5. Projections for roadside sites
5.1 The graphs
Site specific projections for roadside sites are shown in
Figures 23 to 37.
Figure 23 Comparison of measured NOx and NO2 concentrations at London Cromwell Road with projections based on 1995 monitoring data.
Figure 24 Comparison of measured NOx and NO2 concentrations at London Sutton Roadside with projections based on 1997 monitoring data.
Figure 25 Comparison of measured NOx and NO2 concentrations at London Tower Hamlets Roadside with projections based on 1997 monitoring data.
Figure 26 Comparison of measured NOx and NO2 concentrations at London Haringey Roadside with projections based on 1997 monitoring data.
Figure 27 Comparison of measured NOx and NO2 concentrations at London Camden Roadside with projections based on 1997 monitoring data.
Figure 28 Comparison of measured NOx and NO2 concentrations at Exeter Roadside with projections based on 1997 monitoring data.
Figure 29 Comparison of measured NOx and NO2 concentrations at Bristol Old Market with projections based on 1997 monitoring data.
Figure 30 Comparison of measured NOx and NO2 concentrations at Bath Roadside with projections based on 1997 monitoring data
Figure 31 Comparison of measured NOx and NO2 concentrations at Glasgow Roadside with projections based on 1997 monitoring data.
Figure 32 Comparison of measured NOx and NO2 concentrations at Loncoln Roadside with projections based on 1997 monitoring data.
Figure 33 Comparison of measured NOx and NO2 concentrations at Bury Roadside with projections based on 1997 monitoring data.
Figure 34 Comparison of measured NOx and NO2 concentrations at London A3 Roadside with projections based on 1997 monitoring data.
Figure 35 Comparison of measured NOx and NO2 concentrations at Norwich Roadside with projections based on 1998 provisional monitoring data
Figure 36 Comparison of measured NOx and NO2 concentrations at London Marylebone Road with projections based on 1998 provisional monitoring data.
Figure 37 Comparison of measured NOx and NO2 concentrations at Hove Roadside with projections based on 1998 provisional monitoring data.
Projections have been calculated for all sites with at least
one year of measurement data and are based on 1997 monitoring data for most of
the sites. Sites classified as both Kerbside (within 1 m of the kerb) and
Roadside (generally 1 - 5 m from the kerb) have been included. Projections for
Cromwell Road are based on 1995 data, the most recent year with reasonably
complete data capture. The projections for Norwich Roadside, London Marylebone
Road and Hove Roadside are the same as those included in the review of the NAQS,
which were based on provisional measurements covering most of 1998. The roadside
enhancement of NOx concentrations at each site was calculated by
subtracting mapped estimates of background concentrations (from Stedman, 1998)
for the 1 km grid square including the location of the roadside site from the
roadside annual mean measurement. The roadside enhancement of NOx was
then projected forwards and backwards on the basis of the estimates of UK urban
road traffic emissions listed in Table 1. The background component was projected
on the same basis as the site specific projections for urban background sites in
section 4, with 10% of 1996 emissions remaining constant throughout. The graphs
show the following information:
5.2 General conclusions
The backwards projections generally show reasonable agreement with the limited amount of monitoring data that is available. This confirms the conclusions in the review of the NAQS report that many of these roadside sites are likely to be at risk of exceeding the 21 ppb objective in 2005.