The following charts illustrate changes in the annual average concentration of three air pollutants which have occured since 2012.  The measurements reflect conditions in the immediate vicinity of the monitoring site rather than in the named locality.  The measurements for 2022 have yet to be fully ratified.  They are based on London Air.

 

The following four charts illustrate trends in nitrogen dioxide concentrations as measured since 2014 using diffusion tubes across Greenwich.  Concentrations at several of the locations exceed the current legal limit.  The data, based on Royal Borough of Greenwich, have not been adjustment for bias.  Estimates have been made for March to June 2020 inclusive (when covid-19 restrictions were in place) and other months if data is missing or spurious.  The uppermost chart refers to sites where triplicate measurements were made.