2013 Air Quality Progress Report
for North Norfolk District Council
In fulfillment of Part IV of the Environment Act 1995
Local Air Quality Management
May 2013
North Norfolk District Council
Local Authority
Officer
North Norfolk District Council
Contaminated Land Officer
Department
Telephone
e-mail
Environmental Health
North Norfolk District Council
Holt Road
Cromer
Norfolk
NR27 9EN
01263 516085
ep@north-norfolk.gov.uk
Report Reference
number
Date
May 2013
Address
LAQM Progress Report 2013
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North Norfolk District Council
Executive Summary
Annual monitoring within the North Norfolk District since 2003 has continually
demonstrated an adherence to the National Air Quality Objectives. In accordance
with proposals stated within the 2009 Updating and Screening Assessment (NNDC,
2009) further assessment of the Hoveton area using a continuous NOx analyser was
undertaken during a 12 month period between 2011 and 2012. Concentrations of
NOx in this area were historically close to the National Air Quality Objective and
continuous monitoring was undertaken to improve the confidence of existing diffusion
tube data.
The data collected from the 12 month monitoring cycle (08/06/11 - 08/06/12)
revealed an annual average of 27.3 µg/m3, which was within the 40 µg/m3 air quality
objective for NO2. The remaining 6 months of these data were annualised and
revealed a total concentration of 25.7 µg/m3 for 2012. These results support the 6
months continuous monitoring already recorded within the 2012 USA (NNDC, 2012).
A further DMRB assessment has been undertaken to account for future changes in
average daily traffic levels due to planned housing development in the immediate
area (Sutton, 2012). This successfully shows that there would only be a negligible
impact on existing NO2 concentrations from traffic flow increases, and as such,
justification for an AQMA is unwarranted for the foreseeable future.
The greater degree of confidence provided by continuous monitoring successfully
demonstrates that the Hoveton Hotspot is within the national objective for NOx. In
view of the conclusions drawn from the wider district in respect to air quality and the
fact that the current situation is unlikely to change in the near future, the Council
proposes to cease monitoring within the district and undertake annual review
initiating changes as and when required. At this current time further air quality
monitoring is proposed on the prelude to the 2016 Updating and Screening
Assessment.
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North Norfolk District Council
Table of Contents
1 2 Introduction
5 1.1 Description of Local Authority Area
5 1.2 Purpose of Progress Report
5 1.3 Air Quality Objectives
6 1.4 Summary of Previous Review and Assessments
8 New Monitoring Data
10 2.1 Summary of Monitoring Undertaken
10 2.2 Comparison of Monitoring Results with Air Quality Objectives
15 3 New Local Developments
27 4 Conclusions and Proposed Actions
28 10.1 Conclusions from New Monitoring Data
28 10.2 Conclusions relating to New Local Developments
28 10.3 Other Conclusions
10.4 Proposed Actions
5 Error! Bookmark not defined. References
28 29 List of Tables
1.1
Air Quality Objectives included in Regulations for the purpose of LAQM in England
2.1
Details of Automatic Monitoring Sites
2.2
Details of Non- Automatic Monitoring Sites
2.3
NO2 Trends 2007-12
2.4
Table 2.4 Results of Automatic Monitoring of Nitrogen Dioxide (08/06/11 - 08/06/12):
Comparison with Annual Mean Objective
2.5
Table 2.5 Results of Automatic Monitoring for Nitrogen Dioxide (08/06/11 - 08/06/12):
Comparison with 1-hour Mean Objective
2.6
Table 2.6 Results of Automatic Monitoring of Nitrogen Dioxide 2012: Comparison with Annual
Mean Objective
2.6.1
Diffusion Tube Data Correction
2.6.2
Calculated NO2 Annual Average.
2.7
Results of Automatic Monitoring for Nitrogen Dioxide 2012 Comparison with 1-hour mean
Objective
2.8
Annual Average Diffusion Tube Data Jan 2012 to Dec 2012
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North Norfolk District Council
2.9
Results of NO2 Diffusion Tubes 2012
2.10
Results of NO2 Diffusion Tubes (2008 to 2013)
List of Figures
Figure 1
Map of Hoveton Showing Monitoring Locations.
Figure 2
Map of Monitoring Locations within the Hoveton NO2 Hotspot
Figure 3
24 hour average monitoring data
Appendices
Appendix 1
2012 Diffusion Tube Data
Appendix 2
QA:QC Data
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North Norfolk District Council
1
1.1
Introduction
Description of Local Authority Area
North Norfolk District Council is a large rural Authority covering 550 square miles of
the Norfolk coastline. Due to its location and rural nature, industry is generally small
scale and most of the air pollution is attributed to road traffic.
The main population within North Norfolk is located around the market towns of
Wells-Next-The-Sea, Fakenham, Holt, Sheringham, Cromer, North Walsham, and
Stalham. The population varies significantly between the summer and winter due to
tourism which is a major part of the local economy. The increase in population also
means an increase in the numbers of vehicles and traffic.
Due to the coastal geographic location North Norfolk does not suffer from through
traffic; all traffic is considered locally based.
1.2
Purpose of Progress Report
This report fulfils the requirements of the Local Air Quality Management process as
set out in Part IV of the Environment Act (1995), the Air Quality Strategy for England,
Scotland, Wales and Northern Ireland 2007 and the relevant Policy and Technical
Guidance documents. The LAQM process places an obligation on all local authorities
to regularly review and assess air quality in their areas, and to determine whether or
not the air quality objectives are likely to be achieved. Where exceedences are
considered likely, the local authority must then declare an Air Quality Management
Area (AQMA) and prepare an Air Quality Action Plan (AQAP) setting out the
measures it intends to put in place in pursuit of the objectives.
Progress Reports are required in the intervening years between the three-yearly
Updating and Screening Assessment reports. Their purpose is to maintain continuity
in the Local Air Quality Management process.
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North Norfolk District Council
They are not intended to be as detailed as Updating and Screening Assessment
Reports, or to require as much effort. However, if the Progress Report identifies the
risk of exceedence of an Air Quality Objective, the Local Authority (LA) should
undertake a Detailed Assessment immediately, and not wait until the next round of
Review and Assessment.
1.3
Air Quality Objectives
The air quality objectives applicable to LAQM in England are set out in the Air
Quality (England) Regulations 2000 (SI 928), The Air Quality (England) (Amendment)
Regulations 2002 (SI 3043), and are shown in Table 1.1. This table shows the
objectives in units of microgrammes per cubic metre µg/m3 (milligrammes per cubic
metre, mg/m3 for carbon monoxide) with the number of exceedences in each year
that are permitted (where applicable).
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North Norfolk District Council
Table 1.1
Air Quality Objectives included in Regulations for the purpose of
LAQM in England
Pollutant
Benzene
Air Quality Objective
Concentration
Measured as
Running annual
16.25 µg/m3
mean
Date to be
achieved by
31.12.2003
5.00 µg/m3
Annual mean
31.12.2010
1,3-Butadiene
2.25 µg/m3
Running annual
mean
31.12.2003
Carbon monoxide
10 mg/m3
Running 8-hour
mean
31.12.2003
0.50 µg/m3
0.25 µg/m3
200 µg/m3 not to be
exceeded more
than 18 times a
year
40 µg/m3
50 µg/m3, not to be
exceeded more
than 35 times a
year
40 µg/m3
Annual mean
Annual mean
31.12.2004
31.12.2008
1-hour mean
31.12.2005
Annual mean
31.12.2005
24-hour mean
31.12.2004
Annual mean
31.12.2004
1-hour mean
31.12.2004
24-hour mean
31.12.2004
15-minute mean
31.12.2005
Lead
Nitrogen dioxide
Particulate Matter
(PM10)
(gravimetric)
3
Sulphur dioxide
350 µg/m , not to
be exceeded more
than 24 times a
year
125 µg/m3, not to
be exceeded more
than 3 times a year
266 µg/m3, not to
be exceeded more
than 35 times a
year
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North Norfolk District Council
1.4
Summary of Previous Review and Assessments
North Norfolk District Council has assessed compliance with the National Air Quality
Objectives for all of the pollutants. Previous review and assessment reports have
shown that there is no requirement to monitor Benzene, 1,3 butadiene, Carbon
Monoxide, Lead particulates or Sulphur Dioxide.
The Authority has reviewed this as part of the previous Updating and Screening
Assessment and has determined that there have not been any changes within North
Norfolk or our neighbouring authorities that would indicate that further monitoring is
required.
Since 2002, North Norfolk District Council has undertaken passive diffusion tube
monitoring that indicated an area within the centre of the village of Hoveton in North
Norfolk was close to exceeding the annual mean objective for NO2. This was
identified as a NO2 hotspot and reported through the review and assessment
process.
The hotspot was monitored over the following years, but a further more detailed
assessment was not undertaken as local contributing factors, such as roadwork’s,
were thought to have contributed to the elevated local concentration.
In 2005 it was decided to increase the diffusion tube monitoring around the hotspot to
provide confidence in the data this included the co-location of two tubes together to
act as a quality control and adding a new sampling location on the other side of the
road, just past the junction with Station Road and Church Road.
The decline in concentration that was expected was not observed and, having
reported this in the 2009 Updating and Screening Assessment, it was concluded that
further monitoring would give greater confidence in complying with the National Air
Quality Objective.
In April 2010 a site investigation was undertaken to determine the best method to
gain the required data. The site investigation identified several new diffusion tube
monitoring locations on neighbouring roads which allowed determination of the size
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North Norfolk District Council
of the hot spot but concluded that passive monitoring with diffusion tube would not
provide the confidence in meeting the air quality objective. It was determined that
further monitoring using a continuous NOx analyser would provide the appropriate
data to determine compliance with the National Air Quality Objective.
In Defra’s response to the 2009 Updating and Screening Assessment, it stated that:
“While further action is not required at this stage it may be prudent to consider further
monitoring to provide more data for an assessment and to consider the issues in any
future planning including transport planning”.
Continuous NOx monitoring was successfully initiated in 2011 over a 12 month
period. The first 6 months analysis was reported within the 2012 Updating and
Screening Assessment (NNDC, 2012). Diffusion tube monitoring was continued
during this period to compliment the continuous data.
Continuous monitoring initially indicated that NO2 concentrations would be well within
the annual objective. A Further study was initiated (Sutton, 2012) to account for
future anticipated increases in traffic flow from planned housing developments in the
immediate area. The results of this study concluded that the anticipated increase in
traffic flow would have a negligible impact of future NOx concentrations.
Since submission of the 2012 USA the remaining 6 months of continuous monitoring
data has been recorded providing a full continuous 12 month data set between 2011
and 2012, with a further annualised period of data for 2012. Details of these findings
are specified in the remainder of the document.
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North Norfolk District Council
2
New Monitoring Data
2.1
Summary of Monitoring Undertaken
2.1.1
Automatic Monitoring Sites
In May 2011 a continuous monitoring station was installed in the centre of Hoveton to
gain a continuous NOx data set (Fig 2). The station remained operational between
the 08/07/11 and 08/07/12. The first 6 months of continuous data were recorded and
analysed in the 2012 Updating and Screening Assessment (NNDC, 2012). The final
6 months of continuous data has now been recorded and are included in this
progress report.
The monitoring station comprises a Romon 300, roadside enclosure, housing a
Monitor Europe 9841B NOx Analyser with IZS NOx analyser. The instrument works
on the principle of gas phase chemiluminescence and performs continuous analysis
of nitric oxide (NO), total oxides of nitrogen (NOx), and nitrogen dioxide (NO2). The
instrument has a resolution of 0.5 ppb and a response time of 10 seconds.
The station was decommissioned in June 2012 and no further continuous monitoring
has been undertaken since this time.
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North Norfolk District Council
Table 2.1
Site Name
Hoveton
AQMS
Details of Automatic Monitoring Sites
Site Type
Urban
Roadside
LAQM Progress Report 2013
X OS
GridRef
Y OS Grid
Ref
Pollutants
Monitored
In AQMA?
630392,
318157
NO2
N
Monitoring
Technique
Relevant
Exposure?
(Y/N with
distance
(m) to
relevant
exposure)
Distance to
kerb of
nearest
road
(N/A if not
applicable)
Does this location
represent worstcase exposure?
Y (5m)
3m
Y
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North Norfolk District Council
2.1.2
Non-Automatic Monitoring Sites
As with 2011, diffusion tube monitoring sites were maintained in existing locations
(Figure 1, 2) and were intended to provide a complimentary set of NOx data with the
continuous NOx monitoring cited in section 2.1.1. Unfortunately unforeseen
interference and administrative errors over this period led to the loss of significant
data, with data capture rates as low as 33%. In view of this, the validity of the
annualised 2012 diffusion tube data is questionable.
Fig 1. Map of Hoveton Showing Monitoring Locations.
Background
Hoveton Hotspot
©Crown copyright and database right 2012 Ordinance Survey 100018623
The diffusion tubes, provided and analysed by Gradko International are acrylic tubes
fitted with a coloured cap, covering the absorbent (20% Triethanolamine / De-ionised
Water), at one end and white thermoplastic rubber cap at the exposure end. The
concentrations of nitrite ions and hence NO2 chemically adsorbed are quantitatively
determined by UV/ Visible Spectrophotometry with reference to a calibration curve
derived from the analysis of standard nitrite solutions. (Gradko TDS 1, 2012)
The Defra Local Air Quality Management website publishes data on national diffusion
tube bias factor adjustment which is used to adjust data following a series of colocation studies using continuous monitors co located with diffusion tubes.
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North Norfolk District Council
Fig 2. Map of Monitoring Locations within the Hoveton NO2 Hotspot
Hoveton 3
Hoveton 4
Hoveton 6
Hoveton 10a
Hoveton 10c
Air Quality Station
and Hoveton 1 + 2
Hoveton 5
©Crown copyright and database right 2012 Ordinance Survey 100018623
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North Norfolk District Council
Table 2.2
Site Name
Hoveton 10a
Hoveton 10c
Hoveton 1
Hoveton 2
Hoveton 3
Hoveton 4
Hoveton 5
Hoveton 6
Hoveton 11
Details of Non- Automatic Monitoring Sites
Site Type
Urban
Roadside
Urban
Roadside
AQMS Colocation
AQMS Colocation
Urban
Roadside
Urban
Roadside
Urban
Roadside
Urban
Roadside
Urban
Background
LAQM Progress Report 2013
X OS Grid
Ref
Y OS Grid
Ref
Pollutants
Monitored
In AQMA?
Is
monitoring
collocated
with a
Continuous
Analyser
(Y/N)
630390
318169
NO2
N
N
Y (7m)
3m
Y
630430
318189
NO2
N
N
Y (10m)
3m
Y
630392,
318157
NO2
N
Y
Y (5m)
3m
Y
630392,
318157
NO2
N
Y
Y (5m)
3m
Y
630443
318216
NO2
N
N
Y (15m)
3m
Y
630467
318212
NO2
N
N
Y (20m)
3m
Y
630414
318153
NO2
N
N
Y (15m)
3m
Y
630513
318236
NO2
N
N
Y (7m)
3m
Y
631129
318621
NO2
N
N
Y (3m)
3m
N
Relevant
Exposure?
(Y/N with
distance (m)
to relevant
exposure)
Distance to
kerb of
nearest road
(N/A if not
applicable)
Does this
location
represent
worst-case
exposure?
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North Norfolk District Council
2.2
Comparison of Monitoring Results with Air Quality
Objectives
North Norfolk District Council has met all the National Air Quality Objectives and
there is no requirement to proceed to a detailed assessment for any of the monitored
pollutants.
Nitrogen Dioxide (NO2)
Table 2.3 NO2 Trends 2007- 2012
Hoveton NO2 Diffusion Tube Data - Annual Average 2007 – 2012 (µg/m3)
Hoveton 10a
Hoveton 10b
Hoveton 10c
Hoveton 1
Hoveton 2
Hoveton 3
Hoveton 4
Hoveton 5
Hoveton 6
Hoveton 11
Hoveton AQMS (continuous) 2007
37.09
33.11
34.26
‐ ‐ ‐ ‐ ‐ ‐ 12.26
‐ 2008
38.143
35.413
33.874
‐ ‐ ‐ ‐ ‐ ‐ 14.31
‐ 2009
2010
2011 33.85
45.47
32.07 34.83
44.6
31.83 31.6
44.72
30.5 ‐ ‐ 33.87 ‐ ‐ 34.46 ‐ 56.7
23.21 ‐ 39.03
20.11 ‐ 53.99
27.56 ‐ 32.18
31.52 12.49
20.45
18.07 ‐ ‐ 27.05 2012 47.04 ‐ 37.38 37.96 37.58 28.94 24.95 35.32 41.03 14.70 Mean 38.02 35.96 34.66 33.68 33.81 35.15 27.05 37.57 33.30 15.09 25.74 26.40 Hoveton NO2 Continuous Monitoring Data ‐ 08/06/11 ‐ 08/06/12 (µg/m3) Hoveton AQMS 27.3 *Exceedences are identified in bold
Table 2.3 above illustrates the compiled diffusion tube NO2 data between 2007 and
2012 together with continuous monitoring data for 2011, 2012 and intervening period
2011/12. As previously reported, Table 2.3 illustrates a potential issue with the
diffusion data obtained for years 2010 and 2012. In view of the difficulties
surrounding data collection during these two annual periods, the unusually high
concentrations of NO2 recorded are likely to be attributed to the low level of data
capture. Rather than demonstrating actual increases in NO2 emissions compared to
previous years it was agreed that these results are likely to be a reflection of
insufficient data and the subsequent statistical uncertainties generated from this.
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North Norfolk District Council
The loss of diffusion tube data in 2012 was mitigated by the availability of the
continuous monitoring data from the first 6 months of that year; in view of this a
decision was made not to rely on diffusion tube data.
With the exception of 2010
and 2012, trends in NO2 concentration remain below annual mean objectives.
This conclusion is firmly supported by continuous monitoring, which, using
annualised data, established a mean NO2 concentration of 27.05 µg/m3 in 2011, and
25.74 µg/m3 in 2012. This was further supported by an equivalent annual mean
concentration of 27.3 µg/m3 between 08/06/11 - 08/06/12 (Table 2.3). This data
clearly shows that NO2 concentrations are below the annual mean objective for NO2.
Automatic Monitoring Data
Automatic Monitoring 2011
Continuous monitoring data for the 2011 period has been previously reported in the
2012 USA (NNDC, 2012).
Automatic Monitoring 08/06/11 - 08/06/12
For the purposes of comparing the annual mean objective with the data obtained
from the 08/06/11 - 08/06/12 period, data has been reported as an annual equivalent
as this period does not correspond to a normal calendar year. Comparison to the
annual mean objective and 1 hour mean objective can be examined within table 2.4
and 2.5 respectively. The Oxides of Nitrogen Continuous Hourly Mean Data has also
been provided within Figure 3.
Automatic Monitoring 2012
Annual average data collection in 2012 corresponded to a monitoring period between
January-July with a valid data capture of only 51%. To calculate the annual average
a data correction was used following the procedure set out in Box 3.2 (Estimation of
annual mean concentrations from short-term monitoring data) in the Defra Air Quality
Management Technical Guidance (TG/09).
For the data correction, two sites were selected which were considered to be close
representatives for the sample site (Table 2.6.1). The sites used are Norwich
Lakenfield and Wicken Fen. Comparison to the annual mean objective and 1 hour
mean objective can be examined within table 2.6 and 2.7 respectively.
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North Norfolk District Council
Table 2.4 Results of Automatic Monitoring of Nitrogen Dioxide (08/06/11 - 08/06/12): Comparison with Annual Mean Objective
Site ID
Site Type
Within
AQMA?
Valid Data
Capture for
period of
monitoring %a
Valid Data
Capture
2011/12 % b
Annual Mean
Concentration
μg/m3
2011/12 c
N
94.05
94
27.30
Hoveton Air
Quality
Urban
Monitoring
Roadside
Station
a
i.e. data capture for the monitoring period, in cases where monitoring was only carried out for part of the year.
i.e. data capture for the full calendar year (e.g. if monitoring was carried out for six months the maximum data capture for the full
calendar year would be 50%.)
c
Means should be “annualised” as in Box 3.2 of TG(09), if monitoring was not carried out for the full year.
*Annual mean concentrations for previous years are optional.
b
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North Norfolk District Council
Table 2.5 Results of Automatic Monitoring for Nitrogen Dioxide (08/06/11 - 08/06/12): Comparison with 1-hour mean Objective
Site ID
Site Type
Within
AQMA?
Valid Data
Capture for
period of
monitoring %a
Valid Data
Capture
2011/12 % b
N
94.05
94
Number of Exceedences of
Hourly Mean (200 μg/m3)
2011/12 c
Hoveton Air
Quality
Urban
Monitoring
Roadside
0
Station
a
i.e. data capture for the monitoring period, in cases where monitoring was only carried out for part of the year.
i.e. data capture for the full calendar year (e.g. if monitoring was carried out for six months the maximum data capture for the full
calendar year would be 50%.)
c
If the period of valid data is less than 90%, include the 99.8th percentile of hourly means in brackets
*Number of exceedences for previous years are optional.
b
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North Norfolk District Council
Figure 3. 24 hour average monitoring data
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Table 2.6 Results of Automatic Monitoring of Nitrogen Dioxide 2012: Comparison with Annual Mean Objective
Site ID
Site Type
Within
AQMA?
Valid Data
Capture for
period of
monitoring %a
N
94.05
Annual Mean
Concentration
Valid Data
μg/m3
Capture 2012
%b
2012 c
Hoveton Air
Quality
Urban
Monitoring
Roadside
51.18
25.74
Station
a
i.e. data capture for the monitoring period, in cases where monitoring was only carried out for part of the year.
i.e. data capture for the full calendar year (e.g. if monitoring was carried out for six months the maximum data capture for the full
calendar year would be 50%.)
c
Means should be “annualised” as in Box 3.2 of TG(09), if monitoring was not carried out for the full year.
*Annual mean concentrations for previous years are optional.
b
2.6.1 Diffusion Tube Data Correction
Table 2.6.2 Calculated NO2 Annual Average.
N02 Annual Average Data Correction
Annual
Mean
Norwich Lakenfield
Wicken Fen
LAQM Progress Report 2013
Period
Mean
Ratio
Am/Pm
13.99
16.15
0.87
12.81
12.57
1.02
0.94
Average Ratio
Hoveton continuous Data - NO2 Annual Average
Hoveton Air Quality
Data
Calculated Annual
Station NO2
Calculated
Average (µg/m3)
Concentration (µg/m3)
Correction
Factor
27.3
20
0.94
25.74
North Norfolk District Council
Table 2.7 Results of Automatic Monitoring for Nitrogen Dioxide 2012 Comparison with 1-hour mean Objective
Site ID
Site Type
Within
AQMA?
Valid Data
Capture for
period of
monitoring %a
Valid Data
Capture 2012
%b
N
94.05
51.18
Number of Exceedences of
Hourly Mean (200 μg/m3)
2012 c
Hoveton Air
Quality
Urban
Monitoring
Roadside
0
Station
a
i.e. data capture for the monitoring period, in cases where monitoring was only carried out for part of the year.
i.e. data capture for the full calendar year (e.g. if monitoring was carried out for six months the maximum data capture for the full
calendar year would be 50%.)
c
If the period of valid data is less than 90%, include the 99.8th percentile of hourly means in brackets
*Number of exceedences for previous years are optional
b
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Diffusion Tube Monitoring Data
Diffusion tubes were exposed for between 4 and 8 weeks, between January 2012
and July 2012. In January 2012 Norfolk County Council engaged an energy saving
program including the replacement of all lamp posts within the Hoveton area. This
was to allow them to be turned off between 23.00 and 06.30 thus saving energy.
Unfortunately all the diffusion tube monitoring locations were street lamps and so all
the sample sites were lost and had to be replaced in February 2012 resulting in a
loss of data for these 2 months. In addition to this, administration errors from July
onwards meant that further diffusion analysis was lost for these remaining months.
Monthly data can be seen in Appendix 1. In response to the low levels of data
capture, diffusion tube data obtained for the 2012 period was annualised (Appendix
B), the results of which are presented in table 2.8 below.
Table 2.8 Annual Average Diffusion Tube Data Jan 2012 to Dec 2012
Hoveton NO2 Diffusion Tube Data -Average Jan 2012 to Dec 2012
Bias adjusted (1.02)
3)
Diffusion tube (µg/m
(µg/m3)
46.11
47.04
Hoveton 10a
36.65
37.38
Hoveton 10c
37.21
37.96
Hoveton 1
36.84
37.58
Hoveton 2
28.37
28.94
Hoveton 3
24.46
24.95
Hoveton 4
34.62
35.32
Hoveton 5
40.23
41.03
Hoveton 6
14.41
14.70
Hoveton 11
When comparing the current year’s diffusion tube data with previous years it is clear
that there is a significant issue with the data collected in 2012 and all sites reported
higher levels than other years. In view of the difficulties experienced over this period
the validity of the 2012 data is questionable and therefore no firm conclusions can be
made, however the data also shows a reduction in concentration as you move away
from the hotspot which appears to confirm the assumption that the hotspot
represents a small area of the town centre.
LAQM Progress Report 2013
North Norfolk District Council
Concerns with the 2012 diffusion tube data, although disappointing, are not
considered serious, as the complimentary continuous monitoring data reveals that
actual NO2 concentrations are firmly below annual mean objectives over this period.
LAQM Progress Report 2013
North Norfolk District Council
Table 2.9
Site ID
Hoveton 10a
Hoveton 10c
Hoveton 1
Hoveton 2
Hoveton 3
Hoveton 4
Hoveton 5
Hoveton 6
Hoveton 11
Results of NO2 Diffusion Tubes 2012
Site
Type
N
N
N
N
N
N
N
N
N
Within
AQMA
?
N
N
N
N
N
N
N
N
N
Triplicate
or
Collocated
Tube
N
N
N
N
N
N
N
N
N
Data
Capture
2012
(Number
of Months
or %)
33
42
42
42
42
42
33
25
33
Data with
less than 9
months has
been
annualised
(Y/N)
Y
Y
Y
Y
Y
Y
Y
Y
Y
Confirm if
data has
been
distance
corrected
(Y/N)
N
N
N
N
N
N
N
N
N
Annual mean
concentration
(Bias Adjustment
factor = 1.02)
2012 (μg/m3)
47.04
37.38
37.96
37.58
28.94
24.95
35.32
41.03
14.70
In bold, exceedence of the NO2 annual mean AQS objective of 40µg/m3
Underlined, annual mean > 60µg/m3, indicating a potential exceedence of the NO2 hourly mean AQS objective
a
Means should be “annualised” as in Box 3.2 of TG(09)( http://laqm.defra.gov.uk/technical-guidance/index.html?d=page=38), if full
calendar year data capture is less than 75%
b
If an exceedence is measured at a monitoring site not representative of public exposure, NO2 concentration at the nearest relevant
exposure should be estimated based on the “NO2 fall-off with distance” calculator (http://laqm.defra.gov.uk/tools-monitoring-data/no2falloff.html), and results should be discussed in a specific section. The procedure is also explained in Box 2.3 of Technical Guidance
LAQM.TG(09) (http://laqm.defra.gov.uk/technical-guidance/index.html?d=page=30).
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Table 2.10
Results of NO2 Diffusion Tubes (2008 to 2013)
2007*
Site ID
Hoveton 10a
Hoveton 10c
Hoveton 1
Hoveton 2
Hoveton 3
Hoveton 4
Hoveton 5
Hoveton 6
Hoveton 11
Site Type
Roadside
Roadside
Roadside
Roadside
Roadside
Roadside
Roadside
Roadside
Background
Within
AQMA?
N
N
N
N
N
N
N
N
N
2008*
Annual mean concentration (adjusted for bias) μg/m3
2009*
2010*
2011
2012
(Bias
Adjustment
Factor = 0.89)
(Bias
Adjustment
Factor = 0.92)
(Bias
Adjustment
Factor = 0.90)
(Bias
Adjustment
Factor = 0.92)
(Bias
Adjustment
Factor = 0.90)
(Bias
Adjustment
Factor = 1.02)
37.09
34.26
38.143
33.874
33.85
31.60
45.47
44.72
12.49
56.70
39.03
53.99
32.18
20.45
32.07
30.50
33.87
34.46
23.21
20.11
27.56
31.52
18.07
47.04
37.38
37.96
37.58
28.94
24.95
35.32
41.03
14.70
12.26
14.31
In bold, exceedance of the NO2 annual mean AQS objective of 40µg/m3
Underlined, annual mean > 60µg/m3, indicating a potential exceedence of the NO2 hourly mean AQS objective
a
Means should be “annualised” as in Box 3.2 of TG(09) (http://laqm.defra.gov.uk/technical-guidance/index.html?d=page=38), if full
calendar year data capture is less than 75%
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2.2.1
Summary of Compliance with AQS Objectives
North Norfolk District Council has examined the results from monitoring in the district.
Concentrations are all below the objectives, therefore there is no need to proceed to
a Detailed Assessment.
The Authority has investigated all the pollutants covered within the Air Quality
Strategy in previous review and assessment reports and determined that no further
investigation was require for any of the pollutants with the acceptation of nitrogen
dioxide.
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3
New Local Developments
North Norfolk District Council confirms that there are no new or newly identified local
developments which may have an impact on air quality within the Local Authority
area.
North Norfolk District Council confirms that all the following have been considered:
•
•
•
•
•
Road traffic sources
Other transport sources
Industrial sources
Commercial and domestic sources
New developments with fugitive or uncontrolled sources.
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4
Conclusions and Proposed Actions
4.1
Conclusions from New Monitoring Data
North Norfolk District Council has met all the National Air Quality Objectives and
there is no requirement to proceed to a detailed assessment for any of the monitored
pollutants.
4.2
Conclusions relating to New Local Developments
There are no proposed developments that will have a significant impact on local air
quality.
4.3
Proposed Actions
In view of the degree at which concentrations are below the NO2 air quality objective
the Council has decided to terminate annual diffusion tube and continuous monitoring
activities in the Hoveton area and proposes to review the exiting situation on an
annual basis, taking into consideration wider changes within the district and
undertaking further analysis as and when required. Further air quality monitoring will
be undertaken on the prelude to the Updating and Screening Assessment in 2016 to
identify and trend changes in NO2 concentration.
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5
References
1. DEFRA (2009), Part IV of the Environment Act 1995, Local Air Quality
Management (2009), Policy Guidance LAQM. PG (09). DEFRA
2. DEFRA (2009), Part IV of the Environment Act 1995, Local Air Quality
Management (2009), Technical Guidance LAQM. TG (09). DEFRA
3. DEFRA (2010) Air Pollution in the UK 2010, DEFRA
4. HM Government 2000, The Air Quality (England) Regulations 2000. Statutory
Instruments 2000 No. 928, The Stationery Office Ltd, London (2000)
5. HM Government 2002, The Air Quality (England) (Amendment) Regulations
2002. Statutory Instruments 2002 No. 3043
6. North Norfolk District Council, Updating and Screening Assessment, Air
Quality Progress report 2009, North Norfolk District Council
http://www.northnorfolk.org/files/TDEPAQ05B_Air_Quality_Report_2009.pdf
7. North Norfolk District Council, Updating and Screening Assessment, Air
Quality Progress report 2012, North Norfolk District Council
http://www.northnorfolk.org/files/TDEPAQ05B_Air_Quality_Report_2010.pdf
8. Sutton 2012, An Investigation into the current and potential future levels of
Nitrogen Dioxide in Hoveton Norfolk.
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Appendices
Appendix A: 2012 monitoring Data
Appendix B: Quality Assurance / Quality Control (QA/QC) Data
Appendix A: 2012 Diffusion Tube Data
Hoveton 6
Jan ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Feb ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Mar 41.62 37.65 38.98 32.43 28.27 23.79 38.12 ‐ Apr ‐ 28.46
33.4
31.17
24.77
23.3
37.53
35.19
May 39.2
35.09
30.13
31.56
28.29
20.18
21.38
31.23
June 30.86
25.91
26.52
29.3
18.04
17.84
26.6
25.59
Hoveton 11
‐ ‐ ‐ 21.67
8.12
5.98
Hoveton 10a
Hoveton 10c
Hoveton 1
Hoveton 2
Hoveton 3
Hoveton 4
Hoveton 5
July 40.63
29.85
30.36
33.35
22.14
18.26
‐ ‐ Aug ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ 7.59 ‐ Sept ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Oct ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Nov ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Dec ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ ‐ Appendix B: QA:QC Data
Diffusion Tube Bias Adjustment Factors
The Bias factor used was 1.02 and obtained using the spread sheet supplied by the
National Air Quality Review and Assessment Website. In order to obtain an
appropriate bias adjustment factor the following information was used
Laboratory that supplied the diffusion tubes: Gradko International
Preparation method: 50% TEA in Acetone.
http://www.uwe.ac.uk/aqm/review/R&Asupport/diffusiontube310310.xls
Discussion of Choice of Factor to Use
See above
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Short-term to Long-term Data adjustment
Lakenfields Wicken Fen Annual Period Annual Period Average Location Ref Mean Mean Ratio Mean Mean Ratio Ratio Hoveton 10a 14.26 13.94
1.02
12.82
9.16
1.40 1.21
Hoveton 10c 14.26 14.47
0.99
12.82
9.50
1.35 1.17
Hoveton 1 14.26 14.47
0.99
12.82
9.50
1.35 1.17
Hoveton 2 14.26 14.47
0.99
12.82
9.50
1.35 1.17
Hoveton 3 14.26 14.47
0.99
12.82
9.50
1.35 1.17
Hoveton 4 14.26 14.03
1.02
12.82
9.50
1.35 1.18
Hoveton 5 14.26 15.11
0.94
12.82
9.88
1.30 1.12
Hoveton 6 14.26 13.21
1.08
12.82
8.30
1.54 1.31
Hoveton 11 14.26 12.89
1.11
12.82
8.26
1.55 1.33
Annualised data regarding the reference locations in the table above were obtained
using data from long term monitoring sites at Lakenfields and Wicken Fen.
QA/QC of Automatic Monitoring
The Hoveton Air Quality Management Stations is maintained and serviced under
contract by the supplier, Casella Measurement. Casella undertake 6 month
calibrations along with service and maintenance. They also undertake any callout
maintenance work.
Casella Measurement also maintains the data and undertakes the quality control
Casella Measurement Procedure
• Re-scaling. Officers of North Norfolk District Council or ‘Local Site Operator’ (LSO)
providing fortnightly calibration reports as a result of using calibration sources
such as gas cylinders and zero air scrubbers. This data is used to calculate the
true analyser zero and response factor and is used to scale data for the following
two weeks leading up to the next scheduled LSO Visit. When re-scaling, both a
short term and long term view should be taken. For instance, the scaling factors
from two consecutive LSO visits may be different; is this to be considered as long
term linear analyser drift or did a step change occur in the analyser’s response
since the last visit? If a step change occurred then we need to know when and
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consider how the data should be treated; this is where daily auto calibrations
become very useful. Zero data may also be reviewed on a daily basis so that the
most appropriate value is applied.
• Data Validation is a check of the data trend to ensure that there are no obvious
errors such as spikes or un-flagged calibration checks. Cases of severe trend
drifting may also trigger an investigation to ascertain if an analyser is at fault or if
a local event such as road works is causing the response. Not all cases will result
in deletion of data.
• The second stage of data correction is known as ‘Ratification’ and requires the
results of a QA/QC audit on the analysers and Air Quality Station.
QA/QC of Diffusion Tube Monitoring
The Workplace Analysis Scheme for Proficiency (WASP) is an independent analytical
performance-testing scheme, operated by the Health and Safety Laboratory (HSL).
WASP forms a key part of the former UK nitrogen dioxide networks QA/QC, and
remains an important QA/QC test for laboratories supplying diffusion tubes to Local
Authorities. Participants in the scheme analyse four spikes tubes, and report the
results to the HSL. Performance scores are allocated to each laboratory dependent
upon the reported results.
The outcome of the WASP scheme is evaluated on a regular basis against a set of
pre-defined performance criteria. The performance criteria are based on the Rolling
Performance Index (RPI) statistic
Gradko Laboratories takes part in the WASP scheme for the analysis of nitrogen
dioxide diffusion tubes and demonstrated good performance between January 2012
and July 2012.
Results for the corresponding WASP round, R116 & R117 showed all results as
satisfactory, see table below:
Table 2.12 Wasp results for corresponding period of monitoring (Jan 2012‐July 2012) WASP Round Round conducted in the period Gradko International [2] WASP R113 April ‐ June 2011 100 % WASP R114 July ‐ September 2011 100 % WASP R115 October ‐ December 2011 37.5 % WASP R116 January – March 2012 100 % WASP R117 April – June 2012 100 % WASP R118 July – September 2012 100 % WASP R119 October – December 2012 100 % WASP R120 January – March 2013 100 % LAQM Progress Report 2013
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The following table lists those UK laboratories undertaking LAQM activities that have participated in recent HSL WASP NO2 PT rounds and the percentage (%) of results submitted which were subsequently determined to be satisfactory based upon a z‐score of <± 2 as defined above. LAQM Progress Report 2013
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