Rob Kinnersley - Academia.edu (original) (raw)
Papers by Rob Kinnersley
Aerial application of insecticides is likely to remain an important component in realistically-co... more Aerial application of insecticides is likely to remain an important component in realistically-costed vector and migratory pest control operations for the foreseeable future. The objective of this work was to identify or design improved atomisers for use in two such operations, tsetse (Glossina sp.) and African armyworm (Spodoptera exempta) control, the former requiring an insecticide aerosol ýx'ith a VMD of 20 to 30ýim at rates upto 0.5 litres/minute and the latter a fine spray with a VMD of 80 to 120ýtm at rates around 16 litres/minute. In both cases rotary atomisation was confirmed as the most appropriate technique. Assessments were made of seven commerciall%, available atomisers and two existinc, prototypes, on the basis of existing reports and new data generated under simulated flight conditions in a wind tunnel. Droplet sizing was carried out using an optical array probe set to give a resolution of 54m over a range of 3.6-3) 12.54m. None of the atomisers tested met the specification for tsetse-spraying, the limiting factors being rotation speed and inability to distribute low volumes of liquid across their full atomising surface. The Micronair AU4000 and AU5000 and the Micron X-I were found to be suitable for armyworm control, the Micron X-1 having the additional ability to produce spray with VMDs down to 40ýim. A review of rotary atomiser literature provided design guidelines for the design of an atomiser capable of meeting tsetse specifications. The principle effect of liquid flow 4D within the atomiser was found to be on the uniformity of fluid distribution. Premature ligament formation and formation of cross-flow vortices were identified 415-ligament occured at a Weber number of between 4 and 5, similar to reported values for liquid jets in a cross flo%v of cyas. Droplet sizing indicated that the specified performance for tsetse operations could be obtained from 50mm diameter atomisers with a total of around _'30000 issuing points at a rotation speed of 26000 RPNI. This Zý sucy(yested cN, lindcr rather than disc-based atomisers. A slit was found to be impractical as a means of distributing liquid unifom-ily at high rotation speeds but distribution was sucý: essfully achieved using a porous flow resistor. Prototype wind-and electi-ically-driven atornisers were constructed using In particular I am indebted to the following: My supervisor, Steve Parkin, for his guidance, for "giving me my head", and for his reassuring knack of putting things in perspective whenever I felt panic setting in. Professor John Spillman, originally my co-supervisor, for his enthusiastic interest in the project long after his official involvement ceased, and for staying on the right side Oust) of the thin line between mentor and tormentor when it came to the Hard Sums. The incomparable John Wyatt. Optical, mechanical or electronic, he could always make things work and always found the time to do so. Derek Giles, for teaching me how things are made and for turning my naively optimistic drawings into finely crafted reality. Also Paul, Malcolm, Barry, Wayne and Trevor, for their help and their good-humoured tolerence. The gentlemen of the Natural Resources Institute-Cliff Lee, Reg Allsopp, Don Johnstone, Jerry Cooper, Hans Dobson, Francesca Casci and Rob Fenn, for advice, invaluable discussions and words of encouragement. Also for some jolly evenings in Harare and for showing me how to hunt scorpions. The staff of ICAP, particularly Ian Outrarn for many hours of entertainment, and my friend and colleague Neil Morgan, who taught me humility on the electronic golf course. My current employers, for their support whilst writing this thesis, and especially Margaret Minski for preferring the carrot to the stick. The other people, too numerous to mention, whose brains I have picked over the years. My venerable parents. Bemused they may have been by it all but not once did they tell me it was "time I got myself a proper job. Above all I am grateful to Joanne for her love and support over the last few years. subscripts: air liquid radial List of Figures 2.1 Schematic diagram of the optical system of the PMS OAP-26OX 2.2 Schematic diagram of the optical system of the PMS FSSP-100 4.1 Schematic plan view of the Cranfield aerial atomiser test facility 4.2 The Unirot-4 atomiser 4.3 The Beecomist 360A atorniser 4.4a The feed system of the Beecomist 360A emitting water at low flowrate 4.4b The feed system of the Beecomist 360A emitting water at high flowrate 4.5a The feed system of the Micron X-15 emitting Glossinex at 0.2 litres/minute 4.5b The modified Micron X-15 feed system emitting Glossinex at 0.2 litres/minute 4.6 The Micronair AU4000 atomiser 4.7 The Micronair AU5000 atomiser 4.8 The Micron X-1 atomiser 5.1 Stages in atornisation from a rotary atomiser 6.1a Components of the disc observation system 6.1b Circuit diagram of the strobe/spark trigger 6.2 The spark photography system 6.3 Spiral vortices forming in liquid flowing over a 100mm diameter rotating disc 6.4 Trial ligament generators of type TR 1 6.5 Trial ligament generator TR3 6.6 Erratic separation of liquid ligaments from TR3 6.7 Trial ligament generator TR4 6.8 Trial ligament generator TR5 6.9 Liquid escaping from the groove in TR5 6.10 Sketch diagram of disc TR6 6.11 Sketch diagram of disc TR7 6.12 Sketch diagram of disc TR8 6.13 Erratic separation of liquid from TR7 6.14-6.33 Spark photographs showing the ligament of liquid formed from disc TR8 over a range of operating conditions 6.14 0.37 ml/min 6000 rpm 6
Science of The Total Environment, 1994
The aerodynamic characteristics of 'model' tree canopies within a wind tunnel are reported. Wind ... more The aerodynamic characteristics of 'model' tree canopies within a wind tunnel are reported. Wind speed profiles above and within canopies comprising Norway spruce (Picea abies) and Holm oak (Quercus ilex) saplings were determined by hot wire and hot film anemometry at a free-stream air velocity subsequently used for experiments on the dry deposition of aerosol particles to both canopies. Friction velocities (U*) of 128 and 104 cm s-1 were observed for Norway spruce and Holm oak, respectively. Vertical distributions of wind speed (U) and turbulence intensity (i) within the canopies were similar in form and magnitude to those reported in the literature for full-sized forest canopies, suggesting that the sapling canopies provide a realistic 'model' with which to investigate the process of dry deposition.
Science of The Total Environment, 1994
A wind tunnel experiment is reported in which the dry deposition of a 1-/xm MMAD monodisperse sil... more A wind tunnel experiment is reported in which the dry deposition of a 1-/xm MMAD monodisperse silica aerosol to Norway spruce (Picea abies) was investigated. Model canopies were constructed from individual 2-to 3-year-old saplings so as to allow the full development of a turbulent boundary layer within the wind tunnel above the canopy. Deposition velocities (Vg) and interception fractions (/) are presented for both total canopy and for 14 sub-components of the canopy in four horizontal layers. Total canopy Vg was approximately seven times greater than that of a grass sward in the same wind tunnel. The total canopy/g value was also higher than that of grass, with a value for spruce of 98%. Both Vg and /" values were attenuated in an approximately exponential fashion with vertical penetration downwards into the canopy. A series of two-way analyses of variance revealed significant differences in deposition between needle and stem tissues, and also between vertically and horizontally distinct canopy components. Furthermore, significant interactions between deposition to needle and stem tissues at different heights within the canopy indicated a complex pattern of deposition. It is suggested that the initial capture of the bulk of aerosol deposits on the upper and outer surfaces of individual spruce trees provides the potential for a substantial prompt redistribution of the deposit by resuspension due to wind action.
Journal of Environmental Monitoring, 2004
An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the siz... more An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51 980 particles, in the size range 0.3-7.4 mm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d v 2.5 mm) and coarse (d w 2.5 mm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium.
Journal of Aerosol Science, 2000
Journal of Aerosol Science, 1997
Journal of Aerosol Science, 1995
Environmental Pollution, 1996
There is a requirement for data describing the loss with time of particulate contamination from p... more There is a requirement for data describing the loss with time of particulate contamination from plant canopies. Measurements were made of the loss rates of monodispersed silica spheres (three sizes, with Mass Median Aerodynamic Diameters (MMADs) 1.9, 5.3 and 8.4 microm) from wheat (Triticum aestivum) and broad bean (Vicia faba) canopies. The spheres were labelled with tracers detectable by Instrumental Neutron Activation Analysis (INAA). Canopies were contaminated under realistic turbulence conditions in a wind tunnel, then removed to sheltered and exposed field sites or to a glasshouse containing a rain simulator. Samples were taken periodically, and the level of contamination per plant determined by INAA. Statistical analysis of the resulting data suggested an offset exponential loss model, with a residue of deposit that is not lost over time. Loss half-lives in the order of 1-2 days were obtained for an exposed wheat crop and 3-4 days for a partially sheltered wheat crop, with permanent residues of initial deposit for the exposed crop of 4-8%, and for the partially sheltered crop of 22-52%. A broad bean crop under glasshouse conditions showed loss half-lives of 0.5-1.5 days with residues of 22-26% initial contamination. A double exponential loss model also fitted the data well in some cases, and it is possible that a slow loss of the residual deposit occurs, being masked by noise in the current data set.
Environment International, 2006
With both climate change and air quality on political and social agendas from local to global sca... more With both climate change and air quality on political and social agendas from local to global scale, the links between these hitherto separate fields are becoming more apparent. Black carbon, largely from combustion processes, scatters and absorbs incoming solar radiation, contributes to poor air quality and induces respiratory and cardiovascular problems. Uncertainties in the amount, location, size and shape of atmospheric black carbon cause large uncertainty in both climate change estimates and toxicology studies alike. Increased research has led to new effects and areas of uncertainty being uncovered. Here we draw together recent results and explore the increasing opportunities for synergistic research that will lead to improved confidence in the impact of black carbon on climate change, air quality and human health. Topics of mutual interest include better information on spatial distribution, size, mixing state and measuring and monitoring.
Atmospheric Environment, 2001
A dynamic multi-compartment computer model has been developed to describe the physical processes ... more A dynamic multi-compartment computer model has been developed to describe the physical processes determining indoor pollutant concentrations as a function of outdoor concentrations, indoor emission rates and building characteristics. The model has been parameterised for typical UK homes and workplaces and linked to a time-activity model to calculate exposures for a representative homemaker, schoolchild and o$ce worker, with respect to NO. The estimates of population exposures, for selected urban and rural sites, are expressed in terms of annual means and frequency of hours in which air quality standards are exceeded. The annual mean exposures are estimated to fall within the range of 5}21 ppb for homes with no source, and 21}27 ppb for homes with gas cooking, varying across sites and population groups. The contribution of outdoor exposure to annual mean NO exposure varied from 5 to 24%, that of indoor penetration of outdoor air from 17 to 86% and that of gas cooking from 0 to 78%. The frequency of exposure to 1 h mean concentrations above 150 ppb was very low, except for people cooking with gas.
Atmospheric Environment, 2004
An understanding of the likely pattern of dry deposition of small particles over a landscape is a... more An understanding of the likely pattern of dry deposition of small particles over a landscape is a key prerequisite to designing strategies for sampling ground contamination following routine or accidental releases to atmosphere. Wind tunnel and computational fluid dynamics studies of flow and particle deposition over landscape features have been carried out. The presence of elevated landscape features showed a strong effect on the pattern of deposition relative to a flat landscape case. A relatively small area of increased deposition occurred on the upwind face, with a larger area of decreased deposition in the wake. The slope of the landscapes affected the magnitude of the effect and the size of the affected region in the wake. The pattern of deposition for a three-dimensional landscape was complex. Good quantitative agreement was seen between the CFD predicted deposition and the wind tunnel results for the twodimensional cases and reasonable qualitative agreement for the three-dimensional case, suggesting that CFD studies might be an appropriate tool to systematically explore the influence of complex topography on particle deposition.
Atmospheric Environment, 1997
ABSTRACT
Atmospheric Environment, 2006
ABSTRACT A probabilistic model (INDAIR) has been developed to predict air pollutant concentration... more ABSTRACT A probabilistic model (INDAIR) has been developed to predict air pollutant concentrations in home microenvironments in the UK. The model has been parameterised using probability functions for four pollutants simultaneously (NO2, CO, PM10 and PM2.5), under three emission scenarios (no source, cooking, smoking). Model predictions are broadly consistent with data on indoor concentrations in UK homes. Modelled mean concentrations were most sensitive to variation in outdoor concentrations, air exchange rate and deposition velocity in no-source scenarios, while modelled peak concentrations in source rooms were most sensitive to variation in emission rate and room size. Under model assumptions, smoking and cooking made a significant contribution to annual mean indoor concentrations of PM10 and PM2.5, gas cooking made a significant contribution to annual mean indoor NO2 concentrations, while annual mean CO concentrations were dominated by infiltration of outdoor air. The modelled frequency distributions of 24 h mean values showed 95 percentile concentrations that were typically twice the mean concentrations in no-source scenarios, and 3–4 times the mean concentration during emission peaks. The higher exposure of residents in homes at the upper ends of the frequency distributions may be associated with adverse health outcomes, and probabilistic modelling approaches can contribute to identification of the characteristics of homes with high indoor concentrations.
American Journal of Respiratory and Critical Care Medicine, 2000
This project brought together NCAS (National Centre for Atmospheric Science) scientists to study ... more This project brought together NCAS (National Centre for Atmospheric Science) scientists to study atmospheric chemical processes, and particularly those affecting atmospheric aerosol, in London by using the following sampling platforms:• the BT tower at an elevation of 170 metres above ground level.• adjacent Regents Park where ground level measurements were made.• Marylebone Road at roadside in the street canyon. Two air sampling campaigns were carried out throughout the months of October 2006 and October/ ...
Radioprotection, 2002
Given the potential radiological significance of the transfer of radionuclides to fruit, a Fruits... more Given the potential radiological significance of the transfer of radionuclides to fruit, a Fruits Working Group was set up in 1997 within the framework of the Programme on Biosphere Modelling and Assessment (BIOMASS), promoted by the International Atomic Energy Agency (IAEA) and in cooperation with the International Union of Radioecology (IUR). The aim of this working group was to improve understanding of the processes affecting the migration of radionuclides in fruit systems and to identify uncertainties associated with modelling the transfer of radionuclides to fruit. The main activities of the Fruits Working Group included: (i) a review of experimental, field and modelling information on the transfer of radionuclides to fruit; (ii) a derivation of a fruit conceptual model; (iii) a database of model parameters; (iv) a collection of additional information from experimental studies; (v) model intercomparison studies; and (vi) a validation study. This paper presents an overview of the main activities and results.
Aerial application of insecticides is likely to remain an important component in realistically-co... more Aerial application of insecticides is likely to remain an important component in realistically-costed vector and migratory pest control operations for the foreseeable future. The objective of this work was to identify or design improved atomisers for use in two such operations, tsetse (Glossina sp.) and African armyworm (Spodoptera exempta) control, the former requiring an insecticide aerosol ýx'ith a VMD of 20 to 30ýim at rates upto 0.5 litres/minute and the latter a fine spray with a VMD of 80 to 120ýtm at rates around 16 litres/minute. In both cases rotary atomisation was confirmed as the most appropriate technique. Assessments were made of seven commerciall%, available atomisers and two existinc, prototypes, on the basis of existing reports and new data generated under simulated flight conditions in a wind tunnel. Droplet sizing was carried out using an optical array probe set to give a resolution of 54m over a range of 3.6-3) 12.54m. None of the atomisers tested met the specification for tsetse-spraying, the limiting factors being rotation speed and inability to distribute low volumes of liquid across their full atomising surface. The Micronair AU4000 and AU5000 and the Micron X-I were found to be suitable for armyworm control, the Micron X-1 having the additional ability to produce spray with VMDs down to 40ýim. A review of rotary atomiser literature provided design guidelines for the design of an atomiser capable of meeting tsetse specifications. The principle effect of liquid flow 4D within the atomiser was found to be on the uniformity of fluid distribution. Premature ligament formation and formation of cross-flow vortices were identified 415-ligament occured at a Weber number of between 4 and 5, similar to reported values for liquid jets in a cross flo%v of cyas. Droplet sizing indicated that the specified performance for tsetse operations could be obtained from 50mm diameter atomisers with a total of around _'30000 issuing points at a rotation speed of 26000 RPNI. This Zý sucy(yested cN, lindcr rather than disc-based atomisers. A slit was found to be impractical as a means of distributing liquid unifom-ily at high rotation speeds but distribution was sucý: essfully achieved using a porous flow resistor. Prototype wind-and electi-ically-driven atornisers were constructed using In particular I am indebted to the following: My supervisor, Steve Parkin, for his guidance, for "giving me my head", and for his reassuring knack of putting things in perspective whenever I felt panic setting in. Professor John Spillman, originally my co-supervisor, for his enthusiastic interest in the project long after his official involvement ceased, and for staying on the right side Oust) of the thin line between mentor and tormentor when it came to the Hard Sums. The incomparable John Wyatt. Optical, mechanical or electronic, he could always make things work and always found the time to do so. Derek Giles, for teaching me how things are made and for turning my naively optimistic drawings into finely crafted reality. Also Paul, Malcolm, Barry, Wayne and Trevor, for their help and their good-humoured tolerence. The gentlemen of the Natural Resources Institute-Cliff Lee, Reg Allsopp, Don Johnstone, Jerry Cooper, Hans Dobson, Francesca Casci and Rob Fenn, for advice, invaluable discussions and words of encouragement. Also for some jolly evenings in Harare and for showing me how to hunt scorpions. The staff of ICAP, particularly Ian Outrarn for many hours of entertainment, and my friend and colleague Neil Morgan, who taught me humility on the electronic golf course. My current employers, for their support whilst writing this thesis, and especially Margaret Minski for preferring the carrot to the stick. The other people, too numerous to mention, whose brains I have picked over the years. My venerable parents. Bemused they may have been by it all but not once did they tell me it was "time I got myself a proper job. Above all I am grateful to Joanne for her love and support over the last few years. subscripts: air liquid radial List of Figures 2.1 Schematic diagram of the optical system of the PMS OAP-26OX 2.2 Schematic diagram of the optical system of the PMS FSSP-100 4.1 Schematic plan view of the Cranfield aerial atomiser test facility 4.2 The Unirot-4 atomiser 4.3 The Beecomist 360A atorniser 4.4a The feed system of the Beecomist 360A emitting water at low flowrate 4.4b The feed system of the Beecomist 360A emitting water at high flowrate 4.5a The feed system of the Micron X-15 emitting Glossinex at 0.2 litres/minute 4.5b The modified Micron X-15 feed system emitting Glossinex at 0.2 litres/minute 4.6 The Micronair AU4000 atomiser 4.7 The Micronair AU5000 atomiser 4.8 The Micron X-1 atomiser 5.1 Stages in atornisation from a rotary atomiser 6.1a Components of the disc observation system 6.1b Circuit diagram of the strobe/spark trigger 6.2 The spark photography system 6.3 Spiral vortices forming in liquid flowing over a 100mm diameter rotating disc 6.4 Trial ligament generators of type TR 1 6.5 Trial ligament generator TR3 6.6 Erratic separation of liquid ligaments from TR3 6.7 Trial ligament generator TR4 6.8 Trial ligament generator TR5 6.9 Liquid escaping from the groove in TR5 6.10 Sketch diagram of disc TR6 6.11 Sketch diagram of disc TR7 6.12 Sketch diagram of disc TR8 6.13 Erratic separation of liquid from TR7 6.14-6.33 Spark photographs showing the ligament of liquid formed from disc TR8 over a range of operating conditions 6.14 0.37 ml/min 6000 rpm 6
Science of The Total Environment, 1994
The aerodynamic characteristics of 'model' tree canopies within a wind tunnel are reported. Wind ... more The aerodynamic characteristics of 'model' tree canopies within a wind tunnel are reported. Wind speed profiles above and within canopies comprising Norway spruce (Picea abies) and Holm oak (Quercus ilex) saplings were determined by hot wire and hot film anemometry at a free-stream air velocity subsequently used for experiments on the dry deposition of aerosol particles to both canopies. Friction velocities (U*) of 128 and 104 cm s-1 were observed for Norway spruce and Holm oak, respectively. Vertical distributions of wind speed (U) and turbulence intensity (i) within the canopies were similar in form and magnitude to those reported in the literature for full-sized forest canopies, suggesting that the sapling canopies provide a realistic 'model' with which to investigate the process of dry deposition.
Science of The Total Environment, 1994
A wind tunnel experiment is reported in which the dry deposition of a 1-/xm MMAD monodisperse sil... more A wind tunnel experiment is reported in which the dry deposition of a 1-/xm MMAD monodisperse silica aerosol to Norway spruce (Picea abies) was investigated. Model canopies were constructed from individual 2-to 3-year-old saplings so as to allow the full development of a turbulent boundary layer within the wind tunnel above the canopy. Deposition velocities (Vg) and interception fractions (/) are presented for both total canopy and for 14 sub-components of the canopy in four horizontal layers. Total canopy Vg was approximately seven times greater than that of a grass sward in the same wind tunnel. The total canopy/g value was also higher than that of grass, with a value for spruce of 98%. Both Vg and /" values were attenuated in an approximately exponential fashion with vertical penetration downwards into the canopy. A series of two-way analyses of variance revealed significant differences in deposition between needle and stem tissues, and also between vertically and horizontally distinct canopy components. Furthermore, significant interactions between deposition to needle and stem tissues at different heights within the canopy indicated a complex pattern of deposition. It is suggested that the initial capture of the bulk of aerosol deposits on the upper and outer surfaces of individual spruce trees provides the potential for a substantial prompt redistribution of the deposit by resuspension due to wind action.
Journal of Environmental Monitoring, 2004
An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the siz... more An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51 980 particles, in the size range 0.3-7.4 mm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d v 2.5 mm) and coarse (d w 2.5 mm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium.
Journal of Aerosol Science, 2000
Journal of Aerosol Science, 1997
Journal of Aerosol Science, 1995
Environmental Pollution, 1996
There is a requirement for data describing the loss with time of particulate contamination from p... more There is a requirement for data describing the loss with time of particulate contamination from plant canopies. Measurements were made of the loss rates of monodispersed silica spheres (three sizes, with Mass Median Aerodynamic Diameters (MMADs) 1.9, 5.3 and 8.4 microm) from wheat (Triticum aestivum) and broad bean (Vicia faba) canopies. The spheres were labelled with tracers detectable by Instrumental Neutron Activation Analysis (INAA). Canopies were contaminated under realistic turbulence conditions in a wind tunnel, then removed to sheltered and exposed field sites or to a glasshouse containing a rain simulator. Samples were taken periodically, and the level of contamination per plant determined by INAA. Statistical analysis of the resulting data suggested an offset exponential loss model, with a residue of deposit that is not lost over time. Loss half-lives in the order of 1-2 days were obtained for an exposed wheat crop and 3-4 days for a partially sheltered wheat crop, with permanent residues of initial deposit for the exposed crop of 4-8%, and for the partially sheltered crop of 22-52%. A broad bean crop under glasshouse conditions showed loss half-lives of 0.5-1.5 days with residues of 22-26% initial contamination. A double exponential loss model also fitted the data well in some cases, and it is possible that a slow loss of the residual deposit occurs, being masked by noise in the current data set.
Environment International, 2006
With both climate change and air quality on political and social agendas from local to global sca... more With both climate change and air quality on political and social agendas from local to global scale, the links between these hitherto separate fields are becoming more apparent. Black carbon, largely from combustion processes, scatters and absorbs incoming solar radiation, contributes to poor air quality and induces respiratory and cardiovascular problems. Uncertainties in the amount, location, size and shape of atmospheric black carbon cause large uncertainty in both climate change estimates and toxicology studies alike. Increased research has led to new effects and areas of uncertainty being uncovered. Here we draw together recent results and explore the increasing opportunities for synergistic research that will lead to improved confidence in the impact of black carbon on climate change, air quality and human health. Topics of mutual interest include better information on spatial distribution, size, mixing state and measuring and monitoring.
Atmospheric Environment, 2001
A dynamic multi-compartment computer model has been developed to describe the physical processes ... more A dynamic multi-compartment computer model has been developed to describe the physical processes determining indoor pollutant concentrations as a function of outdoor concentrations, indoor emission rates and building characteristics. The model has been parameterised for typical UK homes and workplaces and linked to a time-activity model to calculate exposures for a representative homemaker, schoolchild and o$ce worker, with respect to NO. The estimates of population exposures, for selected urban and rural sites, are expressed in terms of annual means and frequency of hours in which air quality standards are exceeded. The annual mean exposures are estimated to fall within the range of 5}21 ppb for homes with no source, and 21}27 ppb for homes with gas cooking, varying across sites and population groups. The contribution of outdoor exposure to annual mean NO exposure varied from 5 to 24%, that of indoor penetration of outdoor air from 17 to 86% and that of gas cooking from 0 to 78%. The frequency of exposure to 1 h mean concentrations above 150 ppb was very low, except for people cooking with gas.
Atmospheric Environment, 2004
An understanding of the likely pattern of dry deposition of small particles over a landscape is a... more An understanding of the likely pattern of dry deposition of small particles over a landscape is a key prerequisite to designing strategies for sampling ground contamination following routine or accidental releases to atmosphere. Wind tunnel and computational fluid dynamics studies of flow and particle deposition over landscape features have been carried out. The presence of elevated landscape features showed a strong effect on the pattern of deposition relative to a flat landscape case. A relatively small area of increased deposition occurred on the upwind face, with a larger area of decreased deposition in the wake. The slope of the landscapes affected the magnitude of the effect and the size of the affected region in the wake. The pattern of deposition for a three-dimensional landscape was complex. Good quantitative agreement was seen between the CFD predicted deposition and the wind tunnel results for the twodimensional cases and reasonable qualitative agreement for the three-dimensional case, suggesting that CFD studies might be an appropriate tool to systematically explore the influence of complex topography on particle deposition.
Atmospheric Environment, 1997
ABSTRACT
Atmospheric Environment, 2006
ABSTRACT A probabilistic model (INDAIR) has been developed to predict air pollutant concentration... more ABSTRACT A probabilistic model (INDAIR) has been developed to predict air pollutant concentrations in home microenvironments in the UK. The model has been parameterised using probability functions for four pollutants simultaneously (NO2, CO, PM10 and PM2.5), under three emission scenarios (no source, cooking, smoking). Model predictions are broadly consistent with data on indoor concentrations in UK homes. Modelled mean concentrations were most sensitive to variation in outdoor concentrations, air exchange rate and deposition velocity in no-source scenarios, while modelled peak concentrations in source rooms were most sensitive to variation in emission rate and room size. Under model assumptions, smoking and cooking made a significant contribution to annual mean indoor concentrations of PM10 and PM2.5, gas cooking made a significant contribution to annual mean indoor NO2 concentrations, while annual mean CO concentrations were dominated by infiltration of outdoor air. The modelled frequency distributions of 24 h mean values showed 95 percentile concentrations that were typically twice the mean concentrations in no-source scenarios, and 3–4 times the mean concentration during emission peaks. The higher exposure of residents in homes at the upper ends of the frequency distributions may be associated with adverse health outcomes, and probabilistic modelling approaches can contribute to identification of the characteristics of homes with high indoor concentrations.
American Journal of Respiratory and Critical Care Medicine, 2000
This project brought together NCAS (National Centre for Atmospheric Science) scientists to study ... more This project brought together NCAS (National Centre for Atmospheric Science) scientists to study atmospheric chemical processes, and particularly those affecting atmospheric aerosol, in London by using the following sampling platforms:• the BT tower at an elevation of 170 metres above ground level.• adjacent Regents Park where ground level measurements were made.• Marylebone Road at roadside in the street canyon. Two air sampling campaigns were carried out throughout the months of October 2006 and October/ ...
Radioprotection, 2002
Given the potential radiological significance of the transfer of radionuclides to fruit, a Fruits... more Given the potential radiological significance of the transfer of radionuclides to fruit, a Fruits Working Group was set up in 1997 within the framework of the Programme on Biosphere Modelling and Assessment (BIOMASS), promoted by the International Atomic Energy Agency (IAEA) and in cooperation with the International Union of Radioecology (IUR). The aim of this working group was to improve understanding of the processes affecting the migration of radionuclides in fruit systems and to identify uncertainties associated with modelling the transfer of radionuclides to fruit. The main activities of the Fruits Working Group included: (i) a review of experimental, field and modelling information on the transfer of radionuclides to fruit; (ii) a derivation of a fruit conceptual model; (iii) a database of model parameters; (iv) a collection of additional information from experimental studies; (v) model intercomparison studies; and (vi) a validation study. This paper presents an overview of the main activities and results.