Page 26 - Eden Meadow 35 houses application as of 12 October

LAND TO THE REAR OF EDEN MEADOWS, NEWINGTON

AIR QUALITY ASSESSMENT

Model Output

NOx/NO2 Relationship

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4.19 The most recent NOx from NO2 calculator has been used to determine NO2 concentrations
for this assessment, based on NOx concentrations predicted using ADMS-Roads. Converted
NO2 concentrations are initially compared against local monitoring data to verify the model

output. If the model performance falls below acceptable limits then the NOx concentrations
are adjusted before conversion to NO2.

Predicted Short Term Concentrations

4.20 As discussed in the introduction, it has not been possible to model the short-term impacts of
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NO2 and PM10. Research has indicated that the hourly NO2 objective is unlikely to be
exceeded at a roadside location where the annual mean NO2 concentration is less than 60
μg/m . A concentration of 60 µg/m has therefore been used to screen the likelihood of
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exceedance of the hourly mean NO2 objective.

4.21 For PM10, a relationship between the annual mean and the number of 24-hour mean
exceedances has been devised and is as follows:

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• No. 24-hour mean exceedances = -18.5 + 0.00145 x annual mean + (206/annual
mean)

4.22 This relationship has been applied to the modelled annual mean concentrations to estimate
the number of 24-hourly exceedances.

Model Verification

4.23 Monitored NO2 concentrations from the sites listed in Table 5 have been used for the purposes
of model verification. There are no PM10 monitoring stations adjacent to the modelled

network. As such, it has not been possible to verify predicted PM10 concentrations.

11 https://laqm.defra.gov.uk/documents/NOx_to_NO2_Calculator_v7.1.xls
12 Analysis of Relationship between 1-Hour and Annual Mean Nitrogen Dioxide at UK Roadside and Kerbside Monitoring
Sites, Laxen and Marner, 2003
Lustre Consulting Ltd
Report Ref.: 3143/MD/07/2020 Page No. 23