The Meteorology and Climatology of Air Pollution in West Central Scotland
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THE METEOROLOGY AND CLIMATOLOGY OF AIR POLLUTION IN WEST CENTRAL SCOTLAND A Thesis presented for the Degree of Doctor of Philosophy of the University of Glasgow by JOHN C. ýWEENEY Department of Geography, University of Glasgow, Glasgow. 1980 TO MY PARENTS -1- PREFACE In recent decades the, age old problem of air pollution has assumed a new importance as evidence has become available concerning its adverse effects both on a local and global scale. Awareness of these effects has been most marked in densely populated industrialised countries where the juxtaposition of people and their employment makes 'living with air pollutiona necessaryi though unwelcome reality. In most of these areas some form of written or unwritten guidelines have evolved which express a consensus com- promise between the adverse effects of air pollution on the one hand and the material prosperity accompanying industrial- isation on the other. Increasingly, internationally es- tablished criteria are being utilised as a basis for managing air quality within a region, and for assessing the impact of planned new sources within it. Such an approach implies that the effect of a new or existing source is readily quantifiable in terms of its impact on ground level concentrations. This is not the case and was demonstrated by previous workers with reference to the changing industrial landscape of West Central Scotland. Environmental impact analyses in relation to proposed new high level sources in the Clyde Estuary were seen to be in- conclusive. This was attributed to a gap in knowledge con- cerning the interaction of topographical and meteorological influences on pollution dispersal within the region. The following study is essentially a response to the need acknowledged above. It seeks to investigate in detail various meteorological and climatological factors which, acting within the topographical make up of West Central Scotland, encourage or restrict the dispersal of emissions from existing or planned pollutant sources. Such an under- standing, though developed for a unique location, will in- evitably have a contribution to make in relation to similar problems in other areas. Basically then two objectives can be noted, one academic, -2- the other applied. The first aim is to examine the role of atmospheric factors in enhancing ground level concentrations of smoke and sulphur dioxide in the region, and the second is to illustrate the utility of such data in air quality management schemes. -3- ACKNOWLEDGMENTS I would like to express my gratitude to several workers who, acting individually or on behalf of various organisations, have rendered invaluable assistance in the preparation of this thesis. On an academic level a primary obligation must be re- cognised to Emeritus Professor Ronald Miller and Professor Ian B. Thompson for permitting me to pursue post graduate research in the Department of Geography, University of Glasgow from 1975 to 1978. For the period since then thanks are also extended to Professor William J. Smyth for permitting completion of the work at St. Patrick's College, Maynooth. Establishing and maintaining the thermohygrograph net- work involved co-operation from several bodies to whom I would like to e.-ýpress my thanks. These include officials of the Planning Department Renfrew District Council, the Water Department of Strathclyde Regional Council, and the Senior Meteorological Officer, Glasgow Airport. Thanks are also due to Captain P. R. Byrd, Commanding Officer, U. S. Naval Communication Station, Londonderry for security concessions granted in respect of the Gleniffer thermohygrograph installation. Data was made available by officials of the Environmental Health Departments of Glasgow, Paisley and Inverclyde Districts and by Mr. Harry McKellar of Glasgow Weather Centre, just prior to his recent retirement. Assistance in computer programming must also be acknowledged from Mr. Graham Reid of the Planning Department Strathclyde Regional Council, who was also re- sponsible for devising several of the programmes utilised in the earlier part of the study. Permission to reproduce Plate 2 must also be acknowledged from the Rev. James McGreehin. -4- Mention must also be made of the invaluable assistance' of two members of the Geography Department: ýMaria Cunningham and Cathie Gunn. As is quite cleartheir secretarial and cartographical skills are of the highest calibre, but also their patience and endurance in what must have seemed an endless profusion of graphs and Greek letters was most encouraging. Finally I am indebted to my supervisor, Cyril Halstead, Senior Lecturer in Geography, University of Glasgow, without whose constant encouragement this study would never have come to fruition. His extensive expertise in the fields of climatology and meteorology is matched only by his incisive and imaginative approach to academic research. Studying under him has been both a privilege and an intensely enriching experience. -5- TABLE OF CONTENTS Page Preface 1 Acknowledgemenýs Table of Contents 5 Abstract List of Figures 10 List of Tables and Plates 12 Chapter 1. Introduction 14 1.1 Man's Impact on the Atmosphere 14 1.2 The Background to the Air Pollution 15 Project 1.3 The Study Area - West Central Scotland 20 Chapter 2. The Background to the Air Pollution Problem 26 2.1 Nature and occurrence 26 2.2 Smoke and Smoke Control 32 2.3 Sulphur Dioxide 44 2.4 The Adverse Effects of Air Pollution 49 2.5 Control Policies 55 Chapter 3. Conditions in West Central Scotland 66 3.1 Emissions of Smoke and Sulphur Dioxide 66 3.2 Emissions and Concentration Potential 71 3.3 Fluctuations in Emissions 73 3.4 Ground Level Concentrations of Smoke and Sulphur Dioxide 78 3.5 Smoke and Sulphur Dioxide Concentration Trends 87 Chapter 4. The Data and its Limitations 97 4.1 Atmospheric Pollution Data 97 4.2 Meteorological Data 103 4.3 Other Sources of Data 106 4.4 Computer Handling of Data 109 Chapter 5. Pollution Concentrations - Temporal Cycles and Prequency Distribution 116 5.1 Seasonal Fluctuations 116 5.2 Weekly Pollution Cycles 121 5.3 The Frequency Distribution of Pollution Data 124 Chapter 6. The Estimation of Atmospheric Stability from Surface Observations 129 6.1 Estimation Theory and Techniques 129 6.2 The Abbotsinch Stability Regime 133 - Page Chapter 7. Wind Relationships 142 7.1 The Abbotsinch Wind Regime 142 7.2 Wind Direction 148 7.3 Wind Velocity 159 Chapter 8. Inversions of Temperature ( 1) 165 8.1 The Nature and Influence of Temperature Inversions 165 8.2 Surface Inversions 167 8.3' Surface Inversions : their Role in Air Pollution Studies 171 8.4 Surface Inversions in a Urban Dimension 176 Chapter 9. Inversions of Temperature (11) 178 9.1 High Level Trapping and the Tall Stack Controversy 178 9.2 Free Air Inversions 184 9.3 Subsidence Inversions and Air Pollution 186 189 9.4 Calculation of the Mixing Height Chapter 10.. Critical Inversion Heights 192 10.1 Effective Limitations on Mixing Height 192 10.2 The Interaction between Inversion Height and Relief 194 10.3 The Effect of Thermal and Turbulent Mix- ing 200 Chapter 11. Inversions and Easterly__Winds 205 11.1 The Basis of Enhanced Pollution with 205 Easterly Winds 11.2 Potdntial Major Source Of S02 in the Forth Valley 207 11.3 Measuring the Effect of the Forth Estuary Sources 211 Chapter 12. Inversion Persistency 225 12.1 Air Pollution Potential 225 12.2 Previous Work in Inversion Persistence 227 12.3 Long Kesh Inversion Persistence 231 Chapter 13. Periods of Enhanced Concentrations : Causes and Tn-c: t- Stlldips-- 24b 13.1 Air Pollution as an Environmental Hazard 246 13.2 Fog 249 13.3 Pollution Episodes Associated with Fog 256 Chapter 14. Enhanced Sulphur Dioxide Concentrations in 269 Summer 1 14.1 Less Marked Meteorological Influences 269 14.2 A Case Study in June/July 1975 272 14.3 Long Distance Transport of Sulphur Dioxide280 -7- Page Chapter 15. Inverkip Power Station :a Case Study 283 15.1 The Background 283 15.2 Loss of Visual Amenity 287 15.3 Air Pollution Effects : Nonhebel's Report 291 15A A Critique of Nonhebel's Report 295 15.5 A Postscript on Concentrations at Linwood under Westerly Winds 304 Chapter 16. Conclusions 308 Appendix A 319 Bibliography 322 Addendum 333 -8- ABSTRACT Despite considerable amelioration in ground levelconcen- trations of smoke and sulphur dioxide in West Central Scotland in the last two decades, high pollution episodes still occur high on occasion, and winter averages of So 2 still characterise parts of the conurbation. For these reasons a continuing monitoring programme remains essential, largely as a means of projecting and assessing the impact of new high level sources on both týe Clyde and Forth Estuaries. In relation to these, however, classical dispersion models and formulae have not been found to be as effective as anticipated, largely because of their failure to accommodate the interaction of the relief characteristics of the area with several aspects of its meteorological environment, most notably inversions of temperature in the lower atmospheric levels. Evidence from fieldwork and from extensive analysis of radiosonde data suggests that such inversions are fairly frequent occurrences in the Glasgow Basin and can often prove persistent, lasting several days in some cases. In such circumstances effluent emitted within the Basin may be trapped, giving rise to enhanced ground level concentrations, and in extreme cases to the pollution episodes characteristic of the area in the past. Detailed examination of these features enabled conclusions concerning their likely occurrence, duration, altitude and behaviour to be drawn. In a wider perspective the inversion climatology of West Central Scotland was compared with other areas and was found to reflect large scale synoptic controls. On a more practical level however it was envisaged incorporating such inversion data into future dispersal modelling cdlculations. of more immediat& significance as far as West Central Scotland was concerned was the discovery that the effectiveness of these pollution lids varied considerably with altitude, being most effective at particular height categories below 1500 metres.