Temporal and spatial patterns of nitrogen dioxide concentration in the conurbation of Greater Manchester

This paper will examine the spatial and temporal distribution of ambient nitrogen dioxide concentrations in the conurbation of Greater Manchester where monitoring has been undertaken since 1986 in a network of over 70 sites covering an area of some 1300 km2. This represents one of the few long term, continuously operated networks in the UK. A passive diffusion tube is deployed at each site with a sampling frequency of one week. Operation of the network is in conjunction with local government in the region. Sites are stratified into 5 classes; commercial, industrial, residential, arterial road and rural. Sites are differences between sites and classes are discussed. Data from the beginning of the survey in 1986 are presented. Seasonal variability is evident although the long term indicates no substantial increase or decrease in concentration. The areas of high concentration are those of high daily traffic flows, in particular the city centre of Manchester.