Manchester Piccadilly Gardens Buses Trams 2

Buses and trams in Manchester Piccadilly Gardens as filmed in 1993 / 4 and 2012.

Some 1990s sequences show diesel buses emitting much visible tailpipe air pollution. Nowadays (2016) bus waste gases are rarely as visible, one reason for this being that the particles are much smaller / finer, which is not necessarily good as smaller particles are more easily breathed in more deeply in to our lungs where they sometimes stay and other times pass in to our blood and are distributed around our bodies.

Another reason for this is that series type diesel hybrid buses have an electric drive system and only use the diesel engine to keep the onboard energy storage batteries topped up. Typically their diesel engines run in a way which is optimised to emit the least possible tailpipe air pollution.

Of course the Metrolink trams are electric, so do not emit any tailpipe pollution at all.