Gianna, that is the hillside upon which I live. The yellow-brown
pollution haze which you mention is only occasionally visible ...
on days of light or no wind with high RH and otherwise good
visibility ... and comprises diesel fumes along the line of the M1
which parallels the western horizon as viewed from up here.
Otherwise Luton is no more polluted than any other town in
Southeast England now that all the manufacturing industry has
gone, much as some might like to think otherwise :-p

Philip Eden
The pollution I used to experience in St Albans when the wind was in the
north was the sulphurous smell from the Bedfordshire brick works and I
presume this was also noticeable in Luton. In recent years this does not
seem to have occurred which is either due to the works closure or emission
control - probably the former given the collapse of manufacturing industry.

Alan