A study of pollutant concentration variability in an urban street under low wind speeds

Martin, Damien; Price, C. S.; White, Iain R.; Nickless, G.; Dobre, Adrian; Shallcross, Dudley E.

doi:10.1002/asl.184

Cited by 20 publications

(20 citation statements)

References 46 publications

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“…Overnight on Saturday the expected traffic peak due to night life associated traffic is not observed due to high wind speeds (e.g. Martin et al, 2008). The effects of both wind speed and temperature on H 2 and CO observations are shown in Fig.…”

Section: Diurnal Variationsmentioning

confidence: 98%

High-frequency urban measurements of molecular hydrogen and carbon monoxide in the United Kingdom

et al. 2010

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Abstract. High-frequency measurements of atmospheric molecular hydrogen (H 2 ) and carbon monoxide (CO) were made at an urban site in the United Kingdom (UK) from mid-December, 2008 until early March, 2009. Very few measurements of H 2 exist in the urban environment, particularly within the UK, but are an essential component in the assessment of anthropogenic emissions of H 2 and to a certain extent CO. These data provide detailed information on urban time-series, diurnal cycles as well as sources and sinks of both H 2 and CO at urban locations. High-frequency data were found to be strongly influenced by local meteorological conditions of wind speed and temperature. Diurnal cycles were found to follow transport frequency very closely due to the sites proximity to major carriageways, consequently a strong correlation was found between H 2 and CO mole fractions. Background subtracted mean and rush hour molar H 2 /CO emission ratios of 0.53±0.08 and 0.57±0.06 respectively, were calculated from linear fitting of data. The scatter plot of all H 2 and CO data displayed an unusual two population pattern, thought to be associated with a large industrial area 85 km to the west of the site. However, the definitive source of this two branch pattern could not be fully elucidated. H 2 emissions from transport in the UK were estimated to be 188±39 Gg H 2 /yr, with 8.1±2.3 Tg/yr of H 2 produced from vehicle emissions globally. H 2 and CO deposition velocities were calculated during stable night-time inversion events when a clear decay of both species was observed. CO was found to have a much higher deposition velocity than H 2 , 1.3±0.8×10 −3 and 2.2±1.5×10 −4 m s −1 (1σ ) respectively, going against the law of molecular diffusivity. The source of this unusual result was investigated, however no conclusive explanation was found for increased loss of CO over H 2 during stable night time inversion events.

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Section: Diurnal Variationsmentioning

confidence: 98%

High-frequency urban measurements of molecular hydrogen and carbon monoxide in the United Kingdom

et al. 2010

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“…The early London experiments formed part of the Engineering and Physical Sciences Research Council (EPSRC), United Kingdom-funded Dispersion of Air Pollution and its Penetration into the Local Environment (DAPPLE) project, which ran from 2002 to 2006. Further information can be found on the DAPPLE Web site (www.dappiJ.org.uk), which includes • many reports, videos, figures, maps, and text; but, in short, EPSRC-DAPPLE concentrated chiefly on personal human exposure to traffic pollutants (Arnold et al 2004;Colvile et al 2004), the effects of traffic and street layout on environmental turbulent flow within street canyons (Dobre et al 2005), and both fixed-and moving-source tracer dispersion experiments (Arnold et al 2004;Martin et al 2008). The EPSRC-DAPPLE studies did not yield a sufficiently extensive database of tracer dispersion experiments that could be used unambiguously for evaluating modeling techniques or for probing in detail the dispersion processes and their variability.…”

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confidence: 99%

“…In particular, the loss of tracer to the flow above roof level, and the subsequent dispersion in the boundary layer, will be investigated by wind tunnel and largeeddy simulation (LES) computational fluid dynamics (CFD) modeling. Rooftop release and measurements of tracer have been conducted in previous DAPPLE work, which indicated well-mixed conditions within the street canyons (Martin et al 2008).…”

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Dispersion Experiments in Central London: The 2007 DAPPLE project

Wood¹,

Arnold²,

Balogun³

et al. 2009

Bull. Amer. Meteor. Soc.

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“…Typical atmospheric background concentrations for the most commonly used perfluorocarbons in tracer experiments are in the low ppqv range Kim et al, 2002;Watson et al, 2007) and the current growth rate is, if any growth rate at all, less than 1 ppqv per year (Watson et al, 2007). These compounds have been used previously in dispersion experiments ranging from long range studies (Draxler et al, 1991;Straume et al, 1998) down to city and neighbourhood scales Martin et al, 2008;Martin et al, 2010a, b;Shallcross et al, 2009;Wood et al, 2009). …”

Section: Techniquementioning

confidence: 99%

Tracer concentration profiles measured in central London as part of the REPARTEE campaign

et al. 2011

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Abstract. There have been relatively few tracer experiments carried out that have looked at vertical plume spread in urban areas. In this paper we present results from two tracer (cyclic perfluorocarbon) experiments carried out in 2006 and 2007 in central London centred on the BT Tower as part of the REPARTEE (Regent's Park and Tower Environmental Experiment) campaign. The height of the tower gives a unique opportunity to study vertical dispersion profiles and transport times in central London. Vertical gradients are contrasted with the relevant Pasquill stability classes. Estimation of lateral advection and vertical mixing times are made and compared with previous measurements. Data are then compared with a simple operational dispersion model and contrasted with data taken in central London as part of the DAPPLE campaign. This correlates dosage with non-dimensionalised distance from source. Such analyses illustrate the feasibility of the use of these empirical correlations over these prescribed distances in central London.

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A study of pollutant concentration variability in an urban street under low wind speeds

Cited by 20 publications

References 46 publications

High-frequency urban measurements of molecular hydrogen and carbon monoxide in the United Kingdom

High-frequency urban measurements of molecular hydrogen and carbon monoxide in the United Kingdom

Dispersion Experiments in Central London: The 2007 DAPPLE project

Tracer concentration profiles measured in central London as part of the REPARTEE campaign

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