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SUMMARY:Urban street canyons: Coupling dynamics\, chemistry and within-can
 yon chemical processing of emissions/Low-cost Sensors for Air Quality Moni
 toring: Personal Exposure Studies and High Density Network for Air Quality
  Assessment - Dr Vivien Bright/Dr Olalekan Popoola (University of Cambridg
 e)
DTSTART:20130513T131500Z
DTEND:20130513T143000Z
UID:TALK41912@talks.cam.ac.uk
CONTACT:Dr Amanda Maycock
DESCRIPTION:Dr Vivien Bright\nUrban street canyons: Coupling dynamics\, ch
 emistry and within-canyon chemical processing of emissions.\n\nAtmospheric
  composition within the urban environment\, particularly within street can
 yons (formed by a road running between two rows of buildings)\, has a dire
 ct effect on the air quality of an environment in which a large majority o
 f people live and work. The composition of air within a street canyon is d
 etermined by the composition of background air mixed in from above\, advec
 tion of air into and out of the canyon\, vehicle exhaust and other emissio
 ns from within the street\, together with the mixing and chemical processi
 ng of pollutants within the canyon. This occurs on a timescale of a few se
 conds to minutes and as a result\, within-canyon atmospheric processes can
  have a significant effect on atmospheric composition on such timescales.\
 n\nThis paper outlines the results of a modelling study of composition on 
 the street canyon scale\, integrating the combined effects of emissions\, 
 dynamics and chemistry. The work builds upon an existing dynamical model o
 f canyon atmospheric motion (Large Eddy Simulation (LES) model) by adding 
 a detailed chemical reaction scheme. Previous studies have considered basi
 c NOX-O3 cycles with only a small number of chemical reactions included.  
 \n\nInitially\, a zero-dimensional box model was used to develop and asses
 s the accuracy of a suitable reduced chemical scheme to be included within
  the LES. The reduced chemical scheme\, based upon a subset of the Master 
 Chemical Mechanism (MCM)\, includes 51 chemical species and 136 reactions.
  Vehicle emissions taken from the UK National Atmospheric Emissions Invent
 ory (NAEI) were subsequently added to the box model. These elements were t
 hen combined with the canyon dynamics simulated by the Large Eddy Simulati
 on (LES) model. Previous work demonstrates that the enhanced model is a su
 itable tool to be used to further investigate the combined effects of mixi
 ng and chemical processing upon air quality within the street canyon.\n\nN
 ext speaker\n\nDr Olalekan Popoola\n\nLow-cost Sensors for Air Quality Mon
 itoring: Personal Exposure Studies and High Density Network for Air Qualit
 y Assessment\n\nOutdoor air quality and its impact on human health and the
  environment have been well studied and it has been projected that poor ai
 r quality will surpass poor sanitation as the major course of environmenta
 l premature mortality by 2050 (IGAC / IGBP\, release statement\, 2012). Tr
 ansport-related pollution has been regulated at various levels by enactmen
 t of legislations at local\, national\, regional and global stages. As par
 t of the mitigation measures\, routine measurements of atmospheric polluta
 nts such as carbon monoxide (CO)\, nitric oxide (NO) and nitrogen dioxide 
 (NO2) have to be established in areas where air quality problems are ident
 ified. In addition\, emission inventories are also generated for different
  atmospheric environments including urban areas and airport required for a
 ir quality models.\n\nWhilst recognising that most of the existing monitor
 ing networks provide high temporal measurements\, spatial distribution of 
 these often variable pollutants are not captured\, making it difficult to 
 adequately characterise the highly heterogeneous air quality. Spatial info
 rmation is often obtained from model data which can only be constrained us
 ing measurements from the sparse monitoring networks.\n\nThe work presente
 d here shows the application of low-cost electrochemical sensor networks i
 n monitoring road transport pollutants including CO\, NO and NO2 in an urb
 an environment. Results from personal exposure studies involving short-ter
 m (few  hours) field deployments in four different cities including Cambri
 dge (UK)\, London (UK)\, Valencia (Spain) and Lagos (Nigeria) are presente
 d. In addition\, long-term studies (2.5 months) involving a network of 46 
 static sensor nodes of in Cambridge will also be presented. \n\nCurrent wo
 rk involves a new generation of these instruments which include additional
  species such as O3\, SO2\, VOCs and CO2 as well as size-speciated particu
 lates (0.38 to 17.4 µm). These are currently deployed at London Heathrow 
 Airport (LHR) as part of the Sensor Networks for Air Quality at London Hea
 throw (SNAQ-Heathrow) project. Meteorological data such as temperature\, r
 elative humidity\, wind speed and direction are also measured. The network
  will consist of 50 sensor nodes\, deployed in and around the airport peri
 meter. Early results from the SNAQ-Heathrow are presented. These include: 
 examples of regional pollution events influenced by meteorology\, as well 
 as localised pollution effects related to aircraft taxiing\, take-off and 
 landing at the airport\, in addition to other sources e.g. roads in close 
 proximity to the airport. 
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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