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Titel |
Low-cost Sensor Networks for Improving Understanding of Urban Air Pollution |
VerfasserIn |
Gregor Stewart, Iq Mead, Olalekan Popoola, Mark Calleja, Mark Hayes, John Saffell, Peter Landshoff, Rod Jones |
Konferenz |
EGU General Assembly 2011
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 13 (2011) |
Datensatznummer |
250054020
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Zusammenfassung |
High-frequency measurements of nitrogen monoxide (NO), nitrogen dioxide (NO2) and
carbon monoxide (CO) were made using a dense network of electrochemical sensors at urban
sites in Cambridge from March – June 2011, with the aim to improve understanding of the
behaviour of these species on fine spatial and temporal scales.
E.U. legislation has set target levels for gases thought to have adverse impacts on human
health, and consequently led to a need for a more informed air pollution control policy. With
many sites in the U.K. and in the rest of the E.U. still failing to meet annual targets for NO2, a
need to better understand pollutant sources and behaviour has arisen. Whilst traditional
chemiluminescence techniques used by local authorities to measure NOx provide great
accuracy, the instrumentation is expensive and difficult to deploy on a dense spatial
scale.
The ability of low-cost, portable devices, incorporating electrochemical sensors to
measure gases such as CO, NO and NO2 at ambient concentrations, with GPS and
GPRS facilities for positioning and data transmission, has been demonstrated by
deployments in urban areas including London, Valencia, Kuala Lumpur and Lagos. Tests in
the laboratory against gas standards at parts-per-billion levels have shown high
sensitivity of the sensors to their respective target gases. Moreover, co-locations in the
field with chemiluminescence and spectroscopic instruments have demonstrated
good agreement. The degree of variability in concentrations of the pollutants, on
both spatial and temporal scales, has been highlighted in the various mobile sensor
campaigns, exposing the limitations of a sparsely populated static network in an urban
centre.
The technology described was extended to establish a dense urban network of
autonomous static units, capable of capturing data with high temporal resolution for several
months. Preliminary results highlight the importance of meteorology, traffic and street
architecture on the levels of pollutants observed. Bivariate polar plots are one type of tool
being used to analyse the data, with the potential to distinguish local and long-range
sources from each other, and to indicate where street canyon recirculation may be
occurring.
Future work will include use of the same static units for an intensive three month
collaboration in London, leading to comparison of data with model results and thus indicating
the effectiveness of part-pedestrianisation of a busy street on mitigating the poor air
quality. Installation of a network of sensors in the grounds of a major international
airport for up to a year will enable source attribution studies to be carried out on a
finer spatial and temporal scale than has been possible before, and allow future
air quality modelling to be carried out more accurately. Furthermore, improved
understanding of the atmospheric science in the vicinity of the airport will mean that
more informed planning decisions can be made in order to ensure that future airport
operations are conducted whilst conforming to acceptable environmental standards. |
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