Is the background concentration and deposition data in the Search by Location tool estimated from measured or modelled data scenarios?

Nitrogen deposition to woodland/forest deposits at a higher rate than to shorter vegetation types. So even at the same location different habitats can receive different depositions of pollutant. This is because forests and woodland habitats have a higher aerodynamic roughness (e.g. leaves, branches etc) as opposed to a shorter type of vegetation habitat types and deposition to woodland habitats can be twice as that for short vegetation.