographic area you want from any combination of
- Inner London (criteria) within 10km of Westminster
- Outer London within the boundary of London but outside 10km of Westminster
- Outside London (The LAQN includes sites from areas surrounding London itself)
Not all monitoring sites are in the same type of location. Some are located to directly monitor
emissions from specific roads, others are located away from roads to give a background level that
the wider area and population is exposed to. This filter can be used to select any combination of
types.
The many official classification types have been simplified into 3 groups.
- Background (These represent levels experienced by the general population and provide a
baseline to compare roads to. Includes Background and Suburban classifications. At present
there are no Rural classified sites within the LAQN)
- Roadside (Sites positioned along side busy roads. Includes Kerbside (less than 1m from kerb)
and Roadside (less then 5m from kerb) classifications
- Industrial (sites influenced by industrial activity e.g close to waste transfer sites,
quarry haul routes etc)
On the graphs the dot size also shows the site type for extra clarity; Large - Industrial,
medium-Roadside, small – Background.
This represents the amount of valid data as a percentage of the year. As well as down time for
routine maintenance and calibration many other things can result in data loss; power cuts, flooding,
lightening strike, and faults from general wear as a result of running sensitive equipment 24 hours
a day 365 days a year often in challenging polluted roadside locations.
- 90%+ This is what is aimed for
- 75%+ Even if a site achieves less than 90% it can still be reported above 75% as long as the
loss does not represent a specific time period, e.g if all of 3 months of winter was lost.
- All This should be used with caution since it will also show sites where there is
insufficient data for the results to be reportable. This is included to allow the progress
on the current year to be seen, and to show when sites were operational.
Hovering over any individual dot on the visualisations will give additional information regarding
that site for the year, including the actual data capture rate.