Twenty years of continuous high time resolution volatile organic compound monitoring in the United Kingdom from 1993 to 2012

Derwent, R.G.; Dernie, J.; Dollard, G. J.; Dumitrean, P.; Mitchell, Robert F.; Murrells, Timothy P.; Telling, S.; Field, Robert A.

doi:10.1016/j.atmosenv.2014.10.001

Cited by 24 publications

(21 citation statements)

References 11 publications

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“…VOC concentrations were approximated by applying representative VOC : benzene ratios for the UK urban environment (Derwent et al, 2000) and applying those to a typical urban UK benzene : CO ratio (Derwent et al, 1995), where CO was measured at the Whitworth observatory. The VOC : benzene ratios are scaled to the year of this study to best approximate ambient levels (Derwent et al, 2014). The calculated benzene : CO ratio is in good agreement with a Non-Automatic Hydrocarbon Network monitoring site (Manchester Piccadilly) approximately 1.5 km from the measurement location, indicating that the approximation made here is reasonably accurate.…”

Section: Radical Budget Calculationsmentioning

confidence: 62%

“…Numerous heterogeneous formation mechanisms leading to Cl 2 from particles containing Cl − are known. These include the reaction of Cl − and OH (Vogt et al, 1996), which may originate from the photolysis of O 3(aq) (Oum, 1998) or from the reactive uptake of ClNO 2 (Leu et al, 1995), ClONO 2 (Deiber et al, 2004) or HOCl (Eigen and Kustin, 1962) to acidic Cl − containing particles. Thornton et al (2010) also suggest that inorganic Cl reservoirs such as HOCl and ClONO 2 may also enhance the Cl concentration, potentially accounting for the shortfall in the global burden (8-22 Tg yr −1 source from ClNO 2 and 25-35 Tg yr −1 as calculated from methane isotopes).…”

Section: Introductionmentioning

confidence: 99%

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Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

et al. 2018

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A number of inorganic (nitryl chloride, ClNO 2 ; chlorine, Cl 2 ; and hypochlorous acid, HOCl) and chlorinated, oxygenated volatile organic compounds (ClOVOCs) have been measured in Manchester, UK during October and November 2014 using time-of-flight chemical ionisation mass spectrometry (ToF-CIMS) with the I − reagent ion. ClOVOCs appear to be mostly photochemical in origin, although direct emission from vehicles is also suggested. Peak concentrations of ClNO 2 , Cl 2 and HOCl reach 506, 16 and 9 ppt respectively. The concentrations of ClNO 2 are comparable to measurements made in London, but measurements of ClOVOCs, Cl 2 and HOCl by this method are the first reported in the UK. Maximum HOCl and Cl 2 concentrations are found during the day and ClNO 2 concentrations remain elevated into the afternoon if photolysis rates are low. Cl 2 exhibits a strong dependency on shortwave radiation, further adding to the growing body of evidence that it is a product of secondary chemistry. However, night-time emission is also observed. The contribution of ClNO 2 , Cl 2 and ClOVOCs to the chlorine radical budget suggests that Cl 2 can be a greater source of Cl than ClNO 2 , contributing 74 % of the Cl radicals produced on a high radiant-flux day. In contrast, on a low radiant-flux day, this drops to 14 %, as both Cl 2 produc-tion and loss pathways are inhibited by reduced photolysis rates. This results in ClNO 2 making up the dominant fraction (83 %) on low radiant-flux days, as its concentrations are still high. As most ClOVOCs appear to be formed photochemically, they exhibit a similar dependence on photolysis, contributing 3 % of the Cl radical budget observed here.

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Section: Radical Budget Calculationsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

et al. 2018

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“…Hourly measured mixing ratios of CO, NO, and NO 2 for 1989–2015 (Figure S4 and Table S1) were obtained from the UK National Air Quality Archive for 17 stations in London [ Dollard et al ., ; von Schneidemesser et al ., ; Derwent et al ., ]. Remote sensing NO x and CO emission measurements of almost 70,000 vehicles are available from a system deployed at four locations in London in 2012 [ Carslaw and Rhys‐Tyler , ], identical to the system employed in the U.S. by Bishop and Stedman [].…”

Section: Methodsmentioning

confidence: 99%

Analysis of long‐term observations of NO_x and CO in megacities and application to constraining emissions inventories

Haßler

McDonald

Frost

et al. 2016

Geophysical Research Letters

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Long‐term atmospheric NOx/CO enhancement ratios in megacities provide evaluations of emission inventories. A fuel‐based emission inventory approach that diverges from conventional bottom‐up inventory methods explains 1970–2015 trends in NOx/CO enhancement ratios in Los Angeles. Combining this comparison with similar measurements in other U.S. cities demonstrates that motor vehicle emissions controls were largely responsible for U.S. urban NOx/CO trends in the past half century. Differing NOx/CO enhancement ratio trends in U.S. and European cities over the past 25 years highlights alternative strategies for mitigating transportation emissions, reflecting Europe's increased use of light‐duty diesel vehicles and correspondingly slower decreases in NOx emissions compared to the U.S. A global inventory widely used by global chemistry models fails to capture these long‐term trends and regional differences in U.S. and Europe megacity NOx/CO enhancement ratios, possibly contributing to these models' inability to accurately reproduce observed long‐term changes in tropospheric ozone.

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“…Therefore, from 1999-2001-2012 there was a change in the balance between emissions of isopentane and toluene and their photochemical removal to the point where photochemical depletion dominated during the day, and VOC / ethane ratios were lower in the afternoon than at night. Derwent et al (2014) calculated exponential decreases in the concentrations of these VOCs at urban locations in the south-east of England, where Harwell is located, attributed to the effective control of evaporative and exhaust emissions from petrol-engine vehicles. Toluene has an atmospheric lifetime of ∼ 1.9 days with respect to reaction with OH (Atkinson, 2000), so local daytime toluene emissions would not deplete substantially during transport to the monitoring site.…”

Section: State: Voc Concentration and Chemical Depletionmentioning

confidence: 99%

The impact of speciated VOCs on regional ozone increment derived from measurements at the UK EMEP supersites between 1999 and 2012

et al. 2015

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Abstract. The impact of 27 volatile organic compounds (VOCs) on the regional O 3 increment was investigated using measurements made at the UK EMEP supersites Harwell (1999Harwell ( -2001Harwell ( and 2010Harwell ( -2012 and Auchencorth (2012). Ozone at these sites is representative of rural O 3 in southeast England and northern UK, respectively. The monthlydiurnal regional O 3 increment was defined as the difference between the regional and hemispheric background O 3 concentrations, respectively, derived from oxidant vs. NO x correlation plots, and cluster analysis of back trajectories arriving at Mace Head, Ireland. At Harwell, which had substantially greater regional O 3 increments than Auchencorth, variation in the regional O 3 increment mirrored afternoon depletion of anthropogenic VOCs due to photochemistry (after accounting for diurnal changes in boundary layer mixing depth, and weighting VOC concentrations according to their photochemical ozone creation potential). A positive regional O 3 increment occurred consistently during the summer, during which time afternoon photochemical depletion was calculated for the majority of measured VOCs, and to the greatest extent for ethene and m+p-xylene. This indicates that, of the measured VOCs, ethene and m+p-xylene emissions reduction would be most effective in reducing the regional O 3 increment but that reductions in a larger number of VOCs would be required for further improvement.The VOC diurnal photochemical depletion was linked to anthropogenic sources of the VOC emissions through the integration of gridded anthropogenic VOC emission estimates over 96 h air-mass back trajectories. This demonstrated that one factor limiting the effectiveness of VOC gridded emissions for use in measurement and modelling studies is the highly aggregated nature of the 11 SNAP (Selected Nomenclature for Air Pollution) source sectors in which they are reported, as monthly variation in speciated VOC trajectory emissions did not reflect monthly changes in individual VOC diurnal photochemical depletion. Additionally, the major VOC emission source sectors during elevated regional O 3 increment at Harwell were more narrowly defined through disaggregation of the SNAP emissions to 91 NFR (Nomenclature for Reporting) codes (i.e. sectors 3D2 (domestic solvent use), 3D3 (other product use) and 2D2 (food and drink)). However, spatial variation in the contribution of NFR sectors to parent SNAP emissions could only be accounted for at the country level. Hence, the future reporting of gridded VOC emissions in source sectors more highly disaggregated than currently (e.g. to NFR codes) would facilitate a more precise identification of those VOC sources most important for mitigation of the impact of VOCs on O 3 formation.In summary, this work presents a clear methodology for achieving a coherent VOC, regional-O 3 -impact chemical climate using measurement data and explores the effect of limited emission and measurement species on the understanding of the regional VOC contribution to O 3 concentrat...

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Twenty years of continuous high time resolution volatile organic compound monitoring in the United Kingdom from 1993 to 2012

Cited by 24 publications

References 11 publications

Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

Analysis of long‐term observations of NO_x and CO in megacities and application to constraining emissions inventories

The impact of speciated VOCs on regional ozone increment derived from measurements at the UK EMEP supersites between 1999 and 2012

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Twenty years of continuous high time resolution volatile organic compound monitoring in the United Kingdom from 1993 to 2012

Cited by 24 publications

References 11 publications

Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

Observations of organic and inorganic chlorinated compounds and their contribution to chlorine radical concentrations in an urban environment in northern Europe during the wintertime

Analysis of long‐term observations of NOx and CO in megacities and application to constraining emissions inventories

The impact of speciated VOCs on regional ozone increment derived from measurements at the UK EMEP supersites between 1999 and 2012

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Analysis of long‐term observations of NO_x and CO in megacities and application to constraining emissions inventories