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2009 Further assessment

Local authorities are required from time to time to review and assess air quality within their areas according to the timetable set in the National Air Quality Strategy.

This Further Assessment (FA) report follows on from the comments generated as a result of the consultation process of both the local draft Air Quality Action Plan (AQAP) and the Detailed Assessment (DA) reports, published in 2007. It revisits the following areas:

  • the Nitrogen Dioxide (NO2) detailed modelling for the six Air Quality Management Areas (AQMAs) which were predicted to remain in 2010 (AQMA 3, 6, 7, 9, 11, and 13)
  • the NO2 detailed modelling for Victoria Road North
  • the fine particulate matter (PM10) detailed modelling for AQMA 11 and Victoria Road North
  • the establishment of the ambient air dispersion modelling for 2007 as a base-line year, and 2010 for the target year with the exception of AQMA 11 that is modelled also for 2012

The preparation of this report will allow us to:

  • confirm the extent of exceedance of NO2 annual mean National Air Quality Objective (NAQO)
  • revisit PM10 dispersion modelling already covered by the 2007 DA report

The FA report was prepared in response to the review of road traffic data and the revised modelling approach as prescribed by DEFRA’s latest Local Air Quality Management Technical Guidance, LAQM.TG(09), and has concluded the following:

  • In 2007, exceedences of the annual mean NO2 NAQO were predicted in AQMA’s 6 (London Road, Kingston Road, Fratton Road), 7 (City Centre South) and 11 (Mile End). However, the model did under predict at receptors in AQMA 7 and AQMA 9 (Velder Avenue / Milton Road) where monitoring indicated exceedences in 2007.
  • In 2010, exceedences of the annual mean NO2 NAQO were predicted in AQMA’s 6, and AQMA 11 with and without the City Centre North development.
  • No exceedences of the annual mean PM10 NAQO were predicted in either 2007 or 2010.
  • In 2007, annual mean PM10 concentrations were high enough in AQMA 11 to indicate the potential for exceedence of the PM10 24 hour NAQO.
  • In 2010, an exceedence of annual mean PM10 NAQO was not predicted in AQMA 11, but was with the City Centre North development. This exceedence was also predicted in 2012.
  • Source apportionment predicted that emissions from HGV’s and background concentrations were the predominant sources in most areas.
  • Emissions from cars were more important in AQMA’s 6 and 11 with emissions from buses being more important in AQMA 6 and 13 than in other areas.
  • Shipping emissions made greater contributions in AQMA’s 6, 7 and 11 than in other areas.
  • The required reduction in Nitric Oxides (NOX) emissions to meet the annual mean NO2 objective in 2010 was predicted to be 11.1% for AQMA 11, 24.2% for the City Centre North scenario and 44.7% for AQMA 6.

In light of the above, we can confirm that the FA 2009 report identified the need to consider the following actions:

  • Revocation of eight AQMAs (AQMA 1-5, 8, 10 and 13) based on 2008 monitoring data.
  • Retention of five AQMAs:
    • AQMA 6 and 11, based on the predicted breach of the annual mean NO2 NAQO.
    • AQMA 7 and 9, based on the monitored breach of the annual mean NO2 NAQO.
    • AQMA 12 lack of enough historical monitoring data to justify the revocation at this stage.
  • A review of the geographical extent of AQMA 11 based on 40 µg/m3 contour line of the 2007 base-line dispersion modelling output.
  • Based on monitoring data, the 24-hour mean PM10 was in excess of 50 µg/m3 at all monitored stations in 2007 and 2008. However, the number of exceedances was not in excess of 35 exceedances, and the 2008 annual mean monitored PM10 at all stations was not in excess of 32 µg/m3. Therefore, it is unlikely that there will be future exceedence of the 24-hour mean PM10 NAQO.
    However, in light of the above and low PM10 data capture at C7 (under 90%), it is difficult to state categorically that future exceedences of the 24-hour mean NAQO will not take place. Therefore, monitoring at both stations will continue, and PM10 pollutant will be addressed again in next Review and Assessment (RA) Progress Report 2010.
  • The AQAP should be revisited and updated according to the FA findings to focus on AQMAs that are to be retained (AQMA 6, 7, 9, and 11).

For more information please conatct Redouan Sadak at redouan.sadak@portsmouthcc.gov.uk.

Associated documents:

Media attachment image  2009 Further assessment  (349.59 KB)
Media attachment image  2009 Further assessment (Appendices)  (4379.05 KB)