OCS Study 

MMS 2000-014 

Coastal Marine Institute 

Air Quality and Dispersion Meteorology 

over the Northeastern Gulf of Mexico: 

Measurements, Analyses, and Syntheses 

U .S . Department of the Interior Cooperative,Agreement Minerals 7Vlanagement Service A Coastal Marine Institute 

Gulf of Mexico OCS Region 

~ W, ~ 

Louisiana State University 
OCS Study 

MMS 2000-014 

Coastal Marine Institute 

Air Quality and Dispersion Meteorology 

over the Northeastern Gulf of Mexico: 

Measurements, Analyses, and Syntheses 

Authors 

S. A. Hsu 

and 

B . W. Blanchard 

March 2000 

Prepared under MMS Contract 

14-35-0001-30660-19925 

by 

Coastal Marine Institute 

Louisiana State University 

Baton Rouge, Louisiana 70803 

Published by 

U .S. Department of the Interior Cooperative Agreement 

Minerals Management Service Coastal Marine Institute 

Gulf of Mexico OCS Region Louisiana State University 

DISCLAIMER 

This report was prepared under contract between the Minerals Management Service (MMS) and the 

Coastal Studies Institute, Louisiana State University . This report has been technically reviewed by 

the MMS and approved for publication. Approval does not signify that the contents necessarily 

reflect the views and policies of the Service, nor does mention of trade names or commercial 

products constitute endorsement or recommendation for use. It is, however, exempt from review 

and compliance with MMS editorial standards. 

REPORT AVAILABILITY 

Extra copies of the report may be obtained from the Public Information Office (Mail Stop 5034) at 

the following address: 

U.S . Department of the Interior 

Minerals Management Service 

Gulf of Mexico OCS Region 

Attention : Public Information Office (MS 5034) 

1201 Elmwood Park Boulevard 

New Orleans, Louisiana 70123-2394 

Telephone Number: 1-800-200-GULF or 

504-736-2519 

CITATION 

Suggested citation : 

Hsu, S. A. and B. W. Blanchard. 2000. Air Quality and Dispersion Meteorology Over the 

Northeast Gulf of Mexico : Measurements, Analyses, and Syntheses. OCS Study MMS 

2000-014. U.S . Dept. of the Interior, Minerals Management Service, Gulf of Mexico OCS 

Region, New Orleans, LA. 188 pp. 

FRONT COVER 

Advanced Very High Resolution satellite infrared image of our study area in the northeast Gulf of 

Mexico captured on 3 March 1997 0859 GMT (courtesy of the Earth Scan Lab, Louisiana State 

University) . 

iii 

ABSTRACT 

Meteorological and air quality data recorded during the period of May 1997 through July 1998 is 

reduced and presented in this final report . The data was acquired from monitoring stations located 

on Dauphin and Breton Islands in the northeast Gulf of Mexico . It was found that the hourly 

average pollutant (SOz and NOZ) concentrations at both sites were less than 6 ppb during over half 

of this reporting period . Weak seasonal and diurnal trends were exhibited at Dauphin Island ; the 

seasonal trend was less evident at Breton Island and diurnal peaks were generally not 

distinguishable. Maximum concentrations of both SOz and NOZ at Dauphin Island were primarily 

associated with wind flow from the north and northeast; maximum SOZ concentrations at Breton 

were also seen with northerly winds, but NOZ maximums were often recorded under flow from the 

south and southwest. Unstable atmospheric conditions dominated over the Breton Sound area 

throughout the year, with free convection being observed as often as 15% of the time. Methods for 

determining the stability category, turbulence intensity, drag coefficient, and mixed heights from 

routinely available measurements are described . Computed values are in good agreement with 

observed data. Both air quality and meteorological results are consistent with findings from datasets 

previously obtained in this area. 

v 

TABLE OF CONTENTS 

List of Figures ix 

List of Tables xvii 

Acknowledgments xix 

I. Introduction 1 

II . Data Acquisition and Processing 3 

A. Overview 3 

B. Dauphin Island 3 

C. Breton Island 14 

III . Analysis and Results 27 

A. Dauphin Island Air Quality 27 

B. Breton Island Air Quality 75 

C. Station Comparison 136 

D. Boundary Layer and Dispersion Meteorology Over Breton Island and Sound 151 

1 . Description of Key Processes in Pollutant Transport and Dispersion Over 151 

the Breton National Wildlife Area 

a. Topography 151 

b. Air-Sea Exchange 151 

c . Wind-Wave Interaction 153 

d . Atmospheric Turbulence 155 

e. Vertical Mixing 157 

1 . The Vertical Eddy Diffusivity 157 

2 . The Mixing Height 157 

2 . Use of Observations to Compare Methods that Evaluate Parameters 159 

Associated with Key Processes 

a. Determining Z/L 159 

b. Turbulence Intensity 161 

c . The Mixing Height 169 

IV. Summary 184 

V. References 186 

vii 

LIST OF FIGURES 

Figure Page 

1 Advanced Very High Resolution Radiometer (AVHRR) satellite thermal image 2 

showing the approximate locations of our two air quality monitoring stations 

(courtesy of Buddy Martin, Earth Scan Lab, Louisiana State University) . 

2 Layout of air quality monitoring station at Dauphin Island (distances are 4 

approximated) . 

3 Schematic of the Kerr-McGee facility on Breton Island showing location of 15 

monitoring site following Hurricane Danny. 

4 May 1997 time series of Dauphin Island hourly-averaged concentrations and 28 

wind direction from DPIA 1 . SOZ missing on 15 May. 

5 June 1997 time series of Dauphin Island hourly-averaged concentrations and 29 

wind direction from DPIA 1 . 

6 July 1997 time series of Dauphin Island hourly-averaged concentrations and 30 

wind direction from DPIA 1 . Air quality data missing on 4 July and in midmonth as depicted . 

7 August 1997 time series of Dauphin Island hourly-averaged concentrations and 31 

wind direction from DPIA1. SOz data missing on 18 August. 

8 September 1997 time series of Dauphin Island hourly-averaged concentrations 32 

and wind direction from DPIA1. 

9 October 1997 time series of Dauphin Island hourly-averaged concentrations and 33 

wind direction from DPIA 1 . 

10 November 1997 time series of Dauphin Island hourly-averaged concentrations 34 

and wind direction from DPIA1. NO,, missing on 24 November. 

11 December 1997 time series of Dauphin Island hourly-averaged concentrations 35 

and wind direction from DPIA1 . Missing SOZ data on 29 December. 

12 January 1998 time series of Dauphin Island hourly-averaged concentrations and 36 

wind direction from DPIA1 . SOz data missing on 5 and 21 January, NO,, 

missing on 7 and 21 January. 

13 February 1998 time series of Dauphin Island hourly-averaged concentrations 37 

and wind direction from DPIA 1 . NO,, missing on 3 and 16 February, SOZ on 16 

and 17 February. 

14 March 1998 time series of Dauphin Island hourly-averaged concentrations and 38 

wind direction from DPIA1. SOZ and NO,, missing on 20 March. 

15 April 1998 time series of Dauphin Island hourly-averaged concentrations and 39 

wind direction from DPIA1. SOz data missing on 13-14 April . 

ix 
List of Figures continued. 

Figure Page 

16 Frequency distribution of hourly-averaged SOz and NOZ concentrations at 40 

Dauphin Island during the study period . 

17 Dauphin Island 3-hour block average SOZ annual trends . 47 

18 Dauphin Island 24-hour block average SOZ annual trends . 48 

19 Dauphin Island 3-hour block average NOz annual trends . 49 

20 Dauphin Island 24-hour block average NOZ annual trends . 50 

21 Dauphin Island diurnal SOz variations as represented by first (dashed), second 51 

(solid), and third (dashed) quartile lines. 

22 Dauphin Island diurnal NOz trends as represented by first (dashed), second 54 

(solid), and third (dashed) quartile lines . 

23 Dauphin Island May 1997 wind (top) and pollution roses (SOz bottom left, NOz 63 

bottom right) . 

24 Dauphin Island June 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 64 

bottom right) . 

25 Dauphin Island July 1997 wind (top) and pollution roses (SOZ bottom left, NOz 65 

bottom right) . 

26 Dauphin Island August 1997 wind (top) and pollution roses (SOZ bottom left, 66 

NOZ bottom right) . 

27 Dauphin Island September 1997 wind (top) and pollution roses (SOZ bottom left, 67 

NOz bottom right) . 

28 Dauphin Island October 1997 wind (top) and pollution roses (SOz bottom left, 68 

NOZ bottom right) . 

29 Dauphin Island November 1997 wind (top) and pollution roses (SOz bottom left, 69 

NOZ bottom right) . 

30 Dauphin Island December 1997 wind (top) and pollution roses (SOz bottom left, 70 

NOZ bottom right) . 

31 Dauphin Island January 1998 wind (top) and pollution roses (SOz bottom left, 71 

NOZ bottom right) . 

32 Dauphin Island February 1998 wind (top) and pollution roses (SOZ bottom left, 72 

NOZ bottom right) . 

33 Dauphin Island March 1998 wind (top) and pollution roses (SOz bottom left, 73 

NOZ bottom right) . 

x 
List of Figures continued. 

Figure Page 

34 Dauphin Island April 1998 wind(top) and pollution roses (SOz bottom left, NOZ 74 

bottom right) . 

35 May 1997 time series of Breton Island hourly-averaged concentrations and wind 76 

direction . 

36 June 1997 time series of Breton Island hourly-averaged concentrations and wind 77 

direction . 

37 July 1997 time series of Breton Island hourly-averaged concentrations and wind 78 

direction . Missing SOz and NO,, on 11 and 12 July . 

38 September 1997 time series of Breton Island hourly-averaged concentrations and 79 

wind direction . 

39 October 1997 time series of Breton Island hourly-averaged concentrations and 80 

wind direction. SO2 and NO,, missing on 26 October. 

40 November 1997 time series of Breton Island hourly-averaged concentrations and 81 

wind direction. 

41 December 1997 time series of Breton Island hourly-averaged concentrations and 82 

wind direction. 

42 January 1998 time series of Breton Island hourly-averaged concentrations and 83 

wind direction. 

43 February 1998 time series of Breton Island hourly-averaged concentrations and 84 

wind direction. Missing air quality data on days 20-22, 23-25, 26-27, and 28 . 

44 March 1998 time series of Breton Island hourly-averaged concentrations and 85 

wind direction. SOZ data has been corrected for an offset . 

45 April 1998 time series of Breton Island hourly-averaged concentrations and 86 

wind direction. SOZ and NO,, data missing on days 6 and 23-24 April . SOZ 

corrected for offset to 21 April. 

46 May 1998 time series of Breton Island hourly-averaged concentrations and wind 87 

direction. 

47 June 1998 time series of Breton Island hourly-averaged concentrations and wind 88 

direction. 

48 July 1998 time series of Breton Island hourly-averaged concentrations and wind 89 

direction. 

49 Frequency distribution of Breton Island hourly-averaged pollutant 90 

concentrations recorded during this study period . 

50 Breton Island annual SOz trends based on 3-hour block averages. 99 

xi 
List of Figures continued. 

Figure Page 

51 Breton Island annual SOZ trends based on 24-hour block averages. 101 

52 Breton Island annual NOz trends based on 3-hour block averages. 103 

53 Breton Island annual NOz trend based on 24-hour block averages. 105 

54 Breton Island diurnal SOz trends as represented by first (dashed), second (solid), 107 

and third (dashed) quartile lines. 

55 Breton Island diurnal NOz trends as represented by first (dashed), second (solid), 110 

and third (dashed) quartile lines. 

56 Breton Island May 1997 wind (top) and pollution roses (SOZ bottom left, NOz 115 

missing) . 

57 Breton Island June 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 116 

bottom right) . 

58 Breton Island July 1997 wind (top) and pollution roses (SOZ bottom left, NOz 117 

bottom right) . Note that Hurricane Danny occurred during this month. 

59 Breton Island September 1997 wind (top) and pollution roses (SOZ bottom left, 118 

NOz bottom right) . 

60 Breton Island October 1997 wind (top) and pollution roses (SOZ bottom left, 119 

NOZ bottom right) . 

61 Breton Island November 1997 wind (top) and pollution roses (SOZ bottom left, 120 

NOz bottom right) . 

62 Breton Island December 1997 wind (top) and pollution roses (SOz bottom left, 121 

NOz bottom right) . 

63 Breton Island January 1998 wind (top) and pollution roses (SOz bottom left, NOZ 122 

bottom right) . 

64 Breton Island February 1998 wind (top) and pollution roses (SOz bottom left, 123 

NOz bottom right) . 

65 Breton Island March 1998 wind (top) and pollution roses (SOz bottom left, NOZ 124 

bottom right). 

66 Breton Island April 1998 wind (top) and pollution roses (SOZ bottom left, NOz 125 

bottom right) . 

67 Breton Island May 1998 wind (top) and pollution roses (SOZ bottom left, NOz 126 

bottom right) . 

68 Breton Island June 1998 wind (top) and pollution roses (SOz bottom left, NOZ 127 

bottom right) . 

xii 
List of Figures continued. 

Figure Page 

69 Breton Island July 1998 wind (top) and pollution roses (SOz bottom left, NOz 128 

bottom right) . 

70 A classification scheme for synoptic weather types affecting New Orleans, 134 

Louisiana and the northeast Gulf of Mexico (after Muller, 1977) . 

71 Comparison of monthly mean SOZ (top) and NOz (bottom) values recorded at 137 

Breton and Dauphin Islands during the study period . 

72a Time series of 1996 24-hour block averaged SOz at Breton and Dauphin Islands. 138 

72b Time series of 1996 24-hour block average NOz at Breton and Dauphin Islands. 139 

72c Time series of 1997 24-hour block averaged SOz at Breton and Dauphin Islands. 140 

72d Time series of 1997 24-hour block averaged NOZ at Breton and Dauphin Islands. 141 

72e Time series of 1998 24-hour block averaged SOz (top) and NOZ (bottom) at 142 

Breton and Dauphin Islands. 

73a 0700 EST surface weather maps for 28-30 September 1997 from NOAA Daily 143 

Weather Map Series . 

73b Meteorological and air quality values observed at Breton and Dauphin Islands 144 

on 28-30 September 1997. 

74a 0700 EST surface weather maps for 15-17 October 1997 from NOAA Daily 145 

Weather Map Series . 

74b Meteorological and air quality values observed at Breton and Dauphin Islands 146 

on 15-17 October 1997 . 

75a 0700 EST surface weather maps for 14-18 December 1997 from NOAA Daily 147 

Weather Map Series . 

75b Meteorological and air quality values observed at Breton and Dauphin Islands 148 

during 14-18 December 1997 . 

76a 0700 EST surface weather maps for 22-24 January 1998 from NOAA Daily 149 

Weather Map Series . 

76b Meteorological and air quality values observed at Breton and Dauphin Islands 150 

on 22-24 January 1998. 

77 Aerial photographs (color infrared) of the northernmost part of Breton Island 152 

taken on 9 December 1996 (top) and 11 January 1999 (bottom). The Kerr 

McGee facility is visible as the small circular object on the inside of the island . 

Top of photos is oriented approximately to the northeast. 

xiii 
List of Figures continued. 

Figure Page 

78 Determining overwater mixing height from the dewpoint depression at the 158 

surface or from surface and cloud-top temperatures based on atmospheric 

thermodynamics (see text for explanation) . 

79 Approximate locations of NOAA buoys and C-MAN stations used in this 160 

analysis. 

80 Frequency of occurrence of stability classes for three NOAA stations and Breton 160 

Island during the period of May 1997 through July 1998 . 

81 Monthly statistics of air and water temperatures at Breton Island and two NOAA 163 

buoys. Vertical lines are standard deviation at Breton. 

82 The stability classes as a function of wind speed and air-sea temperature 164 

difference (from Hsu, 1992). 

83 Monthly statistics of stability characteristics and frequency of occurrence of free 165 

convective conditions at Breton Island and two NOAA buoys. Vertical lines are 

standard deviation at Breton . 

84 A relationship between Z/L and the bulk Richardson number, Rb, based on 166 

measurements from a continental shelf environment by Donelan et al . (1997) . 

85 Observed turbulence intensities at Breton Island compared to the relationship 167 

found for the North Sea. 

86 Lateral (crosswind) turbulence intensities at Breton Island compared to the 168 

relationship for the North Sea (see text for explanation) . 

87 A demonstration of LCL (mixed height) from cloud-top temperature using data 171 

obtained over Breton Island on 4 August, 1998 at approximately 1500 GMT 

(1000 LT) . 

88 Thermodynamic and boundary layer profiles of 3 August 1998, 1619 CDT 172 

radiosonde over Breton Island. "-line is 8, X-line is q, dashed line is 8v. 

89 Thermodynamic and boundary layer profiles of 3 August 1998, 1804 CDT 173 

radiosonde over Breton Island . Lines as in Fig. 88 . 

90 Thermodynamic and boundary layer profiles of 3 August 1998, 2002 CDT 174 

radiosonde over Breton Island . Lines as in Fig. 88 . 

91 Thermodynamic and boundary layer profiles of 3 August 1998, 2157 CDT 175 

radiosonde over Breton Island . Lines as in Fig. 88 . 

92 Thermodynamic and boundary layer profiles of 4 August 1998, 0541 CDT 176 

radiosonde over Breton Island . Lines as in Fig. 88. 

xiv 
List of Figures continued. 

Figure Page 

93 Thermodynamic and boundary layer profiles of 4 August 1998, 0802 CDT 177 

radiosonde over Breton Island . Lines as in Fig. 88. 

94 Thermodynamic and boundary layer profiles of 4 August 1998, 1000 CDT 178 

radiosonde over Breton Island . Lines as in Fig. 88. 

95 Thermodynamic and boundary layer profiles of 4 August 1998, 1217 CDT 179 

radiosonde over Breton Island . Lines as in Fig. 88. 

96 Thermodynamic and boundary layer profiles of 4 August 1998, 1415 CDT 180 

radiosonde over Breton Island . Lines as in Fig. 88 . 

97 One-to-one comparison of LCL heights versus mixed heights from profile and 181 

computed by Eq. (16) . 

98 Variations of monthly mean mixed heights computed for Eq. (16) over the 182 

southeastern Louisiana coast and eastward over the BNWA. 

99 Stable mixed layer height nomogram for air temperature of 19°C . Lines indicate 183 

temperature difference (Tai, - Ts~;,) . 

xv 

LIST OF TABLES 

Table Page 

1 Dauphin Island SOZ Monitor Zero Values 6 

2 Dauphin Island SOz Monitor Precision Values 6 

3 Dauphin Island SOz Monitor Accuracy Values 7 

4 Dauphin Island NO., Monitor Zero Values 9 

5 Dauphin Island NO, Monitor Precision Values 9 

6 Dauphin Island NO, Monitor Accuracy Values 10 

7 Dauphin Island NOz Precision Values 12 

8 Dauphin Island NOZ Accuracy Values 13 

9 Percent Data Return for Air Quality - Dauphin Island (* indicates < 75% 14 

complete) 

10 Breton Island SOZ Monitor Zero Values 18 

11 Breton Island SOz Monitor Precision Values 19 

12 Breton Island SOz Monitor Accuracy Values 20 

13 Breton Island NO,, Monitor Zero Values 21 

14 Breton Island NO,, Monitor Precision Values 22 

15 Breton Island NO,, Monitor Accuracy Values 23 

16 Breton Island NOZ Precision Values 24 

17 Breton Island NOZ Accuracy Values 25 

18 Percentage Air Quality Data Return - Breton Island (* indicates < 75% complete) 26 

19 Dauphin Island SOZ Maximums and Averages (ppb) based on 1 Hour Block 41 

Averages` 

20 Dauphin Island NOz Maximums and Averages (ppb) based on 1 Hour Block 44 

Averages 

21 Dauphin Island SOz Maximums (ppb) 58 

22 Dauphin Island NOz Maximums (ppb) 60 

23 U.S. Federal Primary and Secondary Ambient Air Quality Standard 61 

24 Frequency Distribution of Dauphin Island Top 10% Concentrations 62 

xvii 
List of Tables continued. 

Table Page 

25 Breton Island SOZ Maximums and Averages (ppb) based on 1 Hour Block 91 

Averages 

26 Breton Island NOZ Maximums and Averages (ppb) based on 1 Hour Block 95 

Averages* 

27 Breton Island SOZ Maximums (ppb) 129 

28 Breton Island NOZ Maximums (ppb) 131 

29 Breton Island Top 10% Frequency Distribution by Month and Direction 133 

30 Frequency of Occurrence of Synoptic Weather Types Associated with Peak 135 

Pollutant Days at Breton Island 

31 Summary of Breton and Dauphin Islands Monthly Air Quality Values (ppb) 136 

xviii 
ACKNOWLEDGMENTS 

The successful execution and completion of this field measurement program would not have been 

possible without the assistance of both the Alabama Marine Resources Division and the KerrMcGee Corporation, who provided facilities for our monitoring stations . We especially recognize 

Kerr-McGee for preparing a second location for us following damage from Hurricane Danny. The 

staffs of Southern Seaplane and the fishing camp Chandeleur Islander provided logistic support for 

our service trips to Breton Island . The field technicians of the Coastal Studies Field Support Group 

deserve our gratitude for their efforts to install and maintain the monitoring stations - particularly 

Mr. Bill Gibson and Mr. Steve Dartez, the Chief Technicians for Dauphin and Breton Islands, 

respectively . Finally, thanks to Dr. William Hutzell and Dr. Alexis Lugo-Fernandez, our COTRs 

at the MMS New Orleans for their guidance and support. 

xix 

I. Introduction 

Ambient air quality conditions existing over coastal areas bordering the northeast Gulf of 

Mexico have come under greater scrutiny in recent years. Increases in both the population along 

the coast and in offshore energy production have raised concerns that emissions from these various 

source areas may be impacting the fragile habitats indigenous to these shoreline environments. This 

is especially critical as portions of this coastal region contain protected wildlife areas, and have been 

designated as Class I (the Breton National Wildlife Area (BNWA)) by the U.S . Congress. For these 

areas, the Prevention of Significant Deterioration (PSD) restrictions are applicable. 

Since 1993, the Coastal Studies Institute of Louisiana State University has deployed several 

field programs to measure ambient air quality and meteorology at stations in the Delta National 

Wildlife Refuge, the BNWA, and the Gulf Islands National Seashore. The majority of this data 

record has been analyzed and discussed in three previous Minerals Management Service Reports 

(e.g., Hsu, 1995b; Hsu, 1996; and Hsu and Blanchard, 1998) . The first two Reports documented 

data collected during short-term summer deployments (July to September 1993 and 1994, 

respectively) . The last of these was an Interim Report which detailed aspects of the long term 

records obtained at Breton (October 1994 to April 1997) and Dauphin (March 1996 to April 1997) 

Islands in the northeast Gulf of Mexico (see Fig . 1 for locations). This document will build upon 

those prior findings by presenting data collected during the period of May 1997 through July 1998, 

the final phase of our field program . 

The annual arithmetic means of SOZ and NOz concentration recorded at Dauphin Island 

during the study period were 2 .3 ppb and 4.4 ppb, respectively . These values are less than 10% of 

the National Ambient Air Quality Standards. For both pollutants, hourly concentrations were less 

than 4 ppb over 50% of the time . Annual trends show slight increases in both SOZ and NOz during 

the fall and winter months. Median SOz values show little variation diurnally, while NOZ often 

exhibits a peak in the morning hours. Maximum 1- and 3-hour average concentrations of both 

pollutants are mostly associated with north and northeast wind directions, and occasionally west 

winds (particularly for NOz). 

For the Breton Island monitoring station, calculated annual arithmetic means were 1 .2 ppb 

and 6.2 ppb for SOz and NOz, respectively . During more than half the study period, hourly 

concentrations of both pollutants were less than 6 ppb. The NOZ data, however, showed greater 

frequency of higher concentrations than at Dauphin, with values more than 20 ppb recorded about 

5% of the time. Annual trends of average concentrations for SO2 and NOZ show a very slight 

increase in the fall and winter months . Median SOZ values are very low and are generally consistent 

throughout the day, while median NOz usually shows a slight morning peak. An opposite 

dependency of maximum concentrations and wind direction is observed here, with peak SOZ 

associated with north winds, and peak NOz with winds from southwest and west. Higher SOz 

concentrations are more likely to be observed under Continental High and Frontal Overrunning 

synoptic conditions (see, e.g ., Muller 1977) ; and higher NOz under Gulf Return, Frontal 

Overrunning, or Continental High. All average and maximum values obtained at Breton are well 

below the National Standards. Note that comparisons of the observed pollutant concentrations with 

1 
PSD increments are not valid since the baseline concentrations were unavailable for Breton and 

Dauphin Islands. 

Concentrations of S02 at Dauphin were higher than those at Breton for both averages and 

maximums. Average NO2 values were similar, with maximums frequently being higher at Breton. 

The Breton N02 maximums often result from short-duration (less than one day) episodes of high 

NO, with NOZ concentrations exceeding 30 to 40 ppb. These events are observed several times 

each month. 

Characteristics of dispersion and the atmospheric boundary layer prevailing over the BNWA 

are detailed. Included are methods for determining the drag coefficient, stability category, vertical 

and cross-wind turbulence intensities, the vertical eddy diffusivity, and the mixed layer height under 

both stable and unstable conditions . Slightly unstable conditions are shown to dominate in the study 

area with free convection occurring nearly 4 to 15% of the time. Monthly mean mixed heights 

ranged from about 375 to 775 m. Analysis of radiosonde data obtained over Breton Island verifies 

a relationship between surface dewpoint depression and lifting condensation level, or mixed height, 

at this location. 

Figure 1 . Advanced Very High Resolution Radiometer (AVHRR) satellite thermal image 

showing the approximate locations of our two air quality monitoring stations 

(courtesy of Buddy Martin, Earth Scan Lab, Louisiana State University) . 

2 
II . Data Acquisition and Processing 

A. Overview 

During the period of May 1997 through July 1998, near-continuous monitoring of ambient 

air quality (SOZ and NOX) was conducted at two near-shore stations ; one at Breton Island in the 

Chandeleur chain, and the other at Dauphin Island near the opening of Mobile Bay (see Fig. 1) . 

Measurements at Breton Island were further complemented by a suite of standard meteorological 

sensors. The stations were designed to operate autonomously by employing Campbell Scientific 

CR-10 dataloggers with high capacity storage modules. The air quality monitors were scanned at 

10-second intervals, and a five-minute average was recorded (giving 12 samples / hour) . Most 

meteorological parameters were recorded on the hour; however several intervals were applied for 

the turbulence (uvw) data (15 and 30 minute averages) . The storage modules were downloaded 

during regular service trips, at which time the memory would be cleared and the system reinitialized. 

These stations were located in an attempt to best capture the spatial and temporal 

characteristics of ambient air quality and meteorology over the northeast Gulf of Mexico . In reality, 

site selection was primarily governed by the instrumentation's requirements for power and 

environmental control. While Dauphin Island is near enough to the mainland for commercial power, 

facilities at Breton Island were dependent upon power produced by diesel generators on site. 

Surface and marine vehicular traffic was also present at both locations . Hence, it is inevitable that 

these factors contributed to the recorded air quality records to some degree. 

B . Dauphin Island 

Air quality instrumentation at Dauphin Island was housed within the Alabama Marine 

Resources Division building on the east end of the island (see Fig. 2 for an approximate layout of 

the facility) . Primary station components were Monitor Labs, Inc. ML 9850 SOz analyzer, ML 

9841 A NO,, analyzer, and an Environics Series 100 Multi-Gas Calibrator. All of these units are 

designated as an "equivalent method" for monitoring by the U.S. EPA, as defined in 40 CFR Part 

53 (1994) . Minimal detectable concentrations by the analyzers was approximately 1 ppb. 

A Coastal-Marine Automated Network (C-MAN) station, DPIA 1, is maintained by NOAA 

at Dauphin Island, less than 3 miles from our air quality monitors. Meteorological records obtained 

during this reporting period at DPIA1 were downloaded from the National Data Buoy Center 

(NDBC) website, and integrated with the air quality files during post-processing . 

Calibration of the air quality monitors was achieved through gas phase titration, in which a 

traceable gas standard is diluted with pure air or ozone to generate multiple known concentrations 

(see, e.g ., 40 CFR, App. B, 1994) . If functioning properly, the monitor should produce a linear 

response, hence accuracy is consistent from low to high concentrations. For a more detailed 

description of servicing routines and calibrations, see the Interim Report (Hsu and Blanchard, 1998) . 

3 
N 

------------------ Boat Dock Area 

Rail uoisc 

Sample Intake 

Sample Line (about 50') ----------fl I Ramp u 

Sample Intake About 

2' Above Roof Level ~ I Q 

S02 / NOx Monitors 

Alabama Marine Resources Bldg . 

Dauphin Island, AL 

Figure 2. Layout of air quality monitoring 

station at Dauphin Island (distances 

are approximated) . 

Dauphin Island servicing dates and significant operational notes recorded during this 

reporting period are as follows: 

May 13, 1997 Filters changed and cleaned, calibration. 

June 12, 1997 Filters changed and cleaned, calibration. 

July 16, 1997 UV filters cleaned, internal and external filters changed, charcoal changed, 

leak test, flow check, calibration. 

September 12, 1997 Calibration. 

September 26, 1997 Filters replaced and cleaned, flow check, calibration. 

November 6, 1997 Units cleaned and leak tested, vacuum pump on NOX monitor weakening but 

still within acceptable limits, calibration. 

November 25, 1997 Discovered bad o-rings while working on NOX monitor pump, one replaced, 

calibration. 

4 
December 11, 1997 O-rings replaced, improved vacuum reading on NO, monitor, calibration. 

January 8, 1998 Remaining o-rings replaced, clean and replaced filters, calibration. 

January 22, 1998 Cleaned both monitors, leak test, flow check on SOz monitor, flow check on 

calibrator, calibration . 

February 4, 1998 Replaced filters, failure of ozone generator in NO, monitor, unit offline, 

calibration of SOZ monitor. 

February 13, 1998 Ozone generator installed in NO, monitor, leak test, calibration. 

February 27, 1998 Filters changed, calibration. 

March 15, 1998 Filters changed, calibration. 

April 2, 1998 Filters changed, calibration. 

April 16, 1998 Filters changed, calibration. 

May 9, 1998 Flow check on calibrator and SOZ monitor, calibration, end of monitoring . 

Results of the SOz monitor calibrations are given in Tables 1 to 3, and those for the NO,, 

monitor in Tables 4 to 8 . Exceptional accuracy is obtained, with mean errors being less than 5%. 

No significant zero or span drift is evident for either monitor. 

The SOz monitor has a built-in function for performing a daily background cycle and 

electronic zero check, hence no zero offsets were applied to the data. Periods in which known power 

outages occurred were removed from the record . Other negative values were either removed or 

converted to zero, depending on the magnitude and duration . Field experience has shown that minor 

power fluctuations can cause this monitor to re-initialize, sometimes producing intervals of bogus 

values until the unit stabilizes. Removed data periods were generally less than 24 hours in duration . 

A consistent offset of 2 - 3 ppb was present in the NOZ channel (see Table 4) during most 

of the study period . In an analysis of air quality data recorded from these stations prior to April 

1997, this was addressed by subtracting the offsets from the recorded values (see Interim Report). 

This method can produce excessive negative values ; also, since NO, NO2, and NO,, each has an 

offset, subtraction may not remove the discrepancies (as evidenced by NOZ / NO,, ratios > 1) . It was 

found that subtracting the hourly averaged NO concentration from the NO,, concentration produced 

a value (computed NOz) whose difference from the recorded NOZ was nearly equivalent to the zero 

offset . Applying this technique to the previous dataset presented in the Interim Report resulted in 

monthly and annual averages within about 1 ppb of those listed . Therefore, for this analysis, the 

computed NOZ value is used . 

5 
Table 1 . 

Dauphin Island SOZ Monitor Zero Values 

Date Actual SOZ 

13 May 1997 2 

12 June 1997 0 

17 July 1997 6 

12 September 1997 -1 

26 September 1997 0 

6 November 1997 1 

25 November 1997 1 

10 December 1997 1 

8 January 1998 1 

22 January 1998 0 

4 February 1998 1 

13 February 1998 1 

27 February 1998 1 

15 March 1998 -1 

2 April 1998 1 

16 April 1998 0 

8 May 1998 1 

Table 2 . 

Dauphin Island SOZ Monitor Precision Values 

Date Expected Actual SOZ % Error 

6 November 1997 107 107 0 .00 

22 January 1998 107 106 -0 .93 

8 May 1998 107 102 -4 .67 

Sum -5 .60 

Mean -1 .g7 

Standard Deviation 2 .47 

Upper 95% Limit 2 .97 

Lower 95% Limit -6.71 

6 
Table 3 . 

Dauphin Island SOZ Monitor Accuracy Values 

Date Expected Actual SOZ % Error 

13 May 1997 207 207 0.00 

428 425 -0.70 

12 June 1997 207 205 -0.97 

428 424 -0.94 

18 July 1997 312 315 0 .96 

207 210 1 .45 

428 428 0 .00 

12 September 1997 230 230 0 .00 

477 475 -0 .42 

26 September 1997 230 233 1 .30 

477 480 0.63 

6 November 1997 331 330 -0.30 

230 232 0.87 

477 477 0.00 

25 November 1997 230 229 -0.44 

477 477 0.00 

10 December 1997 230 228 -0.87 

477 475 -0.42 

8 January 1998 230 229 -0.44 

477 475 -0 .42 

22 January 1998 331 331 0 .00 

230 231 0.44 

477 478 0.21 

7 
Table 3 continued 

Date Expected Actual SOz % Error 

4 February 1998 230 229 -0.44 

477 473 -0.84 

13 February 1998 230 228 -0.87 

477 471 -1 .26 

27 February 1998 230 227 -1 .30 

477 471 -1 .26 

15 March 1998 230 226 -1 .74 

477 467 -2.10 

2 April 1998 230 228 -0.87 

477 469 -1 .68 

16 April 1998 230 226 -1 .74 

477 466 -2 .31 

8 May 1998 331 317 -4 .23 

230 221 -3 .91 

---------- 

476 

-------- 

454 

---------- 

-4.62 

-------- 

Sum -29.23 

Mean -0.77 

Standard Deviation 1 .36 

Upper 95% Limit 1 .90 

Lower 95% Limit -3 .44 

8 
Table 4. 

Dauphin Island NO,, Monitor Zero Values 

Date Actual NO Actual NOz Actual NO, 

13 May 1997 1 2 1 

12 June 1997 1 2 1 

18 July 1997 1 2 1 

12 September 1997 1 2 2 

26 September 1997 0 3 1 

6 November 1997 1 2 1 

25 November 1997 0 3 1 

11 December 1997 -1 3 -1 

8 January 1998 0 3 1 

22 January 1998 0 2 0 

13 February 1998 1 2 -1 

27 February 1998 0 0 -3 

15 March 1998 -1 -1 -3 

2 April 1998 0 -1 -3 

16 April 1998 0 -1 -3 

8 May 1998 1 -1 -2 

Table 5 . 

Dauphin Island NO, Monitor Precision Values 

Date Expected Actual NO Actual NO, % Error % Error 

6 November 1997 100 96 98 -4.00 -2.00 

22 January 1998 100 97 98 -3 .00 -2.00 

8 May 1998 

- - - - - - - 

100 

- - - - - 

98 

- - - - - - 

96 

- - - - - - - 

-2.00 

- - - - 

-4.00 

- - - - 

Sum -9.00 -8.00 

Mean -3.00 -2.67 

Standard Deviation 1 .00 1 .15 

Upper 95% Limit -1 .04 -0 .40 

Lower 95% Limit -4 .96 -4 .93 

9 
Table 6. 

Dauphin Island NO, Monitor Accuracy Values 

Date Expected Actual NO Actual NO, % Error % Error 

13 May 1997 214 213 215 -0.47 0.47 

443 439 448 -0.90 1 .13 

12 June 1997 214 219 222 2.34 3 .74 

443 455 461 2.71 4.06 

18 July 1997 323 322 328 -0.31 1 .55 

214 211 214 -1 .40 0.00 

443 441 447 -0 .45 0.90 

12 September 1997 215 212 216 -1 .40 0 .47 

445 441 452 -0.90 1 .57 

26 September 1997 215 218 224 1 .40 4 .19 

445 462 473 3 .82 6.29 

6 November 1997 309 307 312 -0.65 0.97 

215 213 216 -0.93 0.47 

445 442 446 -0.67 0.22 

25 November 1997 215 211 216 -1 .86 0.47 

445 441 450 -0 .90 1 .12 

11 December 1997 215 213 216 -0 .93 0.47 

445 442 450 -0.67 1 .12 

8 January 1998 215 213 215 -0.93 0.00 

445 443 447 -0.45 0.45 

22 January 1998 309 308 312 -0.32 0.97 

215 213 215 -0.93 0.00 

445 443 448 -0 .45 0.67 

10 
Table 6 continued. 

Date Expected Actual NO Actual NO, % Error % Error 

13 February 1998 215 214 215 -0.47 0 .00 

445 444 448 -0.22 0 .67 

27 February 1998 215 213 213 -0.93 -0 .93 

445 444 446 -0.22 0.22 

15 March 1998 215 213 215 -0.93 0.00 

445 443 449 -0.45 0.90 

2 April 1998 215 213 214 -0.93 -0.47 

445 445 448 0.00 0.67 

16 April 1998 215 214 215 -0.47 0.00 

445 448 450 0 .67 1 .12 

8 May 1998 309 304 306 -1 .62 -0 .97 

215 211 212 -1 .86 -1 .40 

--- - - - - - - - 

445 

-- - - - 

438 

- ---- 

443 

--- - -- 

-1 .57 

-- - - 

-0 .45 

-- - - 

Sum -14.25 30 .66 

Mean -0.40 0.85 

Standard Deviation 1 .22 1 .53 

Upper 95% Limit 1 .97 3 .85 

Lower 95% Limit -2.77 -2.15 

11 
Table 7. 

Dauphin Island NOZ Precision Values 

Date Expected Actual NOZ % Error 

13 May 1997 101 106 4.95 

12 June 1997 103 109 5 .83 

18 July 1997 100 103 3 .00 

12 September 1997 93 103 10.75 

26 September 1997 96 107 11 .46 

6 November 1997 95 100 5.26 

25 November 1997 102 104 1 .96 

11 December 1997 98 103 5 .10 

8 January 1998 95 99 4 .21 

22 January 1998 98 99 1 .02 

13 February 1998 99 100 1 .01 

27 February 1998 98 99 1 .02 

15 March 1998 101 103 1 .98 

2 April 1998 98 100 2.04 

16 April 1998 99 100 1 .01 

8 May 1998 

---------- 

98 

-------- 

100 

---------- 

2.04 

-------- 

Sum 62.64 

Mean 3.92 

Standard Deviation 3.27 

Upper 95% Limit 10 .33 

Lower 95% Limit -2 .49 

12 
Table 8 . 

Dauphin Island NOz Accuracy Values 

Date Expected Actual NOz % Error 

13 May 1997 339 343 1 .18 

12 June 1997 354 356 0 .56 

18 July 1997 340 344 1 .18 

12 September 1997 336 344 2 .38 

26 September 1997 348 358 2.87 

6 November 1997 343 348 1 .46 

25 November 1997 354 355 0.28 

11 December 1997 353 359 1 .70 

8 January 1998 345 349 1 .16 

22 January 1998 341 343 0.59 

13 February 1998 349 350 0.29 

27 February 1998 345 346 0 .29 

15 March 1998 352 355 0.85 

2 April 1998 334 337 0.90 

16 April 1998 347 349 0.58 

8 May 1998 

---------- 

348 

-------- 

351 

---------- 

0.86 

-------- 

Sum 17.13 

Mean 1 .07 

Standard Deviation 0 .74 

Upper 95% Limit 2 .52 

Lower 95% Limit -0 .38 

13 
Table 9 lists the monthly air quality data capture rate for Dauphin Island after processing . 

Only February 1998 falls below 85% complete for NO, due to failure of the ozone generator as 

described above. Other missing data is a result of station maintenance and calibrations, and power 

outages. 

Table 9. 

Percent Data Return for Air Quality - Dauphin Island 

(* indicates < 75% complete) 

Month %S02 % NO,, 

May 1997 95 .7 98 .4 

June 1997 99 .6 99.6 

July 1997 86.6 86.6 

August 1997 98 .8 99.7 

September 1997 96.5 96.5 

October 1997 100.0 100.0 

November 1997 92.5 92.1 

December 1997 96.2 96.6 

January 1998 97 .7 98.1 

February 1998 95 .5 65 .3* 

March 1998 98 .0 98 .0 

April 1998 95 .8 99.0 

C. Breton Island 

During this reporting period, several changes were made both to instrumentation and 

operating procedures at the Breton Island station. These modifications were brought about to 

enhance our measurement capability, and in response to damage incurred from environmental 

conditions, natural and man-made . 

The air quality measurements suite consisted of identical Monitor Labs, Inc. analyzers as 

deployed at Dauphin Island ; here a Monitor Labs, Inc. ML 8550 Gas Calibrator was used . Wind 

speed and direction was obtained from a roof-mounted RM Young Wind Sensor . The air quality 

monitors and datalogging system were located on the third floor of the Kerr-McGee building, with 

the air intake facing roughly northeast (see Fig. 3 for schematic) . 

14 
N 

Air Quality Sampling Site 

X17 

E 

10 m 

I~ iJVW and Met Tower 

Kcrr - McGec 

LJVN' - 9.4 m asl 

--_-- 

Microwave' Power I 

Main Building 

32 m 

Entrance ; __- ; ~ ' 

' .o. ' 

1 

I R'ell Piping ~ 

-------

Kerr - McGee 

Artificial Island 

Breton Island 

NOT TO SCALE 

Seaplane Dock 

Figure 3 . Schematic of the Kerr-McGee facility on Breton Island 

showing location of monitoring site following Hurricane 

Danny. 

In early June 1997, a meteorological tower was installed inside of the large pier extending 

from Kerr-McGee. It was instrumented with a RM Young Gill UVW sensor (-9.4 m asl), air 

temperature and relative humidity sensors (- 7.9 m asl), atmospheric pressure (- 6 m asl), and water 

temperature at approximately -1 m depth. These sensors were connected to a separate datalogger 

within a weatherproof box on the pier. 

Approximately six weeks later, Breton Island endured the full force of Hurricane Danny. 

Five-minute average wind speeds of over 30 m s-' were recorded for several hours . The storm 

inflicted considerable damage to the Kerr-McGee facility, as well as to several houseboats and 

camps present nearby . Significant changes to the island's topography were produced. Power was 

lost early, but fortunately the only damage to our equipment was bent mounts on the wind sensors. 

On the other hand, in view of condition of the Kerr-McGee main building, it was decided that no 

repairs would be made and power would not be restored . Major equipment was removed from the 

island . 

15 
By the end of August, 1997, Kerr-McGee had prepared another location for our monitoring 

station - a small portable building which they had powered and air-conditioned specifically for our 

study program. The air quality intake was nearer to ground level (about 4 m) and to the generator 

shed (to the south-southeast) ; but the building was much better regulated both for power and 

environmental conditions . The meteorological tower was re-deployed, with the addition of the RM 

Young Wind Sensor to the tower (about 4 .9 m asl) . 

As described in the Interim Report, fluctuations in voltage and power outages continued to 

affect operations at Breton Island . Much of May and June 1997 NO,, data was lost due to electronic 

damage to the monitor. Power spikes were better controlled following installation in the new 

building, however prolonged outages were noted in February and July 1998 . 

Like Dauphin Island, monitoring at Breton was scheduled to conclude at the end of April 

1998. Considering the generally low data capture rate obtained at Breton, monitoring was allowed 

to continue through July 1998. A data gap occurred in June 1998 due to full memory between 

servicings. 

Service dates and notes from the Breton Island station log are as follows : 

May 9, 1997 Both monitors found malfunctioning, changed power inverter, SOZ corrected, 

NO,, offline, SOZ calibration . 

June 4, 1997 NO,, re-installed, meteorological tower installed, calibration. 

June 10, 1997 Discovered logging software error, no air quality data collected since 3 June, 

corrected. 

June 24, 1997 Flow check of calibrator, calibration. 

July 10, 1997 Installed new mast and RM Young Wind Sensor on roof of building, 

calibration. 

July 23, 1997 Site inspection following Hurricane Danny on 18 July. All power lost; data 

downloaded and systems disconnected. 

August 28, 1997 Station re-deployed in new location . Flow check of calibrator and monitor 

calibration. 

September 19, 1997 Calibration. 

November 4, 1997 Calibration begun but failure of zero air pump . 

November 7, 1997 Repaired pump installed - problem remains. Discovered low line voltage. 

Kerr-McGee personnel adjust generator. Calibration begun and pump stops 

again. Power drop seen. Found that generator has worn spot near 110 volts, 

16 
vibration of unit keeps output voltage fluctuating. Generator set up to 115 

VAC. All electronic setting on SOz monitor re-set . Calibration completed. 

December 20, 1997 NO, monitor pump changed, leak test, calibration. 

January 18, 1998 Flow check of calibrator, calibration. 

February 5, 1998 Calibration. 

February 18, 1998 No communication with meteorological datalogger . Logging program lost -

reloaded. Recorded data ended on 11 February. Air quality monitor's lens 

cleaned, ozone generator in NO., replaced, leak test, calibration. 

March 13, 1998 Found electronic settings on SOZ monitor zeroed - reset. Monitor appeared 

to have lost settings following repeated power outages at end of February. 

NO,, monitor also required adjustment, calibration. 

April 21, 1998 Meteorological program re-installed, zero offset on SOZ adjusted, replaced 

PMT, ozone generator, and vacuum pump in NO,, monitor, calibration . 

June 22, 1998 Calibration gas cylinder changed and quick purge of system attempted, flow 

check of calibrator, resulting calibration bad due to insufficient time for 

system purge, linearity of monitors good; no setting changed on either unit. 

August 3, 1998 Final calibration before station removal. 

Results of the monitor calibrations are given in Tables 10 - 17. As expected, slightly higher 

errors are seen throughout the record, however mean errors remain below 5%. As described above, 

the highest errors occurred following installation of a new span gas cylinder before the system could 

be completely purged . 

Data processing routines applied to this dataset were the same as for Dauphin, i .e ., removal 

of data during known power outages, conversion of negative values to zero, and calculation of NOZ 

from hourly NO,, - NO. Negative values were generally less than 3 ppb. Several data spikes were 

observed following power outages or fluctuations ; these were also removed since they were likely 

due to impurities in the sample line and / or instability in the monitor following re-start . 

Corrective actions were required on the SOz and wind records on multiple occasions. After 

experiencing power failures in February 1998, the SOz monitor would not hold its electronic zero 

setting. Time series of the raw data combined with operator notes showed a negative displacement 

of 13 .5 ppb during 1 - 13 May, 1998, and 5 .7 ppb from May 14 to April 21, 1998, at which time the 

problem was corrected. These offsets were added to the affected data. 

17 
Table 10. 

Breton Island SOz Monitor Zero Values 

Date Actual SOZ 

9 May 1997 0 

4 June 1997 0 

24 June 1997 -1 

10 July 1997 0 

19 September 1997 0 

7 November 1997 1 

20 December 1997 1 

18 January 1998 1 

5 February 1998 1 

18 February 1998 1 

13 March 1998 0 

21 April 1998 1 

22 June 1998 0 

3 August 1998 1 

29 August 1998 1 

18 
Table 11 . 

Breton Island SOZ Monitor Precision Values 

Date Expected Actual SOZ % Error 

9 May 1997 95 93 -2.11 

24 June 1997 100 96 -4.00 

10 July 1997 100 98 -2.00 

19 September 1997 114 118 3 .51 

7 November 1997 114 108 -5 .26 

20 December 1997 114 115 0 .88 

18 January 1998 117 115 -1 .71 

5 February 1998 117 113 -3 .42 

18 February 1998 117 115 -1 .71 

13 March 1998 117 115 -1 .71 

21 April 1998 117 115 -1 .71 

22 June 1998 109 82 -24.77 

3 August 1998 

---------- 

109 

-------- 

100 

---------- 

-8.26 

-------- 

Sum -52.27 

Mean -4.02 

Standard Deviation 6.83 

Upper 95% Limit 9.37 

Lower 95% Limit -17.41 

19 
Table 12. 

Breton Island SOZ Monitor Accuracy Values 

Date Expected Actual SOZ % Error 

9 May 1997 494 493 -0.20 

4 June 1997 494 490 -0.81 

162 158 -2 .47 

24 June 1997 416 416 0.00 

274 269 -1 .82 

168 160 -4.76 

10 July 1997 416 416 0.00 

19 September 1997 414 415 0.24 

222 222 0.00 

7 November 1997 414 416 0.48 

20 December 1997 414 414 0.00 

18 January 1998 417 416 -0.24 

350 349 -0.29 

223 220 -1 .35 

5 February 1998 417 407 -2.40 

18 February 1998 417 416 -0 .24 

13 March 1998 417 416 -0 .24 

21 April 1998 417 416 -0 .24 

22 June 1998 386 293 -24 .09 

328 251 -23 .48 

208 157 -24.52 

3 August 1998 386 365 -5 .44 

328 306 -6.71 

208 192 -7.69 

29 August 1998 414 415 0.24 

222 220 -0.90 

Sum -106.93 

Mean -4.11 

Standard Deviation 7.66 

Upper 95% Limit 10.90 

Lower 95% Limit -19.12 

20 
Table 13 . 

Breton Island NO, Monitor Zero Values 

Date Actual NO Actual NOZ Actual NO,, 

4 June 1997 1 3 3 

24 June 1997 1 2 2 

10 July 1997 0 2 1 

19 September 1997 1 1 2 

7 November 1997 1 2 2 

20 December 1997 1 1 1 

18 January 1998 -1 2 0 

5 February 1998 -1 -1 0 

18 February 1998 0 0 -1 

13 March 1998 0 2 0 

0 2 0 

21 April 1998 -2 6 2 

22 June 1998 -1 5 2 

3 August 1998 0 6 3 

29 August 1998 1 2 1 

21 
Table 14 . 

Breton Island NO, Monitor Precision Values 

Date Expected Actual NO Actual NO, % Error % Error 

24 June 1997 71 69 71 -2 .82 0 .00 

10 July 1997 71 70 70 -1 .41 -1 .41 

19 September 1997 108 106 108 -1 .85 0.00 

7 November 1997 108 103 104 -4.63 -3 .70 

20 December 1997 108 108 108 0.00 0.00 

18 January 1998 112 113 112 0.89 0.00 

5 February 1998 112 123 122 9.82 8 .93 

18 February 1998 112 110 114 -1 .79 1 .79 

13 March 1998 112 91 92 -18 .75 -17 .86 

112 111 111 -0 .89 -0.89 

21 April 1998 112 110 113 -1 .79 0.89 

22 June 1998 112 82 85 -26.79 -24.11 

3 August 1998 

- - - - - - - - - 

112 

- - - - - 

97 

- - - - - - 

100 

-- - - - - - 

-13 .39 

- - - - 

-10.71 

- - - - 

Sum -63 .40 -47.07 

Mean -4.88 -3.62 

Standard Deviation 9.48 8 .87 

Upper 95% Limit 13 .70 13 .77 

Lower 95% Limit -23 .46 -21 .01 

22 
Table 15 . 

Breton Island NO,, Monitor Accuracy Values 

Date Expected Actual NO Actual NOx % Error % Error 

4 June 1997 477 477 477 0.00 0.00 

151 146 146 -3 .31 -3 .31 

24 June 1997 388 385 388 -0.77 0.00 

233 229 230 -1 .72 -1 .29 

118 113 115 -4.24 -2 .54 

10 July 1997 388 388 388 0.00 0.00 

19 September 1997 501 499 502 -0.40 0.20 

348 346 348 -0.57 0.00 

241 240 243 -0.41 0.83 

7 November 1997 501 498 501 -0.60 0.00 

20 December 1997 501 501 502 0 .00 0.20 

18 January 1998 417 417 419 0 .00 0.48 

308 316 313 2 .60 1 .62 

177 176 175 -0.56 -1 .13 

5 February 1998 417 470 473 12 .71 13 .43 

18 February 1998 417 415 416 -0.48 -0 .24 

13 March 1998 417 351 351 -15 .83 -15 .83 

417 415 417 -0.48 0 .00 

21 April 1998 417 417 417 0.00 0 .00 

22 June 1998 416 294 303 -29.33 -27 .16 

307 218 227 -28 .99 -26 .06 

177 123 128 -30.51 -27 .68 

3 August 1998 416 379 381 -8.89 -8 .41 

307 282 283 -8.14 -7.82 

177 158 161 -10.73 -9.04 

29 August 1998 501 499 505 -0.40 0.80 

------ 

241 

----- 

239 

------ 

242 

------ 

-0.83 

-- 

0.42 

Sum 131 .88 112.53 

Mean -4.88 -4.17 

Standard Deviation 10 .19 9.57 

Upper 95% Limit 15 .09 14.59 

Lower 95% Limit -24 .85 -22.93 

23 
Table 16. 

Breton Island NOZ Precision Values 

Date Expected Actual NOz % Error 

4 June 1997 101 108 6.93 

24 June 1997 93 91 -2.15 

10 July 1997 89 88 -1 .12 

19 September 1997 81 81 0.00 

7 November 1997 77 77 0 .00 

20 December 1997 78 76 -2 .56 

18 January 1998 68 67 -1 .47 

5 February 1998 79 76 -3 .80 

18 February 1998 76 76 0 .00 

13 March 1998 58 55 -5 .17 

81 80 -1 .23 

21 April 1998 71 71 0.00 

3 August 1998 50 49 -2 .00 

29 August 1998 95 90 

---------------------------- 

-5 .26 

-------- 

Sum -17.83 

Mean -1 .27 

Standard Deviation 2.97 

Upper 95% Limit 4.55 

Lower 95% Limit -7.09 

24 
Table 17. 

Breton Island NOZ Accuracy Values 

Date Expected Actual NOZ % Error 

4 June 1997 

24 June 1997 

430 

343 

433 

345 

0.70 

0.58 

10 July 1997 240 239 -0.42 

19 September 1997 236 238 0.85 

7 November 1997 218 224 2.75 

20 December 1997 348 346 -0 .57 

18 January 1998 183 179 -2 .19 

5 February 1998 320 321 0 .31 

18 February 1998 293 293 0 .00 

13 March 1998 240 238 -0 .83 

307 310 0 .98 

21 April 1998 293 295 0.68 

3 August 1998 232 234 0.86 

29 August 1998 

---------- 

367 

-------- 

366 

---------- 

-0.27 

-------- 

Sum 3 .43 

Mean 0.25 

Standard Deviation 1 .13 

Upper 95% Limit 2.47 

Lower 95% Limit -1 .97 

25 
Several versions of the meteorological datalogging program were produced during 

development and testing. On 28 August 1997 and 18 February 1998, a version containing an error 

in the wind speed logging was loaded accidentally while in the field. The error resulted in recorded 

wind speed values being off by a factor of 10. Affected periods were 1 September to 7 November 

1997, and 18 February to 20 March 1998. The corrected wind data, along with the rest of the wind 

record, was found to be in good agreement with observations from NOAA buoy 42007 located at 

the northern end of the Chandeleurs. 

As described previously, re-location of the equipment helped to produce a much improved 

data return rate at Breton, as shown in Table 18 . Low values in July and August 1997 were due to 

Hurricane Danny, while June 1998 resulted from a full storage module between servicing . Other 

missing data is from monitor failure, power outages, and station maintenance. 

Table 18 . 

Percentage Air Quality Data Return - Breton Island 

(* indicates < 75% complete) 

Month %S02 % NO,, 

May 1997 79 .7 7 .3 

June 1997 75 .3 66 .9* 

July 1997 34 .5* 51 .2* 

August 1997 0* 0* 

September 1997 83 .2 83 .2 

October 1997 98 .9 98.9 

November 1997 99.0 99.0 

December 1997 99.5 99.5 

January 1998 99.2 99 .2 

February 1998 79.2 81 .9 

March 1998 99.3 99 .3 

April 1998 93 .6 93 .6 

May 1998 100.0 100 .0 

June 1998 56.8* 56.8* 

July 1998 88 .3 88 .3 

26 
III. Analysis and Results 

This section will present a summary of the air quality records obtained at Dauphin and 

Breton Islands during the period of May 1997 through July 1998. All air quality analysis is based 

on 1-, 3-, and 24-hour block averaged data. Station records will be compared, and case studies of 

simultaneous high concentrations discussed. Synoptic weather patterns associated with pollutant 

peaks at Breton Island are determined. Finally, a detailed analysis of boundary layer and dispersion 

meteorology over the BNWA is explained. 

A. Dauphin Island Air Quality 

Hourly air quality data were merged with meteorological records from the NOAA C-MAN 

station DPIA1. Figures 4 - 15 depict the monthly time series for wind direction, SO2, and NOz, 

along with servicing days . The majority of SOZ and NOZ values fall within the 0 - 10 ppb range, 

with NOz concentrations being slightly higher in general. A frequency distribution of all hourly 

values shows that almost 70% of the SOZ values are less than 2 ppb, while NOZ concentrations were 

less than 4 ppb approximately 60% of the time (Fig. 16) . 

Annual statistics were based on 8417 samples for SOz (96.1% complete) and 8267 samples 

for NOZ (94.4% complete) . The annual arithmetic mean S02 concentration was 2 .28 ppb with a 

standard deviation of 3 .18 ppb and a 95% confidence level of 0 .068 . For NO2, the mean was 4.38 

ppb with a standard deviation of 4.02 ppb and 95% confidence level of 0.087 . These values 

compare well with those listed in the Interim Report (i .e ., 1 .86 ppb for SOZ and 4.58 ppb for NOZ) 

(Hsu and Blanchard, 1998) . 

Monthly averages and maximums for SOZ and NOZ are listed in Tables 19 and 20, 

respectively . A slight increase in average concentration of both pollutants is seen during the late fall 

- early winter months of October - December 1997 . The wintertime peaks, particularly for NO2, 

were also evident in the 1996-1997 data as shown in Figs . 17 - 20, the 3- and 24-hour average time 

series for S02 and N02. 

First, second, and third quartile values are used to show the diurnal variations of SOz and 

NOz concentrations in Figs. 21 and 22, respectively . Median (2"d quartile) SOz values are generally 

1 - 2 ppb; a slight peak is often observed in the mid-morning to mid-day hours . Median NOZ values 

range from 1 - 7 ppb. A distinct peak is seen in the early morning (about 0700 CST), with minimum 

values in the late afternoon. This distribution is expected due to photoabsorption of solar radiation, 

which can cause NOz to dissociate into NO and O molecules (Bouble et al ., 1994). 

27 
N 

00 

360 

315 

,0 270 

225 

180 

135 

90 

45 

0 

24 

22 

20 

18 

16 

14 

12 

O 10 

8 

6 

4 

2 

0 

Figure 4 . 

Dauphin Island - May 1997 

18 

16 

14 

12 

10 p~` 

8 ~' 

6 

4 

2 

May 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . SOz missing on 15 May. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
360 

315 

0 270 

225 

6i 

180 

135 

90 

45 

0 12 

10 

N 

is 

16 

14 

.a 12 

a 

p. 10 

N 

O 

z 

4 

2 

0 

8 ,Q 

a 

6 A" 

4 

2 

Figure 5 . June 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from DPIA1 . 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - June 1997 
w 

O 

360 

315 

,0 270 

y 225 

~. 

180 

135 

90 

45 

0 

28 

24 

20 

16 

N 

12 

z s 

4 

r 

t 

r 

t 

Service Cal 

a~ Lk 

A A 

mob 

i i i i 

1 

0 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - July 1997 

44 

40 

- 36 

32 

28 

24 0. 

- 20 

16 

12 

.g 

-4 

-0 

Figure 6. July 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . Air quality data missing on 4 July and in mid-month as depicted . 
360 

315 

0 270 

225 

180 

135 

90 

45 

0 14 

12 

10 

8 R' 

R. 

6 ~' 

4 

w 

20 

18 

16 

14 

12 

r, 10 

O s 

z 

4 

2 

0 

Figure 7 

2 

0 

August 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . SOZ data missing on 18 August. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - August 1997 
w 

N 

360 

315 

0 270 

225 

180 

135 

90 

45 

0- 

24 

20 

16' 

a 

N 12 

O 

z s4 

0 

1 

Ulr 

I I I I , I I I I I I h Y or. - - - - i ; - - 

i i 

i 

i 

LA A i . i 

Cal 

- 

i i 

40 

36 

32 

28 

- 24 R

20 

16 

12 

-8 

-0 

3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - September 1997 

Figure 8 . September 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . 
w 

w 

360 

315 

C 

0 270 

y 225 

~ . 

180 

135 

90 

45 

0 

30 

27 

24 

21 

18 

r, 15 

O 12 

9 

6 

3 

0 

Dauphin Island - October 1997 

Figure 9. 

40 

36 

32 

28 

24 a 

20 p" 

16 

12 

8 

4 

0 

October 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
w 

360 

315 

,0 270 

225 

~. 

180 

135 

90 

45 

0 

30 

27 

24 

21 

18 

r, 15 

12 

9 

6 

3 

0 

Dauphin Island - November 1997 

Figure 10. 

30 

27 

24 

21 

18 a 

15 °" 

12 

9 

6 

3 

0 

November 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . NO, missing on 24 November. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
w 

360 

315 

0 270 

225 

c. 

180 

135 

90 

45 

0 

55 

50 

45 

40 

35 

a 30 

25 

z Zo 

15 

10 

5 

0 

Figure 11 

. 0 .. 

U 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - December 1997 

55 

50 

45 

40 

35 a 

30 a 

25 

20 

15 

10 

5 

0 

December 1997 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA 1 . Missing SOZ data on 29 December. 
360 

315 

,0 270 

225 

~. 

180 

135 

90 

45 

0 24 

20 

16 ~ 

a 

12 

8 

w 

35 

30 

25 

 20 

15 

z io 

s 

0 

4 

0 

Figure 12 . January 1998 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA1 . SOZ data missing on 5 and 21 January, NO, missing on 7 and 21 January. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - January 1998 
w 

360 

315 

,0 270 

225 

180 

135 

90 

45 

0 

24 

20 

a~ 16 

12 

O 

z s 

4 

0 

Figure 13 . 

V 

T '1 

i Cal i 

i 

i i 

i 

~ . . ~ - I W- I 

Cal Service " ~ 

b------------------------ 

b~Cal 

1 Missing Data 

NOx Only 

Ll . . I . . . . . . . . ~ L4j 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 

Dauphin Island - February 1998 

24 

20 

16 

a 

12 

8 

4 

0 

February 1998 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIAI . NO,, missing on 3 and 16 February, SOz on 16 and 17 February. 
w 00 

360 

315 

0 270 

225 

~. 

180 

135 

90 

45 

0 

20 

16 

12 

N 

O g 

4 

0 

Figure 14. 

1 

f 

i 

i i 

Cal 

i i 

1 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - March 1998 

18 

15 

12 

c+. 9 

6 

3 

0 

March 1998 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIA1 . SOz and NO, missing on 20 March. 
360 

315 

,0 270 

y 225 

~. 

180 

135 

90 

45 

0 14 

12 

10 

g a 

a 

6 ~' 

4 

w 

15 

12 

a 9 

a 

N 

O 

3 

0 

Figure 15 . 

2 

0 

April 1998 time series of Dauphin Island hourly-averaged concentrations and wind direction from 

DPIAI. SOZ data missing on 13 - 14 April. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Dauphin Island - April 1998 
50 

45 

40 

35 

0 30 

25 

20 

15 

10 

5 

0 

16 

14 

12 

0 10 

v 

C 

w 6 

4 

2 

0 

Figure 16. 

Dauphin Island SO, ppb 

Based On Hourly Block Averages 

Period: May 1997 - April 1998 

>251 

0.5 2.5 4.5 6.5 8.5 10.5 12.5 14.5 16.5 18.5 20 .5 22.5 24.5 

Dauphin Island NO, ppb 

Based On Hourly Block Averages 

Period : May 1997 - April 1998 

>25 I 

0.5 2.5 4.5 6.5 8.5 10.5 12.5 14.5 16.5 18 .5 20.5 22.5 24.5 

Frequency distribution of hourly-averaged SO2 and NOZ concentrations at Dauphin 

Island during the study period . 

40 
Table 19 . 

Dauphin Island SOZ Maximums and Averages (ppb) based on 1 Hour Block Averages` 

May 1997 June 1997 July 1997 August 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 2.3 0.8 1 .7 0.6 4.3 1 .4 1 .4 0 .8 

2 0.2 0.0 11 .1 1 .8 13 .9 2.8 8 .3 2 .2 

3 1 .6 0.4 6.2 1 .8 11 .5 1 .8 3 .3 1 .1 

4 6.9 2.2 9.7 4.7 42.5 4.0 3 .9 1 .1 

5 2.6 1 .0 4.1 0.8 14 .7 2.2 2.9 0.7 

6 2.6 1 .1 2.1 0.6 1 .5 0.5 3.9 1 .7 

7 2.8 0.6 0.7 0.2 1 .4 0.5 13 .5 5 .4 

8 0.4 0.2 0.6 0.3 12 .3 2.0 7.3 2 .1 

9 9.9 1 .1 1 .0 0.3 12 .2 3 .3 2.7 0 .6 

10 6.0 2.0 1 .6 0.5 16 .2 4.0 1 .1 0 .4 

11 5.8 1 .9 2.4 0.7 25.3 8.6 1 .4 0 .5 

12 2.9 1 .0 1 .2 0.3 13 .0 4.2 2 .6 0 .4 

13 15 .3 4.6 2.7 0.9 5 .6 2.4 0.4 0 .1 

14 1 .5 0.8 0.7 0.2 10 .2 3 .3 2 .0 0 .4 

15 2 .4* 1 .3* 3 .8 1 .3 2.3 0.6 0 .3 0 .1 

16 16 .3 3.2 0.4 0.2 2.4* 0 .9* 0 .4 0 .2 

17 8.7 2.8 1 .9 0.6 0 .4 0.1 

18 0.7 0.3 0.9 0.2 6.3* 6 .1* 1 .7* 0.5* 

19 0.7 0.3 1 .2 0.2 0.7 0.3 

20 0.6 0.4 1 .0 0.2 1 .4* 1 .0* 3 .7 0.7 

21 6.0 1 .5 0.5 0.3 3 .6 0.6 11 .8 2 .8 

22 29 1 .7 4.7 1 .5 1 .5 0.6 12 .5 6.6 

23 3.8 1 .3 7.1 2.3 5.0 1 .5 8 .1 3 .5 

24 0.5 0.2 4.1 0.9 2.0 0.9 7 .8 2 .2 

2 5 0.7 0.2 0J 0.3 4.8 1 .3 6.0 1 .9 

2 6 1 .0 0.4 0.7 0.4 7.4 2.4 4.3 1 .4 

2 7 0.7 0.4 7.8 0.7 9.1 2.3 10.1 2 .7 

28 1 .3 0.3 6.2 1 .2 0.8 0.4 12.6 4.0 

29 0.1 0.0 1 .0 0.5 1 .1 0.6 6.0 3 .0 

3 0 0 .3 0 .1 1 .9 0.5 9.9 0.6 10 .1 4.3 

31 6 .8 1 .7 0.7 0.3 12 .3 4.7 

# Hours 712 717 644 735 

Maximum 16 .3 11 .1 42 .5 13 .5 

Arith-Mean I ~ 1 .1 ~ 0.8 2.0 1 .8 

boxes indicate less than 75% (18 hours) complete. 

41 
Table 19 continued. 

September 1997 October 1997 November 1997 December 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 10 .6 3 .6 17 .2 5.1 0.9 0.5 9.3 3 .1 

2 13 .8 3 .7 8 .9 5.1 7.9 2.5 6.5 2.1 

3 12 .0 3 .7 5 .0 2.3 18.5 3.9 13 .2 1 .7 

4 10 .6 3 .8 10 .2 2.6 21 .3 4.3 3 .8 1 .9 

5 4.6 1 .3 2 .8 0 .9 3 .2* 1 .8* 50.5 3 .6 

6 2.1 1 .1 4.6 1 .2 27 .0 3 .8 

7 5 .0 1 .0 3 .9 1 .6 3 .9* 2.5* 11 .8 3 .4 

8 21 .6 5 .2 1 .4 0 .6 7.0 4.5 4.3 0.8 

9 6.6 2.2 3 .3 0 .5 11 .2 7.4 1 .0 0.2 

10 4.5 1 .6 2 .6 0 .7 20.6 6.5 3 .1 * 1 .2* 

11 5.7* 3.4* 7.6 2 .7 19 .1 8.8 16 .9* 9.6* 

12 13 .2* 3.4* 3 .1 0 .7 3 .2 1 .0 14 .9 9.8 

13 38 .0 7.1 0.9 0.4 3 .3 1 .5 13 .3 6.1 

14 8.3 3 .5 8.0 3 .2 6 .1 1 .8 9.7 2.7 

15 18 .6 6.0 15 .0 6.3 9 .9 3 .1 33 .8 10 .2 

16 18 .0 6.8 15 .2 7 .4 8 .3 3 .2 12 .1 7 .4 

17 13 .6 4.0 12 .0 7.2 12 .6 4.2 9.3 3 .6 

18 11 .0 2.2 18 .9 8 .8 9 .9 3.8 23 .8 4 .5 

19 3.4 0.7 37.1 9.9 19 .0 3.0 1 .1 0 .6 

20 6.6 1 .7 20.1 6.8 2 .7 1 .1 6.0 1 .2 

21 4.4 2.2 35 .4 6.3 0.8 0.5 4.8 1 .1 

22 18 .3 7.8 16.8 7.3 10 .4 1 .6 5.4 2 .3 

23 1 .9 1 .1 12.5 3 .3 29 .3 8.8 6.5 2 .4 

24 0.8 0.4 4.9 1 .0 17 .8 5.9 3 .3 0.9 

25 5.1 0 .7 0.5 0.0 9.9 4.1 14 .5 5 .5 

26 5.7 2 .7 5.1 0.9 8.0 2.3 8.6 5 .4 

27 5.4 1 .9 17 .5 4.1 1 .9 0.7 92 1 .6 

28 16.7 4.8 20.1 5.5 0.8 0.3 11 .4 3 .3 

29 12.6 3 .8 14.9 7.8 1 .9 0.7 8.3 2.5 

30 27.8 6.6 29.0 3.2 5.0 1 .9 11 .4 3 .5 

31 12 .2 3.2 9.8 3 .4 

# Hours 695 744 666 716 

Maximum 38.0 37.1 29.3 50.5 

Arith-Mean 3 .3 3 .8 3 .2 3 .5 

42 
Table 19 continued. 

January 1998 February 1998 March 1998 April 1998 

Day Max Avg Max Avg Max Avg Max Avg 

1 20.0 4.2 3.1 1 .7 4.2 1 .5 13 .7 2 .2 

2 1 .7 1 .0 7.2 1 .1 15 .1 3.0 5 .4 1 .3 

3 1 .8 0.9 4.5 1 .7 6.1 2.3 1 .5 0.7 

4 2.1 1 .2 2.2* 1 .4* 2.6 1 .5 4.4 1 .1 

5 3 .8 1 .5 17 .9 3 .8 0.9 0.5 6.8 3 .4 

6 3 .7 2 .3 12 .1 3 .7 1 .5 0.6 10 .5 4.1 

7 7 .2 1 .0 13 .1 4.8 0.6 0.2 1 .6 0.7 

8 1 .5 0 .6 20.9 5.8 2.0 0.8 1 .3 0.6 

9 7 .1 3 .2 9.7 2.7 2.0 1 .2 4.6 1 .2 

10 8 .6 4.0 1 .4 0.5 5.2 1 .5 2 .9 1 .0 

11 4.1 1 .8 9 .3 1 .9 14.3 5.9 6.1 2.3 

12 2 .4 0.6 11 .8 3.0 5.4 3.8 11 .7 2.9 

13 1 .9 1 .0 7 .6 3.2 17.0 6.5 1 .0 0.6 

14 10 .2 1 .4 17 .2 6.3 1 .7 0.8 1 .0* 0.7* 

15 4.0 1 .2 9 .4 2.9 10.5 2 .4 2.8 1 .5 

16 5 .8 1 .8 2 .2 0 .6 1 .7 0.5 0.5 0.1 

17 3 .5 1 .8 1 .9* 0.9* 0.8 0.6 0.5 0.1 

18 9.6 2.6 7.8 2 .7 2 .7 0.8 1 .2 0.6 

19 16 .4 4.2 6.8 2 .1 2 .8 0.9 2.8 1 .2 

20 8.0 3 .1 52 2 .9 4.5* 1 .0* 9.1 4.1 

21 15 .1 2.3 23.0 2 .8 3 .5 0.7 9.1 4 .3 

22 0.8 0.3 3 .3 1 .1 8 .4 3 .4 8.3 1 .6 

23 3.4 1 .3 4.1 1 .8 8 .8 3 .0 3.8 1 .9 

24 3.5 1 .9 8.1 3 .2 1 .8 0.7 7.9 2 .7 

25 14 .6 4.1 1 .0 0.7 1 .7 0.7 1 .5 1 .0 

2 6 13 .8 2.3 0.8 0.5 1 .3 0.7 1 .4 0.7 

2 7 4.1 1 .8 5.1 2.4 0.8 0.5 0.7 0.3 

28 11 .1 4 .5 12 .0 3 .6 0.8 0.1 0.9 0.3 

2 9 6.2 2 .8 1 .7 0.5 0.8 0.3 

3 0 22.4 6 .1 1 .0 0.6 1 .5 0.3 

31 19.0 5 .2 0.8 0.5 

# Hours 727 642 729 690 

Maximum 22.4 23.0 17 .0 13 .7 

Arith-Mean 2.4 2 .5 1 .5 1 .5 

43 
Table 20 . 

Dauphin Island N02 Maximums and Averages (ppb) based on 1 Hour Block Averages 

May 1997 June 1997 July 1997 August 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 5.0 2.4 4.8 3 .1 15 .6 4.4 8.5 2.8 

2 3.4 2.1 15 .7 5 .3 18 .1 6.8 7.2 3.3 

3 9.1 3.4 14.7 7.5 9.3 5.7 6.2 3.5 

4 5.8 3.5 14.8 7.5 12 .3 6.6 9 .4 3 .8 

5 7.7 2.7 12 .5 3 .8 10 .3 4.9 12 .0 4 .3 

6 22 .1 4.2 5.8 2.9 4.4 2.1 12 .9 4 .5 

7 9 .9 3 .1 5.4 2.6 21 .1 4.4 17 .2 6 .0 

8 3 .0 1 .4 3.3 1 .5 15 .4 5.9 13 .1 3 .6 

9 10 .1 3 .3 5.2 2.9 10 .5 5.6 6 .0 2 .0 

10 7 .3 3 .2 5.9 2.5 19 .9 5.8 10 .4 3 .6 

11 9 .1 3 .8 7.5 3 .8 27 .4 8.0 4.9 2 .3 

12 6 .3 3 .2 6.5 2.3 18 .9 8.6 3 .7 1 .7 

13 11 .3 5 .7 6.2 3.4 12 .4 5.3 5 .2 1 .5 

14 4.7 3 .2 4.4 3.1 12 .8 5.5 12 .9 3 .2 

15 11 .9 4.6 7 .0 3.5 8.0 3.2 2 .4 1 .3 

16 18 .8 5 .7 6 .0 2.5 8 .8* 4.6* 1 .7 0.8 

17 12 .8 4.4 7 .6 2.5 1 .9 0.8 

18 4.2 2 .2 7 .6 3.3 1 .2* 0.9* 6.8 2.3 

19 6.0 2 .6 5 .9 3.7 8.5 3 .3 

20 4.9 2 .8 6 .3 2.9 23.8* 15 .2* 15.0 3 .9 

21 9.2 5 .5 3 .7 2 .3 9.2 4.5 12 .6 4.8 

22 8.3 4.6 4.8 3 .1 12 .3 7.6 12 .8 7.9 

23 8.4 4.8 17 .9 6 .4 13 .6 6.2 10 .8 4.0 

24 5 .5 2.5 6.0 2 .7 13 .0 5 .6 8.5 3.7 

25 4.3 2.3 4.7 2 .3 23.1 5 .2 6.3 3.2 

26 3.9 2.1 6.4 2 .3 12.9 5 .8 12 .4 4.2 

27 4.3 2.2 8.1 3 .8 13.4 4.6 7.7 4.0 

2 8 5.2 2.4 7.2 3 .5 5 .3 2.5 12 .9 6 .4 

29 5.0 2.1 7.9 3 .1 8 .0 3.5 19 .0 6 .4 

30 6.0 2.0 5.4 2.4 5 .8 2.8 8.5 4 .7 

31 11 .8 4.2 5 .0 2.5 12 .3 5 .3 

# Hours 732 717 644 742 

Maximum 22 .1 17.9 27 .4 19 .0 

Arith-Mean 3 .3 3 .4 J ~ 5.1 I I 3 .7 

* boxes indicate less than 75% (18 hours) complete. 

44 
Table 20 continued. 

September 1997 October 1997 November 1997 December 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 8.3 4.6 17 .1 8 .0 7.0 3.9 15 .4 7 .6 

2 7.1 3.7 21 .5 6.6 9.8 5.0 7 .8 5 .4 

3 15 .8 5.3 21 .5 6.5 12 .2 6.4 17 .9 4 .1 

4 9.5 4.7 7.5 3 .7 11 .9 5.0 5.2 3.9 

5 3.6 1 .9 14.1 4.6 13 .3* 6.7* 7.0 4.1 

6 4.1 2.4 10.5 3 .0 19 .5 6.3 

7 7.1 2.2 12 .0 3 .5 8.1* 6.4* 13 .2 6.1 

8 20.8 5.2 7.1 3 .0 12 .2 6.7 7.0 3.7 

9 9.3 3.6 4.9 2 .8 16 .7 10 .2 20.2 5.9 

10 7.4 3.5 6.1 3 .1 23.5 10 .3 9.5* 5 .7* 

11 8 .7* 4 .5* 6.8 3 .2 20.6 8.3 19 .2* 16 .8* 

12 5 .0* 3 .6* 4.7 2 .0 9.0 5.0 21 .2 14 .3 

13 22 .4 6.6 3 .7 1 .8 19 .0 7.9 14 .8 6.7 

14 7.7 4.7 15 .4 6.6 14 .3 7.0 12 .7 3.8 

15 8.0 4.5 14.6 8 .3 11 .5 5.9 27.8 14 .4 

16 15 .4 5.1 19 .8 11 .0 11 .8 5.0 29.8 16 .8 

17 10 .4 4.6 19 .5 10 .9 17 .2 5.1 32 .8 15 .0 

18 8.7 3.8 18 .9 10 .7 26.4 8.3 51 .4 12 .9 

19 6.0 2.6 24.5 9.9 8.5 5.4 20.5 10 .3 

20 12 .7 3.9 26.1 14 .9 8.3 4.7 14 .4 7 .9 

21 9.7 4.7 14.9 7.7 7.3 2.9 8 .3 3 .5 

22 13 .1 5.7 15 .6 9.7 24 .6 8.4 38.8 12 .1 

23 4.5 2.3 11 .5 5 .2 19 .8 8.9 32.8 8 .1 

24 3.9 2.2 10.1 2.8 28 .7 7.3 7 .4 3 .5 

25 8.7 3.8 4.0 2.2 11 .7 6.9 19 .0 9 .4 

26 8.6 5J 5.2 2.5 12 .7 6.0 13 .1 6.4 

27 7.2 4.0 13 .0 5 .5 9.7 4.4 13 .8 4.1 

28 14.2 5.7 21 .5 7.8 12 .0 3.2 11 .5 4.4 

29 11 .4 6 .1 28.0 10.7 6.9 1 .9 7.8 4.1 

30 19.3 7 .1 13 .2 8.1 6.6 4.1 18.2 6.6 

31 21 .7 8.2 12 .5 6.7 

# Hours 695 744 663 719 

Maximum 22.4 28.0 28 .7 51 .4 

Arith Mean 4.3 6.3 6.1 7.6 

45 
Table 20 continued. 

January 1998 February 1998 March 1998 April 1998 

Day Max Avg Max Avg Max Avg Max Avg 

1 8 .5 4.3 10 .6 4.7 5.7 1 .7 10 .3 1 .7 

2 10 .5 5J 3.8 2.6 10.4 3.3 6.3 0.9 

3 11 .3 5 .3 6 .8 4.5 10.0 2.6 2 .9 0.7 

4 9 .5 4.6 5.0* 3 .0* 6.2 1 .3 7.6 2.2 

5 9.1 3 .3 4.1 1 .2 8.6 1 .3 

6 11 .9 3 .0 6.7 1 .5 5 .6 1 .8 

7 5 .7 3 .0 2.4 0.2 4.7 0.6 

8 13 .8 6.0 7.9 2 .0 2.3 0.4 

9 10 .0 6.8 1 .6 0.5 7.8 1 .9 

10 15 .3 7.2 6.1 0.8 3 .3 1 .2 

11 14.0 5 .9 10.0 5 .0 11 .7 3 .0 

12 7.9 3 .4 6.4 2 .3 6.5 1 .0 

13 24.1 8.9 12.5* 8.5* 8 .3 2.6 2.1 0.3 

14 9.8 3 .9 16 .0 5 .9 10 .7 2.4 2.0 0.4 

15 11 .7 4.9 3 .9 1 .4 8 .6 4.0 2.0 0.5 

16 8.5 5.2 14 .3 4.4 7 .1 2.0 0.8 0.1 

17 28 .4 9.0 6.0 3 .3 0.0 0.0 1 .9 0.4 

18 10 .5 4.8 8.1 3 .7 19 .6 3.0 1 .8 0.4 

19 20.7 5.7 22 .0 8.8 17 .4 4.4 6.8 0 .8 

20 7.1 4.1 18 .0 8.6 6.8* 2 .6* 3.2 0 .8 

21 9.3 3.8 17 .9 4.5 7.9 1 .1 14 .6 5 .8 

22 26.2* 5 .9* 43 1 .7 7.1 3.0 5.8 1 .4 

23 19 .1 10 .9 4.0 2.1 11 .0 4.6 4.3 1 .5 

24 10 .7 5 .7 11 .4 3.9 3 .9 1 .3 12 .9 3 .8 

25 10 .9 4.6 18 .7 2.6 7.4 1 .6 2 .5 0.3 

2 6 15 .9 5 .3 3 .1 0.6 1 .5 0.4 1 .5 0.2 

27 5 .6 3 .5 15 .5 5.1 1 .1 0.3 2.4 0.5 

28 21 .9 7.9 11 .6 4.1 0.8 0.2 2.8 0.3 

29 16 .4 7.7 1 .5 0 .4 2.0 0.1 

30 33.5 12 .5 1 .0 0 .2 3 .3 0.9 

31 17 .8 8.2 1 .5 0 .3 

# Hours 730 439 729 713 

Maximum 33 .5 22.0 19 .6 14.6 

Arith-Mean 5.8 4.1 1 .8 ~ I 1 .2 

46 
30 

R' 25 

20 

15 

c. 

Q 10 

5 

0 

30 

a. 

a' 25 

20 

15 

10 

5 

0 

30 

c,. 

a' 25 

20 

°~° 15 

10 

5 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Figure 17 . Dauphin Island 3-hour block average SOZ annual trends . 
00 

12 

a 

p" 10 

6 

c. 

4 

d 

0 

12 

a 

a" 10 

COD 8 

°D 6 

4 

0 

12 

a 

°" 10 

°° 6 

~. 

4 

00 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Figure 18 . Dauphin Island 24-hour block average SOz annual trends . 
35 

R. 

30 

O 25 

z 

20 eA 

15 

Q 10 

all 5 

^' 0 

35 

a 

a 30 

25 

z 

so 

~ 15 

10 

5 

0 

35 

a 

a 30 

N 

C) 25 

z Zo 

is 

Q io 

s 

o 

Begin Record 

1 31 61 

R 

R 

A 

91 121 151 181 211 241 271 301 331 361 

Figure 19 . Dauphin Island 3-hour block average NOZ annual trends . 
v, 

0 

20 

a 

a 

16 

Z 12 

an 

iLl O 

~0 4 

0 

20 

a 

c+, 

S; 16 

V 

Z 12 

an 

6 

d 4 

0 

20 

c4 

c+, 

16 

O 

12 

on 

c, g 

d 

00 4 

'" 0 

1 

Begin Record 

r 

ca 

.y 

!. 

A k( b 

31 61 91 121 151 181 211 241 271 301 331 361 

Figure 20 . Dauphin Island 24-hour block average NOZ annual trends . 
3

. 

s Z . 

1- 

Z 

s 

h 

0 

4 

3 -

V 

r 

o~ 2 - 

0 

~ 

4 

3 

olo 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

60 

1 

moo 

% 

% 

''Ililliiiiiiiillllliilljll 

11111 

==moo=" 1111 

00 '0 

40 

i 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

' 

__ 

1111111 i 

'I = 10 41%b 

' `~' 

do 

4% 

"iiijlllli , % 

.0 40 4% do 

~, 

400 

r ` 00 

Hour CST 

Figure 21 . Dauphin Island diurnal SOz variations as represented by first (dashed), 

second (solid), and third (dashed) quartile lines . 

51 
12 

10 

6 

C~ 4 

a 2 

0 -

10 

6 

H 

V 

0 -

7 

6 

5 

4 

3 

O 

z 

0 

S 

N 

O 

Q` 5 

4 

3 

U 

1 A 

1 

ago go do *a 

do go 

.. " ~ " 4m r 

Cc :31 

i~~ 

/ rte`' `' 

V 

k3- . 

' ``~'+ `~' 

ao 

., 

.00, 

r 

do ~4ft,06 ~ftb 

60 '00~

" 

' 

/ 

.00 r~ft, 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 21 continued . 

52 
5- 

N 

O 

00 

3-

2 

1 

6 

5' 

00 4-

3 

i. 

j 

3 

00 

ON 

1 

3 

U~ 2 

00 

ON 

ON 

1 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

'`~*4 I-%,0 ' % ~rl~~ 

~~i~` ~ 

10 

~i~ 

do do 

do ft& mo oft v 

r 

I 

1000 111,11,11111111111111Illjllllllllllllllllll111111111111 

00 

do 'Op 

ap Oft 

4kb 

4w. I do 

000 

t 

/~ 

/ / 

i ~ ~ 

- - - - - - /"~~ ~ ~~ 

~ 

64 % / 

dl% "r .0- doo 

_r 

i~ J* 

doo -% 410 

Hour CST 

Figure 21 continued . 

53 
6' 

5' 

4~ 

3 

2- 

1, 

6 

5 s4 

3 

1 

10 

9 

V 

z 

6 

5 

y 3 

2 

1 

S 

7 

z 6 

s 

4 

3 

an 

1 

/doo 

~ 

/dw 

ft& 00 

.0 *ft .0 

OP 

'0 

~ ..~~ ~ `" 

- '~--~ - - - - - - - - - - - - - - - 

do dm 

oft 

40 am 

~ 

oft ` "ft .. 

610 Oft 

' 

doo 

4m ~ 

r 

/100 

'I ` `~ 

' 

411h do 4- 

ftb 

.00 am 

\r J* oft ' 

r / 

_ 

1 1 1 I I I I I I- 1 --I-- T 

A0 

40 dw 

r go 

` ~`` '~ 

i 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 22 . Dauphin Island diurnal NOz trends as represented by first (dashed), second 

(solid), and third (dashed) quartile lines. 

54 
9 

V 

z, 

6 

~ . 5 

4 

3 

1 

14 

12 

z io 

g 

c, 6 

O 4 

U 

0 

0 

12 

z io 

g 

6 

O 

z 

Z 

14 

12 

10 

~. 

6 

A 

2 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

i 

I ~ ~` go 

~ 

Oft 

I 

~ 

i 

i~I 4%. 40 do 

ills No 

dab 4.b 

oft 

J* 10 

aim 

do oft ap do '60 .0 

' do 

'''I'M 

+ 

* 

111,11111111111110000444~~ 

do 

do ftb do 

stir 

i-- I I I 1 1 

`~ do **#4. ..'00 ~ 

I 40 

~ / ~~/ 

`` ' 

i 

dill 

Hour CST 

Figure 22 continued. 

55 
10~ 

9' 

g . 

00 

6~ 

5' 

4~ 

3 

2 . 

8 

V 

Z 6' 

5-

4 

3' 

0 . 

5 

~ a -

z 

3 " 

iU. 

00- 1 

0 . 

5 

z 

00 3 

2 . 

R. 

0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

/' % ~ / 

aft 40 do 

11% do 

00 

r~~-' `` I+~~rr~~ 

' ``` '' `` `~ ~ / 

"0 

~~ ~ ~~r~ ~~ 40 am ~r/ 

. . . . 

i 

40 40 / 

1 

do 

dow an r 

i 

_ , ' 

' ~`- 

Figure 22 continued. 

56 
Using the combined air quality / meteorology data sets, monthly wind and pollution roses 

were created as shown in Figs . 23 - 34. The pollution roses represent the range of concentrations 

associated with a particular direction (i .e ., direction from which the wind is blowing). Note that the 

February 1998 N02 rose is only 65% complete, due to failure of the NO, monitor. S02 maximums 

are mostly associated with northerly wind directions ; N02 maximums also occur mostly with 

northerly winds, however higher concentrations from the west and southwest are occasionally seen . 

This directional dependence is clear in Tables 21 and 22, which list the monthly 1, 3, and 24 hour 

block-averaged maximums for SOz and NO2, respectively . N02/ NOX ratios are included in Table 

22 . In general, the ratios are high, indicating a more aged air mass (and more distant source). For 

comparison to the National Ambient Air Quality Standard established by the U.S . EPA for SOZ (see 

Table 23), the maximum 3 hour S02 concentration was 29.2 ppb and for 24 hours, 10 .2 ppb . 

The entire hourly air quality record for SOZ and NOZ obtained during this study period was 

ranked by concentration, and the top 10% selected for the analysis listed in Table 24 . The greater 

frequency of high concentration measurements during the months of September to January is seen; 

even more striking is the clear association of high concentrations with north-northeasterly winds for 

both pollutants . Therefore, from this analysis it may be concluded that ambient air quality 

experienced at Dauphin Island is mostly dominated by land-based conditions, with little influence 

from offshore sources . 

57 
Table 21 . 

Dauphin Island SOZ Maximums (ppb) 

Month Averaging Interval Maximum Day / Hour Wind Direction / Speed 

May 1997 1 hour 16.3 16/03 035/5.3 

3 hour 11 .5 

9 .1 

13/14 

16/05 

114/2.4 

048/4.8 

24 hour 4.6 

June 1997 1 hour 11 .1 2/23 342/7.6 

3 hour 7 .4 4/11 008/4.1 

24 hour 4.7 

July 1997 1 hour 42.5 4/0 322/3.8 

3 hour 20.2 4/02 317/3.1 

24 hour 8.6 

August 1997 1 hour 13 .5 7/06 006/4.5 

3 hour 11 .7 7/08 012/4.1 

24 hour 6.6 

September 1997 1 hour 38 .0 13/12 035/ 1 .2 

3 hour 23 .0 30/08 278/4.7 

24 hour 7 .8 

October 1997 1 hour 37 .1 19/09 355/6.4 

3 hour 29 .2 19/11 360/5.9 

24 hour 9 .9 

November 1997 1 hour 29.3 23/ 13 003/7.7 

3 hour 25 .6 23/ 14 003/7 .9 

24 hour 8 .8 

December 1997 1 hour 50.5 5/06 326/9.5 

3 hour 20.2 5108 331 /9 .2 

24 hour 10.2 

58 
Table 21 continued. 

Month Averaging Interval Maximum Day / Hour Wind Direction / Speed 

January 1998 1 hour 22.4 30/ 14 005/2.8 

3 hour 13 .6 30/ 17 332/ 1 .0 

24 hour 6.1 

February 1998 1 hour 23 .0 21105 041 /5 .3 

3 hour 13 .2 8/08 330/3.8 

24 hour 6.3 

March 1998 1 hour 17.0 13/04 054/6.6 

3 hour 11 .4 13/ 11 043/3.8 

24 hour 6.5 

April 1998 1 hour 13 .7 1105 357/8.9 

3 hour 9.8 6/08 039/4.4 

24 hour 4.3 

59 
Table 22. 

Dauphin Island NOZ Maximums (ppb) 

Month Avg. Int. Maximum Day / Hour Wind Dir. / Speed NOZ / NO, 

May 1997 1 hour 22.1 6/05 239/ 1 .6 0.73 

3 hour 11 .2 16/02 019/4.4 0.98 

24 hour 5 .7 

June 1997 1 hour 17.9 23/09 349/4.3 0.85 

3 hour 12.6 4/08 003/4.3 0.88 

24 hour 7.5 

July 1997 1 hour 27.4 11/08 003/3.3 0.88 

3 hour 18.5 11/08 008/3.1 0.90 

24 hour 8.6 

August 1997 1 hour 19.0 29/02 295/ 1 .8 1 .00 

3 hour 12.6 7/05 353/4.0 1 .00 

24 hour 7 .9 

September 1997 1 hour 22 .4 13/06 011/4.9 0 .97 

3 hour 15 .5 8/08 01115.0 0 .90 

24 hour 7 .1 

October 1997 1 hour 28 .0 29/ 17 298/0.8 0 .91 

3 hour 23 .8 20/08 356/3.2 0.78 

24 hour 14.9 

November 1997 1 hour 28 .7 

26.4 

24/20 

18/01 

000/0 

030/4.7 

1 .00 

0.82 

3 hour 18 .4 23/ 14 003/7.9 0.66 

24 hour 10.3 

December 1997 1 hour 51 .4 18/21 178/3 .1 0.78 

3 hour 29.1 16/05 352/3.9 0.80 

24 hour 16.8 

60 
Table 22 continued. 

Month Avg. Int. Maximum Day / Hour Wind Dir. / Speed NOz /NO, 

January 1998 1 hour 33 .5 30/ 19 Missing 0.79 

3 hour 22.5 30/20 Missing 0.92 

24 hour 12.5 

February 1998 1 hour 22.0 19/06 282/1 .6 0.96 

3 hour 13 .6 20/08 288/4.4 0.83 

24 hour 8.8 

March 1998 1 hour 19.6 18/22 013/4.5 1 .00 

3 hour 12.6 18/23 002/4.3 1 .00 

24 hour 5.0 

April 1998 1 hour 14.6 21/07 003/5.6 0.80 

3 hour 12.7 21 /08 004/5.2 0 .83 

24 hour 5 .8 

Table 23 . 

U.S . Federal Primary and Secondary Ambient Air Quality Standard 

Source: 40 CFR § 50, July 1992 

(From Bouble et al ., 1994) 

Type of Averaging Frequency Concentration 

Pollutant Standard Time Parameter [tg / m3 ppb 

Sulfur Oxides (as Primary 24 hour Annual 365 138.7 

sulfur dioxide) Maximum 

1 year Arithmetic 80 30.4 

Mean 

Secondary 3 hour Annual 1300 494 

Maximum' 

Nitrogen Dioxide Primary and 1 year Arithmetic 100 53 

Secondary Mean 

`Not to be exceeded more than once per year. 

61 
Table 24. 

Frequency Distribution of Dauphin Island Top 10% Concentrations 

Month NOZ (827 samples) SOz (842 samples) 

May 1997 18 20 

June 1997 18 14 

July 1997 69 58 

August 1997 45 64 

September 1997 42 103 

October 1997 169 156 

November 1997 95 106 

December 1997 197 138 

January 1998 108 58 

February 1998 43 65 

March 1998 11 30 

April 1998 12 30 

Direction 

0-45 246 296 

46-90 75 103 

91 - 135 16 24 

136- 180 16 36 

181 -225 21 34 

226-270 75 32 

271 -315 104 65 

316-360 255 239 

Missing 19 13 

62 
Dauphin Island 

May 1-May 31 ; Midnight-11 PM 

% ~g$ `iox 1~ :x 

ux 

l l / / ~'x ~I% 

\ \ ~ ~ ~ ~ 1 

s 

CALM WINDS 0.14% WIND SPEED (KNOTS) 

NOM: Frrquemia 11-16 1721 +11 

LNfmte dmrlon 1-3 1-6 

Jlom wi~idl Ne G1(.45 

mm u Dbxina. 

I l l / / x\ 41 \ex \ax `pox ~~rs ins 

I I I I / 

\ \ \ / ~ ~ / 

s 

Zero Cone. 0.55% Concentration ppb 

Al0 11-I6 0-11 +Sf 

Figure 23 . Dauphin Island May 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 

bottom right) . 

63 

s 

Zero Cone. 49 .36% Concentration ppb 

7.10 11-I6 17.31 t7l 
Dauphin /stand 

June 1-June 30; Midnight-11 PM 

N 

4s \ ex \ ax 

`iax `ux 

ux 

I I / I I ~ E 

- - 

i 

i 

s 

CALM WINDS 0.70% WIND SPEED (KNOTS) 

NOlE:Frrquercic _ 7-10 1116 01721- 11l 

i~'taeArrtuon 

/mm Mud rlu G(~IIS 

wiM v bWwinF. 

i 

\ ~s \ ex \ as \ iox 

~iex us 

E W I I I ' / x I I ~ E 

I 

S 

Zero Cone. 0.14% Concentration ppb 

7-1o a-,e 17 ~1 .21 

Figure 24. Dauphin Island June 1997 wind (top) and pollution roses (SOz bottom left, NOz 

bottom right) . 

64 

S 

Zero Conc. 53.21% Concentration ppb 

~ 7d0 II-I6 I731 
Dauphin !stand 

July 1-July 31 ; Midnight-11 PM 

I 

~ - - ~ \ 

liox 

ax 

I% I% 

S 

CALM WINDS 1.85% WIND SPEED (KNOTS) 

N07E: Frequekin y~0 (ldb 1721 ' 

iMiaweeimeon /-3 1-6 

/min wV~iM rIU LU.NS 

wirdu Dlowind. 

N 

_ \ \ 

16R 

I 

E 

I 

W I 

\ ~ ~ ax ~ 

iox 

i :x 

I.A I b" 

I I I 

S S 

Zero Cone. 30.07% Concentration ppb Zero Conc. 0.00% Concentration ppb 

1721 .2 '_3 .p It-16

~ 

7' 46 7_IO L.I6 17.I/ NI 3 

Figure 25. Dauphin Island July 1997 wind (top) and pollution roses (SOZ bottom left, NOz 

bottom right) . 

65 
Dauphin Island 

August ]-August 31; Midnight-I] PM 

N 

i 

I 

I 

I'ox ax 

E 

S 

CALM 5/ADS 0.813'o WIND SPEED (KNOTS) 

NOTE: fmi- ~~ IF16 I7-Z7 +Il 

iMicve d'mrlon 

i-,_7 

A.. - - l.'ALNS 

.IM is Dbwins . N 

i 

/ ~ - - 

/ ~ ~ 1as ~ias 12% 6x 

S 

Zero Cone. 36.48% Concentration ppb 

lIJ6 1L1/ t31 

Figure 26. Dauphin Island August 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 

bottom right). 

66 

\ ~ . - - 

Zero Cone. 3.52Y Concentration ppb 

110 11 11 17.71 X71 

IJ 
Dauphin Island 

September 1-September 30; Midnight-11 PM 

N 

i 

i 

1 

~Bx ~ios i:tc 

i 

i 

s 

CALM WINDS 1 .12 % W/ND SPEED (KNOTS) 

Ind'mt

: 

adinno~ IJ I-6 7-10 lld6 17-31 all 

m wNd eYr CAfAIS 

kiMu bbw'na. 

l / ~ ~ 6; ~ 

ax `~os ~ 

i :x 

ux 

x I.x I I I I 

I I 1 I ~ I 

\ ~ ~ \ 

W 

i 

l. ; ~Is ~e~ ~ox 

~i7x 

I I / I I I 

I 

i 

i 

E 

S S 

Zero Cone. 7.51% Concentration ppb Zero Cone. 0.00% Concentration ppb 

~ 7-10 L-(6 17.11 +31 .3 16 110 11d6 17-11 a31 

Figure 27 . Dauphin Island September 1997 wind (top) and pollution roses (SOZ bottom left, 

NOZ bottom right) . 

67 
Dauphin Island 

October 1-October 31 ; Midnight-!I PM 

N 

k 

12% 

16% 

4% 

20% 

E 

S 

CALM WINDS 0.00% WIND SPEED (KNOTS) 

107E:Frcqum<ia x.70 II-16 17-21 t11 

iMf~,vrNrrciion !-3 

/mm w/tiM Us GlLS 

wirW u Dbuind . N 

i 

i 

- ~ \ \ 

I l ~ / \1111 

116 

ax .x 

W 

I i I 

\ / I 

\ \ _ 

10% 

E W 

I / / 176 

:s 

I 

\ _ - - / 

SO% 

E 

S S 

Zero Conc.16.449b Concentration ppb Zero Conc. 0.00% Concentration ppb 

, ~ 7- Il-l6 1~21 .21 

13 F6 L/0 Il-l6 17.31 +21 

Figure 28. Dauphin Island October 1997 wind (top) and pollution roses (SOz bottom left, NOz 

bottom right) . 

68 
Dauphin /stand 

November 1-November 30: Midnight-]1 PM 

N 

1 iox 

I 

I 

I 

- ' \ _ - 

S 

CALM WINDS 0.86%a WIND SPEED (KNOTS) 

F--. 1721 

1-10 

\\ 12. 

14~ 112% 

4~ 

E 

E 

I ~ l `ias 1 i :s 

ins 

- ' i 

i 

S S 

Zero Cone. 8.86% Concentration ppb Zero Cone. 0.31% Concentration ppb 

7-10 ll-I6 0-31 i11 y 7-IO IIJ6 D-1I s1I ~_~ 41 

Figure 29 . Dauphin Island November 1997 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

69 
Dauphin /stand 

December I-December 31; Midnight-ll PM 

- _ \ 

/ \ ~ \ \ \ 

/ / /~ ~ \ \ \ 

x 

~ ux ~ ux 

isx 

I l Ins sx \ ax \ ios 

E 

\ ~ - - 

S 

CALM W/NDS 0.67% WIND SPEED (KNOTS) 

NOTE: ircq~a 

~ J-10 11-16 17-11 s3i 

iMimuMrnrion 

/rolnwIYAtlu ('A(JIIS 

wiM u 6bwiry. N 

- - 

~ ~ \ \ \ 

/~ ~ ~ \ \ \ \ 

~ 

\as\~os~us 

Ins is 

I ~ I ~ ~ ~ i I I 

- - 

/ ~ ~ \ \ \ 

~ ~ 

\ iox`us 

~~~s 

\ I I ex 

as 

~ 

~x I ~ ~ i I I 

I I 

\ ~ \ \ \ ~ - ~ / / / 

- i 

- - ~ , / 

S S 

Zero Cone. l0.49% Concentration ppb Zero Cone. 0.14% Concentration ppb 

710 11-16 031 .71 

1_3 

" ~.~p 11-16 17.31 a2l 

Figure 30. Dauphin Island December 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 

bottom right) . 

70 
Dauphin Island 

January 1-January 31 ; Midnight-11 PM 

/ / / ~ \ \ \ 

1 /6R 

I14 

A

8R 

4% 

I i 

zo% 

E 

s 

CALM WADS 0.56% WIND SPEED (KNOTS) 

NOTE: Frcquemu _~p Ild6 IZII a1f 

i~mred'mrion 

,,_7 

~.hiM ~1r GIfXS -/rwn 

w1M u Obwi". 

N 

i 

/ ~ / ~ ~ \ ~ \ \ \ 

4s s~ 

ei\~as`i :xlux 

iex 

I ~ ~ 1 ` ~ ~ E 

i 

i ~ - - 

/ / 

A

sx 

'ixx 

~,x e . 

I 

\ - - 

:os 

e 

S S 

Zero Cone. 9.59 Concentration ppb Zero Conc. 0.00% Concentration ppb 

~y -!0 lld6 1731 '71 

1.3 - 

7/0 II-I6 17-II X71 

ld 

Figure 31 . Dauphin Island January 1998 wind (top) and pollution roses (SOz bottom left, NOz 

bottom right) . 

71 
Dauphin Island 

February 1-February 28; Midnight-I1 PM 

- - 

\ ~ \ 

/ / / \ \ \ \ \ 

l % ~,~ \ sw \ as \ iox 1 its ins 

I 

- - ~ i 

S 

CALM WINDS 0.45%a WIND SPEED (KNOTS) 

NOTE: Frequmdo ~_~p 11-16 17-17 t71 

i~ratrJirtmon /-3 I-6 

/m/n ~Milh Ui! (.

.1L4IS 

mm u Ebxiy. N 

\ \ \ \ \ 

Isx 

us 

/ / ~~ .x \ \ ax 

`ws 1 ux 

I 

I 

i 

~ - - ~ \ 

\ ~ \ 

\ \ \ 

/ ~ ~sx liox 12 . 

I I / .~ 6x 

i 

-- , ~ 

- - i / 

s s 

Zero Cone. 7.86% Concentration ppb Zero Cone. 9.45% Concentration ppb 

~ 7-IO 11 .16 77-3! X71 ~ 7.1Q 11-16 17.11 X11 

i 

Figure 32 . Dauphin Island February 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

72 
Dauphin Island 

March 1-March 31 ; Midnight-11 PM 

i ~ - 

\ 

\ 

N J211 

as I I I .x I i I E 

I 1 

\ - - - / 

S 

CALM W/NDS 0.56% W/ND SPEED (KNOTS) 

N07E:Frtpueda _ 7-0,0 11-I6 1737 +31 

i~mndrsaw 

Jmn ».4A, Mr 

r-4 

wirN u Dbwind . N 

I

\

~ 

\ \ \ / 

l / x~ ~I R ~ei ~iox 1us 14x 

I I I I ~ E W I 

u I 1 

\ ~ ~ ~ \ a ~ l I 

L 

E 

S S 

Zero Cone. 19 .03% Concentration ppb Zero Cone. 36 .36% Concentration ppb 

13 F6 710 L.Ib 0.31 +3( I_~ 7.10 11-16 0-11 X11 

Figure 33 . Dauphin Island March 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

73 

\ - - / 
Dauphin Island 

April 1-April 30; Midnight-11 PM 

W 

i 

- - \ 

ux l

II

iex 

ax 

I I,% I i 

1 \ 

\ \ ~ 

\ \ ~ - - 

zo% 

E 

S 

CALM W/NDS 0.15% WIND SPEED (KNOTS) 

/ NOTE: PrrqYmda ~ 710 1116 0-31 

d'rtttion .i~tvle rom .,urn de ~wrws ~~ 

M.e is el-q . N 

I1 2~ 

16 

S S 

E 

Zero Conc. 25 .04% Concentration ppb Zero Conc. 50.74% Concentration ppb 

y A10 11-16 17'-- 

'3 ~ 

7.10 11 -l6 17.31 X71 

Id 

Figure 34. Dauphin Island April 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

74 
B . Breton Island Air Quality 

Wind measurements obtained on Breton Island by the RM Young Wind Monitor were 

merged with the hourly-averaged air quality data except for during the periods of 3 - 10 June, 1997 

and 24 June to 11 July 1997; for these times winds were computed from the RM Young Gill UVW 

Anemometer. Monthly time series are presented in Figs. 35 - 48. Hourly SOz concentrations are 

generally within 2 - 3 ppb, while NOz mostly falls within 6 ppb. One notable feature is the greater 

frequency of short duration (hours to a day) high NOZ concentration events, often reaching peaks 

in excess of 40 ppb . 

Although the station monitoring was extended through July 1998, logistical concerns allowed 

only one servicing trip after 21 April 1998 . As can be seen in Figs. 47 and 48, little variation is 

present in the SOZ record while a slight positive drift may have entered the NOZ (NOX) data. 

Because an acceptable calibration was achieved at station removal, the data is presented here . 

However, for analysis purposes, the periods of May 1997 - April 1998 and June 1997 - May 1998 

are selected for SOz and NOZ annual statistics since they are most complete for the parameters . 

The annual arithmetic mean SOZ concentration found at Breton Island is 1 .2 ppb with a 95% 

confidence level of 0.034 (based on 6863 samples, 78.3% complete) . The annual arithmetic mean 

NOZ concentration is 6.2 ppb with a 95% confidence level of 0 .154 (based on 7096 samples, 81% 

complete) . While the annual SOz statistics are in good agreement with previous findings listed in 

the Interim Report, the annual NOZ is about 1 ppb higher . This may be accounted for primarily by 

the relocation of the monitor to ground level, and to a lesser extent by the use of computed NOz 

values . 

Frequency distribution of the air quality data is depicted in Fig. 49. Approximately 80% of 

the SOZ record is less than 2 ppb . NOz concentrations are below 5 ppb almost 60% of the record . 

On the other hand, higher concentrations are observed more frequently here than at Dauphin, with 

concentrations greater than 20 ppb recorded almost 5% of the time. 

Breton Island monthly maximum and average SOZ and NOZ concentrations are listed in 

Tables 25 and 26, respectively . Slight peaks of both pollutants during the late fall - early winter 

months are evident here as at Dauphin. Note that the higher NOz averages at the end of the record 

may reflect the positive offset in the monitor. These seasonal trends are illustrated in Figs. 50 - 53, 

which show the annual 3- and 24-hour average trends . The improvement in data capture following 

relocation of the equipment is clear in these figures . 

Diurnal quartile values are shown in Figs. 54 and 55 for SOz and NOD respectively. Median 

SOz is generally less than 1 ppb; a very slight increase is sometimes seen in late morning to midday 

hours. Median NOZ values are higher at about 3 - 6 ppb. The morning peak observed at Dauphin 

Island is much less pronounced here, and often accompanied by an evening increase . 

75 
360 

315 

a 270 

225 

180 

135 

90 

45 

0 

12 

10 

8 

a 

a 

6 

Z q 

2 

0 

r 

. . . w ~. r 

u 

Cal 

I 

I 

I 

I 

i 

I 

.~ 

A 

I A. AL L d, Ln 

on 

. .. 

NOD Monitor Offline 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - May 1997 

6 

5 

4 ,a 

a 

3 p" 

2 

1 

0 

Figure 35 . May 1997 time series of Breton Island hourly-averaged concentrations and wind direction. 
360 

315 

,0 270 

225 

~. 

180 

135 

90 

45 

0 3 

2 

a 

a 

J 

20 

18 

16 

14 

12 

10 

O 

6 

4 

2 

0 

1 

Figure 36 . June 1997 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - June 1997 
__l 00 

360 

315 

,0 270 

225 

~. 

q 180 

135 

90 

45 

0 

24 

21 

.r 18 

a 15 

S' 12 

z 

6 

3 

0 

Figure 37. 

T 

-w 

Cal ~ Offline 

1 

1 

1 

Station Offline 

Through August Due to 

Hurricane Danny 

I 

I 

I and 

1 

I Relocation of Monitoring Equipment 

1 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - July 1997 

7 

6 

s 

a 4 

a 

3 

2 

1 

July 1997 time series of Breton Island hourly-averaged concentrations and wind direction. Missing SOZ 

and NO, on 11 and 12 July. 
v 110 

360 

315 

0 270 

225 

180 " 

135 

90 

45 

0' 

44 

40 

36 

32 

a 28 

c~. 24 s Zo 

16 

12 

8 

4 

r 

r 

Cal 

AA 41 

A 

an 

~ 1 j.W ~~~ L Y ~ I ILL 

12 

10 

a 

-6 

'4 

_2 

-0 

0 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - September 1997 

Figure 38. September 1997 time series of Breton Island hourly-averaged concentrations and wind direction. 
360 

315 

C 

a 270 

225 

c. 

180 

135 

90 

45 

0 18 

15 

12 

9 R" 

6 

3 00 0 

55 

50 

45 

40 

35 

F+. 30 

" C 25 

z so 

is 

io 

s 

0 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - October 1997 

0 

Figure 39. October 1997 times series of Breton Island hourly-averaged concentrations and wind direction. SOZ and 

NO, missing on 26 October. 
00 

360 

315 

,0 270 

225 

~. 

180 

135 

3 90 

45 

0 

44 

40 

36 

32 

a 28 

p" 24 

S' 20 

16 

12 

8 

4 

0 

14 

12 

10 

a 

6 

4 

2 

0 

Figure 40. November 1997 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - November 1997 
360 

315 

0 270 

225 

~. 

180 

135 

90 

45 

0 12 

10 

00 

N 

50 

45 

40 

35 

30 

r, 25 

O 20 

15 

10 

5 

0 

8 

6 R" 

4 

2 

Figure 41 . December 1997 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - December 1997 
00 

w 

360 

315 

,0 270 

225 

c. 

180 

135 

3 90 

45 

0 

44 

40 

36 

32 

28 

R. 24 

20 

16 

12 

8 

4 

0 

Breton Island - January 1998 

8 

7 

6 

5 c+. 

4 Q" 

3 

2 

1 

0 

Figure 42. January 1998 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
00 

360 

315 

,0 270 

225 

c. 

q 180 

135 

90 

45 

0 

39 

36 

33 

30 

27 

p, 24 

21 

S' 18 

15 

12 

9 

6 

3 

0 

Breton Island - February 1998 

Figure 43 . 

11 

10 

9 

8 

7 a 

6 a 

5 

4 r~ 

3 

2 

1 

0 

February 1998 time series of Breton Island hourly-averaged concentrations and wind direction. Missing 

air quality data on days 20 - 22, 23 - 25, 26 - 27, and 28 . 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 
360 

315 

A ,0 270 

225 

180 

135 

3 90 

45 

0 

00 

25 

20 

a 15 

z 10 

5 

0 

Figure 44. 

11 

10 

9 

8 

7 ^a 

6 a 

5 

4 r~ 

3 

2 

1 

0 

March 1998 time series of Breton Island hourly-averaged concentrations and wind direction. SOZ data 

has been corrected for an offset . 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - March 1998 
360 

315 

,0 270 

y 225 

~. 

180 

135 

3 90 

45 

0 6 

5 

4 

a 

3 a 

2 

63 

56 

49 

.a 42 

a 

a 35 

O 28 

z 21 

14 

7 

0 

1 

0 

Figure 45 . April 1998 time series of Breton Island hourly-averaged concentrations and wind direction. SOz and NOx 

data missing on days 6 and 23 - 24 April . SOZ corrected for offset to 21 April . 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - April 1998 
00 

v 

360 

315 

0 270 

225 

~. 

180 

135 

90 

45 

0 

55 

50 

45 

40 

35 

a 30 

25 

z Zo 

is 

io 

s 

0 

Breton Island - May 1998 

8 

7 

6 

5 p, 

4 p" 

3 

2 

1 

0 

Figure 46 . May 1998 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
00 

360 

315 

0 270 

225 

180 

135 

90 -

45 

0' 

42 

36 

30 

a 

24 

18 

z 

12 

6 

Cal 

Missing Data 

Memory Overwrite 

1 

I 

" 2 

a 

1 

-0 

0 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - June 1998 

Figure 47. June 1998 time series of Breton Island hourly-averaged concentrations and wind direction. 
360 

315 

C 

0 270 

225 

~. 

180 

135 

90 

45 

0 2 

a 

1 p" 

00 

36 

32 

28 

24 

o. 20 

S' 16 

Z 12 

8 

4 

0 

0 

Figure 48 . July 1998 time series of Breton Island hourly-averaged concentrations and wind direction. 

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 

Breton Island - July 1998 
65 

60 

55 

50 

45 

0 40 

35 

~ 30 

~, 25 

20 

15 

10 

5 

0 

Breton Island SOZ ppb 

Based On Hourly Block Averages 

Period: May 1997 - April 1998 

15 

14 

13 

12 

11 

10 

o g 

v 8 

~ 6 

5 

4 

3 

2 

1 

0 

Figure 49 

0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8 .5 9.5 1 0.5 

Breton Island N02 ppb 

Based On Hourly Block Averages 

Period : June 1997 - May 1998 

>25 I 

0.5 2.5 4.5 6.5 8.5 10.5 12.5 14.5 16.5 18 .5 20.5 22.5 24.5 

Frequency distribution of Breton Island hourly-averaged pollutant concentrations 

recorded during this study period . 

90 
Table 25 . 

Breton Island SOZ Maximums and Averages (ppb) based on 1 Hour Block Averages* 

May 1997 June 1997 July 1997 September 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 2.0 0.7 1 .3 0.4 0.7 0.3 1 .1 0.6 

2 0.5 0.2 1 .6 0.7 6.0 1 .8 0.6 0.4 

3 0.2* 0.2* 1 .3* 0.6* 4.1 1 .2 2 .1 0.6 

4 0.5 0.5 2 .3 0.8 

5 0.5 0.3 1 .7 0.6 

6 0.6 0.3 0.6 0.4 

7 0.2 0.1 0.7 0.4 

8 0.5 0.1 2.3 0.8 

9 1 .0* 0.3* 1 .1 0.5 1 .3 1 .0 

10 5.6 2.4 0.6* 0.2* 39 1 .5 1 .1 0.9 

11 3.2 1 .1 0.8 0.5 1 .0* 0 .2* 4.6 1 .4 

12 1 .2 0.2 1 .1 0.5 0.3* 0.1* 2.5 1 .2 

13 2.6 0.8 1 .4 0.6 1 .6 0.6 

14 0.6 0.2 0.8 0.4 0.8 0.2 

15 1 .1 0.3 2.2 0.8 1 .5 0.5 

16 2.0 0.7 1 .2 0.5 1 .5 0.2 

17 1 .2 0.2 0.5 0.3 1 .2 0.7 

18 0.8 0.3 0.9 0.4 0.6 0 .3 

19 0.6 0.3 1 .3 0.6 1 .2* 0.5* 

20 1 .7 0.6 2.4 0.7 

21 0.7 0.1 2.0 0.7 

2 2 0.9 0.4 2.2 0.8 

23 1 .1 03 2.4 0.9 

24 0.5 0.2 1 .0 0 .5 0.2* 0.1* 

2 5 0.4 0.1 0.6 0 .1 0.4 0.3 

2 6 0.4 0.1 0.8 0 .2 5.0 1 .2 

27 0.5 0 .1 1 .5 0 .6 9.7 3 .8 

2 8 2.6 0 .3 1 .2 0.7 7.6 3 .0 

2 9 0 .2 0 .0 1 .5 0.6 10 .9 4.2 

3 0 0 .3 0 .1 0.5 0.3 7.0 2.8 

31 0 .4 0.1 

# Hours 593 542 257 599 

Maximum 5 .6 2 .4 6.0 10 .9 

Arith-Mean 0.4 0.5 J I 0.6 ' I 1 .1 

boxes indicate less than 75% (18 hours) complete. 

91 
Table 25 continued. 

October 1997 November 1997 December 1997 January 1998 

Day Max Avg Max Avg Max Avg Max Avg 

1 5.2 2.2 3.4 1 .0 3 .5 1 .2 3 .3 1 .5 

2 8.5 4 .5 3.8 1 .8 5 .3 1 .5 1 .1 0.8 

3 6.3 3 .4 5 .5 2.4 2.5 0.9 1 .4 0.7 

4 2.4 1 .2 2 .0 1 .1 1 .4 0.8 1 .1 0.6 

5 1 .9 0 .6 1 .7 0.9 3 .6 1 .3 1 .4 0.7 

6 0 .8 0 .2 2 .4 1 .2 6.1 1 .9 0.9 0.7 

7 0 .9 0.6 2 .8 1 .5 5.1 2.4 1 .1 0.8 

8 1 .4 0.6 8.1 4.4 1 .2 0.7 1 .8 0.9 

9 0 .1 0.0 6.1 3.7 1 .2 0.5 7.0 2.4 

10 0 .1 0.0 8.1 4.2 1 .6 0.7 5 .8 2.1 

11 0.6 0.1 8.4 3 .1 5.9 2.7 1 .3 0.9 

12 1 .1 0.6 1 .1 0 .4 6.4 3.7 1 .8 0.6 

13 1 .2 0.5 5 .1 1 .8 6.0 3.4 1 .7 0.8 

14 3 .2 0.7 4.7 2 .0 4.8 2.1 0.8 0.6 

15 5 .2 3 .3 4.8 1 .3 11 .0 4.9 2.5 0 .9 

16 16 .8 5 .7 3.8 1 .6 5.3 2.6 7.1 3 .3 

17 13 .4 6.0 5.7 2 .6 5 .4 1 .7 3.7 1 .7 

18 7.6 4.3 2.5 1 .6 7 .2 1 .9 2.5 1 .3 

19 7.4 3.1 5.2 1 .5 2 .6 0.7 3.1 1 .6 

2 0 9.4 3.1 1 .3 0.7 1 .1 0.7 4.9 1 .9 

21 8.1 4.3 1 .6 0.9 1 .3 0.9 1 .2 0.9 

22 10.5 2.9 11 .8 1 .2 3 .9 1 .4 0.8 0.6 

23 3 .4 1 .4 8.8 4.2 2 .3 1 .1 2.0 1 .1 

24 1 .1 0.6 5.9 1 .9 2 .4 1 .2 3.5 1 .5 

25 1 .1 0.4 2.5 1 .2 9.1 2.3 4.3 2.0 

26 1 .3* 0.4* 1 .7 0.5 9.2 2.7 1 .1 0.9 

2 7 3.9 1 .3 1 .7 0.5 1 .6 0.9 3.9 1 .4 

2 8 6.5 2 .9 0 .9 0.3 5 .4 1 .8 5 .1 4.1 

29 6.8 2 .4 0 .7 0.2 2.4 1 .5 2.8 2.0 

3 0 3 .1 1 .4 4 .1 1 .9 5.2 2.6 3 .6 2.3 

31 1 .4 0.7 4.1 2.0 3 .6 2.3 

# Hours 736 713 740 738 

Maximum 16 .8 11 .8 11 .0 7.1 

Arith-Mean 1 .9 1 .7 1 .8 1 .4 

boxes indicate less than 75% (18 hours) complete. 

92 
Table 25 continued. 

February 1998 March 1998 April 1998 May 1998 

Day Max Avg Max Avg Max Avg Max Avg 

1 2.1 0.9 1 .0 0.7 5 .3 0.7 3.3 1 .3 

2 1 .8 0.9 2.1 0.9 1 .1 0.4 1 .3 0.9 

3 1 .9 0.9 9.0 1 .5 1 .2 0.3 1 .5 0.9 

4 4.7 2.7 2.0 1 .0 3 .9 0.8 2.9 1 .6 

5 3.2 1 .9 0.2 0.0 5 .0 2 .3 2.2 1 .4 

6 7.2 2.1 0.0 0.0 3 .6 1 .9 3.0 1 .7 

7 6.9 3 .2 0.2 0.1 0.5 0.2 1 .6 0.8 

8 9.6 4.5 1 .6 0.4 0.3 0A 1 .1 0 .6 

9 5.0 1 .9 2.5 1 .1 3 .7 1 .4 1 .1 0.8 

10 0.8 0.2 1 .0 0.6 3 .3 0.4 1 .9 0.9 

11 1 .2 0.6 3 .7 1 .5 3 .1 1 .4 7.3 3 .3 

12 4.8 2.0 6.1 2.9 2 .0 1 .2 3.1 2 .0 

13 4.6 2.1 4.4 2.1 0.8 0.2 2.6 1 .7 

14 6.2 2.6 1 .2 0.6 1 .1 0.2 2.0 13 

15 1 .4 0.7 1 .3 0.4 0.3 0.1 6.2 1 .5 

16 0.7 0.2 1 .3 0.3 0.1 0.0 7.4 1 .8 

17 1 .0 0.3 0.3 0.0 1 .4 0.4 4.9 2 .3 

18 2.9 1 .6 0.1 0.0 1 .2 0.2 7.7 3 .4 

19 3.1 1 .0 0.2 0.0 4.1 0.9 7.7 3 .9 

2 0 4.7 2.5 4.5 1 .7 4.6 2.4 4.9 2 .6 

21 2.9 0.5 4.9 2.2 2.1 1 .4 

22 1 .9* 1 .0* 2.4 1 .2 3 .0 1 .1 2.3 1 .3 

23 2.7 1 .7 9.8 2.9 0.9 0.9 2.3 1 .2 

24 2.9 0.6 3 .1 2.6 2.9 1 .7 

25 0.7* 0.2* 1 .2 0.3 3 .6 1 .9 2.2 1 .4 

26 0.5 0.1 1 .0 0.4 1 .7 1 .2 2.1 1 .3 

27 0.8 0 .2 2.0 1 .0 2.1 1 .2 

28 0.8* 0.7* 0.9 0 .2 1 .1 0.7 1 .9 1 .0 

29 1 .0 0 .2 1 .1 0.7 1 .4 0.9 

3 0 2.3 0 .2 1 .4 0.8 1 .0 0.7 

31 0.4 0 .1 0.7 0.6 

# Hours 532 739 674 744 

Maximum 9.6 9.8 5.3 7.7 

Arith-Mean I 1 .5 0.9 0.9 1 .5 

boxes indicate less than 75% (18 hours) complete. 

93 
Table 25 continued. 

June 1998 July 1998 

Day Max Avg Max Avg 

1 0.6* 0.4* 0.7 0.7 

2 1 .4 0.8 

3 1 .2 0.9 

4 1 .1 0.8 

5 1 .2 0.7 

6 1 .7 0.9 

7 1 .1 0.7 

8 1 .1 0.8 

9 1 .1 1 .0 

10 0.8 0.7 

11 0.9 0.7 

12 0.8 0.7 

13 1 .1 0.8 

14 0.7* 0.6* 1 .1 0.9 

15 0 .7 0.6 0J 0.7 

16 0.7 0.6 0J 0.7 

1 7 1 .2 0.9 0.7 0.7 

18 1 .2 0.8 0.7 0.7 

1 9 0.9 0.6 1 .0 0.7 

2 0 1 .1 0.7 1 .1 0.8 

21 1 .0 0.7 1 .1 0.9 

22 0.9 0.6 1 .2 1 .0 

23 1 .0 0 .7 0.7 0.7 

24 0.9 0 .7 1 .0 0J 

2 5 1 .1 0 .8 1 .0 0.7 

2 6 1 .1 0 .7 0.9 0.7 

27 1 .2 0 .9 1 .1 0.8 

28 1 .1 0.8 1 .1* 1 .0* 

29 1 .1 0.8 

30 0.7 0.7 

31 

# Hours 409 657 

Maximum 1 .2 1 .7 

Arith-Mean I I 0.7 I I 0 .8 

boxes indicate less than 75% (18 hours) complete. 

94 
Table 26. 

Breton Island NOZ Maximums and Averages (ppb) based on 1 Hour Block Averages` 

May 1997 June 1997 July 1997 September 1997 

Day Max Avg Max Avg Max Avg Max Avg 

1 9.3 5 .8 7 .4 3.7 17 .8 3.1 

2 9.1 3 .3 13 .1 5.6 9.0 2.0 

3 10 .3* 7.0* 17 .7 7.0 7.7 4.0 

4 10 .1 4.8 5 .0 3 .2 

5 13 .2 6.0 4.0 1 .5 

6 18 .1 6.8 20.3 2.7 

7 7 .3 3.7 18 .2 2.6 

8 11 .3 5.4 40 .0 8.3 

9 25.0 5.5 14 .1 6.8 

10 2 .1* 1 .3* 18 .9 10 .3 5.9 3.6 

11 6.4 2.5 19.2* 5 .4* 10 .0 3.3 

12 13 .4 6.6 11 .2* 4.6* 8.9 3.1 

13 14 .8 5.5 22.4 5.5 26 .3 6.3 

14 8.4 3.9 13 .6 4.3 13 .0 4 .1 

15 10.2 4.8 18 .8 8 .3 36.3 6 .0 

16 10.9 5.7 9.9 4.5 42 .1 7 .2 

17 10.9 4.3 7.2 4.9 36.0 7 .8 

18 16.2 7.0 19 .9 5 .4 

19 12 .1 7.6 35 .4 7 .6 

20 18 .7 7.6 

21 12.1 5 .5 

22 15 .4 6 .1 

23 8.8 4 .7 

24 9.9 5 .0 3.7 2 .6 

25 16 .6 7 .0 4.2 2.0 

26 16.5 8 .0 26.0 9.4 

27 16 .1 7 .4 7.0 5 .1 

28 19 .9 7 .4 12 .7 6.8 

29 12 .9 6.1 14 .1 6.6 

30 10 .1 4.5 7.9 5 .3 

31 

# Hours 54 482 381 599 

Maximum 10 .3 19 .9 25 .0 42.1 

Arith-Mean I I 4.8 I I SJ I I 5.6 ' I 4.8 

'boxes indicate less than 75% (18 hours) complete. 

95 
Table 26 continued . 

October 1997 November 1997 December 1997 January 1998 

Day Max Avg Max Avg Max Avg Max Avg 

1 15 .1 6.5 24.9 7.1 6.2 4.0 2.5 1 .0 

2 11 .6 8.5 10.6 4.7 7.9 4.4 3.5 1 .2 

3 29 .7 7.7 13 .4 6.7 37.4 13 .7 2.4 1 .0 

4 34.5 6.5 9.2 2.9 6.9 3 .2 4.1 0.8 

5 2.4 1 .5 27.1 6 .1 5 .9 2 .6 19.1 3.8 

6 12 .4 1 .7 24.2 7.1 6.8 3 .4 8.7 2 .3 

7 3.5 1 .0 16 .9 4 .6 6.3 3 .1 18 .0 7 .1 

8 3.6 1 .1 7.4 5 .6 32 .4 10 .4 4 .9 2 .7 

9 4.3 0 .8 5.5 3 .9 32 .2 14 .8 10 .4 3 .8 

10 4.2 0 .7 20.5 6 .6 8.9 5 .6 5 .1 2.2 

11 1 .0 0 .5 13 .2 5 .1 14 .4 7.6 4.6 1 .2 

12 59 2 .0 25.3 6.0 14 .4 5.4 20.6 7.7 

13 26.4 8 .4 29.2 11 .6 5.7 3.4 10 .9 4.9 

14 4.1 2 .4 15 .6 8 .4 5.4 1 .7 23.9 7.2 

15 5 .8 3 .5 7 .9 4.6 27.9 93 17.1 5.0 

16 10 .0 4.8 4.6 2.8 39.7 22 .9 18 .5 8.2 

17 9.9 5 .5 5 .1 2.8 47.8 23 .8 40.2 16 .5 

18 5 .8 3 .6 5 .0 2.8 41 .5 18 .1 20.4 13 .7 

19 9.0 3 .4 14 .8 4.1 32.9 12 .9 4.7 1 .9 

20 19 .4 8.0 25.5 7.9 22.6 5.9 3.1 0.9 

21 52.9 15 .6 38.6 19.7 26.8 10 .0 3.3 1 .2 

22 8.2 4.4 13 .8 8.1 24.7 8.2 14 .8 3.7 

23 22 .3 8.0 7.6 4.7 13 .0 5.9 13 .5 7.3 

24 20 .0 5.7 5 .3 2.8 17 .5 7 .0 4.9 2 .3 

25 23 .5 11 .1 6.0 2.5 19 .1 5 .7 2.6 1 .1 

26 12 .5* 4 .1 * 35 .2 8.1 12 .1 4.2 11 .5 2 .7 

27 5.0 3.3 41 .5 10 .2 2.4 0.7 5.6 1 .5 

28 4.9 3.5 17.0 6 .3 20.1 4.0 26.7 7.4 

29 7.4 3.3 21 .8 8 .9 3 .0 1 .7 38.3 16.5 

30 10.2 3.4 10 .2 5 .5 15 .3 6.0 40.2 13 .9 

31 25 .8 6 .7 10 .1 3 .5 5.9 2.7 

# Hours 736 713 740 738 

Maximum 52.9 41 .5 47 .8 40.2 

Arith-Mean 4.8 6.3 I 7.5 I I 4.9 

boxes indicate less than 75% (18 hours) complete. 

96 
Table 26 continued. 

February 1998 March 1998 April 1998 May 1998 

Days Max Avg Max Avg Max Avg Max Avg 

1 4.2 1 .4 3 .8 2.6 2 .5 0.8 26.6 10 .1 

2 3 .2 1 .0 7 .6 3 .7 19 .0 8.5 10 .8 6.8 

3 2.9 1 .0 10 .2 3 .4 20.8 7.8 11 .8 7.6 

4 6.1 3 .2 12 .2 6.2 8 .4 1 .5 48.7 11 .2 

5 5 .7 3 .2 15 .7 5.9 9 .0 2.4 37.4 10.6 

6 10 .2 4.3 11 .8 4.1 8 .3 4.3 37 .2 20.7 

7 14 .7 6.4 7.8 3.0 20.3 10 .5 13 .6 8.5 

8 23 .4 9.5 7.5 4.4 25.1 7.9 14 .8 8.3 

9 35 .5 12 .6 4.6 3.0 6.2 2.7 27 .5 12 .6 

10 12 .1 5.1 2.5 1 .6 3 .0 1 .6 6.7 5.3 

11 8.1 4.4 4.3 2.6 12 .0 2 .1 12 .1 6 .6 

12 21 .9 9.0 5.9 3.1 20.1 9 .3 45 .1 11 .5 

13 11 .6 6.5 21 .1 4.2 13 .6 5 .6 48 .0 16 .7 

14 7.9 3.8 20.6 5.7 19 .2 12 .2 51 .6 29.7 

15 9.1 3.3 8.5 3 .4 21 .6 7.4 39.5 21 .1 

16 13 .9 4.3 11 .3 4 .0 17 .9 4.1 13 .5 8 .4 

17 9.4 4.1 9.6 2 .1 23 .1 10 .9 18 .4 8 .4 

18 9.0 5.1 14.1 3 .3 14 .0 6.2 18 .8 7 .7 

19 7.6 4.1 17 .9 5 .9 1 .4 0.4 17 .1 9 .3 

20 22.8 10 .9 8.4 3 .6 3.0 1 .0 28.0 12 .8 

21 2.3 0.6 8.7 4.3 14 .1 8.0 

22 5.3 4 .0 7 .9 1 .7 9.0 5.3 35.6 10 .6 

23 4.9 2 .9 20.5 8 .7 5.2 5.2 23.2 9.8 

24 23.3 10 .1 35 .8 12 .1 43.8 23 .6 

25 5.2* 3 .0* 9 .4 4.6 59.9 28 .8 38.6 15 .8 

26 10 .3 4.6 11 .1 3 .0 47.1 14.6 44 .3 16 .2 

27 5.8* 4.0* 2 .4 1 .1 22.6 8.7 30 .9 8.5 

28 4.4* 3.0* 9 .0 2.2 21 .0 7.0 28 .1 9.9 

29 8 .0 1 .8 34.7 7.8 31 .1 15 .0 

30 15 .9 2.9 35.5 8.7 27 .2 9.8 

31 20 .3 6.8 10.4 6 .0 

# Hours 550 739 674 744 

Maximum 35 .5 23 .3 59.9 51 .6 

Arith-Mean 4.9 3.8 r 7 .0 I I 11 .8 

boxes indicate less than 75% (18 hours) complete . 

97 
Table 26 continued. 

June 1998 July 1998 

Day Max Avg Max Avg 

1 16 .0* 7.2* 11 .9 7.6 

2 35 .0 12 .9 

3 32.0 17 .6 

4 17 .4 8 .9 

5 11 .4 6 .6 

6 20.4 9 .6 

7 31 .9 12 .3 

8 15 .8 8 .9 

9 14 .6 7 .6 

10 14 .7 8 .0 

11 10 .6 6.7 

12 9.7 6.1 

13 9.9 6.2 

14 5.2* 4.3* 23 .4 10 .4 

15 6 .9 4.9 13 .9 7.1 

16 11 .4 6.9 12 .9 8.0 

17 20.9 10 .0 18 .3 9.9 

18 18 .5 92 30 .2 10.5 

19 13 .0 6.3 23 .5 9.7 

20 23.4 8 .4 23 .8 11 .0 

21 22.2 9 .6 28 .8 12 .6 

22 22.0 10 .0 25 .4 12 .9 

23 39.3 9 .3 12 .4 8.4 

24 26.3 7 .6 21 .6 9.1 

25 32.0 12 .2 26.7 11 .1 

26 23.0 10 .6 8.9 7.0 

27 23.0 11 .9 24.2 8.4 

28 28 .1 12 .7 12 .3* 10 .2* 

29 16.1 11 .4 

30 15 .4 8.2 

31 

# Hours 409 657 

Maximum 39.3 35.0 

Arith-Mean 9.1 ~ 9.5 

boxes indicate less than 75% (18 hours) complete . 

98 
30 

R. 

Q" 25 

20 

c. 

Q 15 

~. 

10 

M 

5 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

30 

R. 

25 

20 

~. 

Q 15 

~. 

,mo o,10 

M 

5 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 

Figure 50. Breton Island annual SOZ trends based on 3-hour block averages . 
30 

a a" 25 

20 

~ . 

15 

10 

M 

5 

0 0 

0 

1 

30 02 

a 

a 

R' 25 

20 

~. 

15 

~. 

10 

M 

5 

0 

1 

31 61 91 121 151 181 211 241 271 301 331 361 

Figure 50 continued. 

31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 
is 

a 

w 

12 

on 

9 

d 

6 

0 

x 

ev 3 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

0 

15 

a 

a 

~' 12 

9 

6 

0 

x 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 

Figure 51 . Breton Island annual SOZ trends based on 24-hour block averages. 

0 
15 

a 

a 

12 

oA 

9 

d 

6 

0 

x 

eV 3 

0 N 

0 

1 

15 

c4 c4 

12 

on 

9 

d 

6 

0 

x 

00 

r, 

0 

1 

31 61 91 121 151 181 211 241 271 301 331 361 

Figure 51 continued. 

31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 
80 

70 

60 

z 

o~ so 

ao 

d 

30 

0 

x Zo 

10 

1 31 61 91 121 151 181 211 241 271 301 331 361 

80 

~ 70 0 

w ~v 

U 60 

z 

so 

40 

d 

30 

0 

x Zo t + 1 

10 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 

Figure 52 . Breton Island annual NOz trends based on 3-hour block averages. 
0 

80 

a 70 

60 

50 

40 

d 

30 

0 

x ao t7 

10 

1 

80 

70 

60 

ao 50 

c. 

40 

d 

30 

0 

x Zo 

00 

10 

0 

1 

31 61 91 121 151 181 211 241 271 301 331 361 

Figure 52 continued. 

31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 
35 

3 o0 

25 

an 

y 20 

d 

~, 15 

0 

x io 

N 

0 

1 31 61 91 121 151 181 211 241 271 301 331 361 

0 

35 

c4 R" 30 

z Zs 

Zo 

d 

15 

0 

x io 

N 

5 

`' l 

1 31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 

Figure 53 . Breton Island annual NOZ trend based on 24-hour averages . 

0 
0 

35 

3 o0 

25 

20 

15 

10 

N 

5 

0 

1 

1 

35 

a 

30 

z is 

Zo 

d 

15 

0 

x io 

N 

5 

0 

1 

31 61 91 121 151 181 211 241 271 301 331 361 

Figure 53 continued. 

31 61 91 121 151 181 211 241 271 301 331 361 

Julian Day 
1.2 -

1.0 -

0.8 -

0.6 -

0.4 - 

0.2 

0 .0 

1 .0 

~, 0.8 

V 

c~ 0.6 -

0.4 -

.2 - 

0.0 

1 .2 

1 .0 

0.8 

0.6 

,~ 0.4 

0.2 

0.0 2.0 

~ i.s 

1.0 

o.s 

RI 

`. 

--- 

r 

r 

J 

/'~ 

`\ 

-. ~` 

i `. 

f 

i ' 

,. 

S I I ~ 

00 01 !5 . 

v 

0 7 : 

--- - _-' ---- - 

. . . . . . . ~ . . . . . . . . . . . . . 

`. 

. " " , --_ - ,. 

_ . ." 

- 

- 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 54. Breton Island diurnal SOZ trends as represented by first (dashed), second (solid), and 

third (dashed) quartile lines. 

107 
4.5 

4.0 

O 3.5 -

3.0 -

v~ 2.5 -

s, 2.0 - 

1 .5 -

0 

1 .0 

0.5 -

0.0 _ 

3.5 

b' 3.0 -

.5 

Q` 2.0 - 

1 .5 -

1 .0 - 

z o.s -

0.0 

3.5 " 

3.0 

2.5 -

2.0 

1 .5 - 

A 

1 .0 

o.s _ Z.s 

N 

.0 

1.5 

CC 

1 .0 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 54 continued . 

.' ` . 

;. 

-, 

T-~ -- ~ - 

' ` " -- 

, " ` " 

- - - - - - - - - - - - - - - 

i 

--.v - - - - - - - - - - - - - 

. . . . . . . . . . . . . . . . . . . . . . 

i 

i 

00 

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

108 
4.0 

3 .5 

3 .0 

00 

2 .5 

~" 2 .0 

1 .5 

1 .0 

0.5 

0.0 

1 .4 

1 .2 

1 .0 

0.8 

0.6 

v 

0.4 

0.2 

0.0 

2.5 

~, 2.0 

1 .5 

1 .0 

R. 

d 0.5 

i i 

" i ~`-- 

-------------- ------------ 

---, ' , .%,++ , 

t 

. ..-

---- 

0.0 

rye~ 1 '1 1 1 1 1 1 1 1 1 1 1 ~ 1 _ti~~~7w 1 7~ 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 54 continued. 

109 
z 

h 

V 

z 

ON 

h 

io -

9-

8- 

6-

5-

4- 

3-

2_ 

10 

9- 

O 

6- 

4- 

3-

8-

7-

z 

6-

°; 5 

4-

3 -

a 2 

1 

8-

7 

z 6-

5 

s, 4 -

0 3-

V 

1 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 55 

.-- --, " . 

I. '- 

- 

- - - - - - - - 

- - - - - - - - - - - - 

I- - - - +. .. . 

i 

\ ~ I 

i 

a 

' , 

I 

r .--i 

--- -- ~ -, 

.. 

`. 

" - . 

__ .. ~..- 

- - - - - - - - - - - - - - - - - 

--- 

--.. 

' 

v 

~~--- 

- 

_. 

w~~\ ~/ V 

Breton Island diurnal NOZ trends as represented by first (dashed), second (solid), and 

third (dashed) quartile lines. 

110 
12 -

10 - 

°' 6 -

4-

0 

z 2 

14-

12 -

z 

~ io -

s- ~ . 

a> 

6-

4- 

A 12 " 

10 

0o g 

6 

ca 4 

0 

8 

V ' 

00 6 

5 

4 

3 

cz, 

1 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

". 

14% 

i i 

`. 

~44- 

,. , 

V 

-- -- 

. . . . . . . . . . . 

i 

11 

It 

% 

% 

, .- - ,, 

------------- ------- 

Hour CST 

Figure 55 continued. 
8 

7 

6 

5 

4 

3 V 

1 

0 

14 

12 

10 

00 g 

6 

a 4 

0 

20 

18 

Lv 16 

z 14 

12 

10 

~ 6 

4 

2 

0 

~ ~ -- . 

1 

------------- 

i `. 

.-

-'' -. 

r -__"- ----' 

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 

Hour CST 

Figure 55 continued. 

112 
Monthly wind and pollution roses are given in Figs. 56 - 69 . Higher SOz concentrations are 

very clearly associated with northerly wind directions, particularly north-northeast. High NOZ 

concentrations are more distributed, often from west-northwest directions but mostly from southerly 

directions . Again, it must be noted that the Kerr-McGee generator shed was situated to the southsoutheast of our monitoring station; however the peaks were often observed from the southwest and 

west . Maximum observed concentrations of SOZ and NOz at Breton Island are listed in Tables 27 

and 28, respectively . These directional relationships are further confirmed by the maximum values . 

Lower NOZ / NO,, ratios are found here than at Dauphin, suggesting a much nearer source (less NO, 

to NOz conversion). For comparison to the NAAQS (Table 23), maximum 3- and 24-hour SOZ was 

10 .6 and 6.0 ppb; well below both the standard and similarly averaged values at Dauphin. 

Table 29 lists the statistics for the top 10% of the Breton Island air quality data for this study 

period . The winter peak in SOZ concentrations from October to January is pronounced; N02 exhibits 

dual peaks in early winter and late spring . More importantly, the opposite directional dependence 

of SOz to north and NOZ to south is apparent. North and northeast of Breton Island is the 

Chandeleur Sound and eventually the Mississippi Gulf coast; to the south and southwest is the 

Breton Sound and the Mississippi River Delta. Numerous oil and gas platforms are active in these 

coastal waters . Obviously then, this location can be exposed to a wide variety of sources, both landbased and marine; however identification and quantification of sources is beyond the scope of this 

work . 

In order to determine the synoptic weather regimes most frequently associated with high 

pollutant concentrations, the classification scheme of Muller (1977) is employed. A brief 

description of each synoptic type is as follows (see Fig. 70) : 

Pacific High (PH) : following a "Pacific" cold front, this weather type is normally fair and 

mild with west to northwest winds. Ahead of the front, stronger southerly wind may prevail. 

Continental High (CH) : associated with polar or arctic outbreaks . North or northeasterly 

winds will prevail over a large section of the Gulf. 

Frontal Overrunning (FOR): cloudy and rainy type occurs frequently when cold fronts 

become stationary along the Gulf coast or northern or central Gulf. 

Coastal Return (CR) : wind around high pressure over east Canada will bring southeasterly 

and southerly flow over Gulf. 

Gulf Return (GR) : similar to CR, wind direction is mainly from southeast and south but 

speed is higher due to developing low pressure system over Texas. 

Frontal Gulf Return (FGR): when cold front is approaching Gulf from northwest, return flow 

ahead of front becomes increasingly turbulent and stormy . 

Gulf High (GH): high pressure system prevails over Gulf, calm weather results. 

113 
Gulf Tropical Disturbance (GTD): any tropical weather system prevails over Gulf. 

The 1995 - 1998 annual records at Breton Island were ranked by 24-hour block average, and 

the top 20 days (about 5%) selected. The synoptic weather type present at New Orleans, Louisiana 

on these days as supplied by the "Louisiana Monthly Climate Review" (LOSC, 1995 - 1998) was 

determined. Table 30 lists these results . Maximums in SOZ concentrations throughout the record 

are mostly associated with CH and FOR types ; NO2 maximums are more distributed but usually seen 

under GR, FGR, or CH types. This analysis is consistent with previous findings in that higher SOz 

occurs when wind blows from land to sea (CH), while high NOZ is seen mostly when wind blows 

from sea to land (GR) . It is interesting to see that a high percentage of NOZ - CH cases are found, 

as the northerly wind - NOZ relation was detected in the pollution rose analysis . Note that under 

FOR conditions, winds can either be from sea to land or land to sea, depending on location of the 

stationary front . This analysis may be slightly biased toward weather types commonly associated 

with the fall-winter seasons, since more of the air quality data was collected during those periods 

(from the time series depicted in Figs. 51 and 53, it is seen that the data return was higher during the 

winter seasons) . 

114 
Breton Island 

May 1-May 31 ; Midnight-11 PM 

i , - - ~ 

% 4%\sx \

b1f \

1ox113x

1115 l6f 

l I l / / 

r ~ I ~ 

s 

CALM WINDS 0.13 % WIND SPEED (KNOTS) 

NO7E : Fre9- L6 .21 

7

.1p 11-i6 17'Zi~mlrA'rmion 

~ UG/5 

wib ii Dbwind. 

N 

I 

4% 

E 

Zero Conc. 70.66% Concentration ppb 

y 7I0 II-16 1721 L+11 

Figure 56. Breton Island May 1997 wind (top) and pollution roses (SOz bottom left, NOZ 

missing) . 

115 
Breton Island 

June 1-June 30; Midnight-II PM 

N 

W 

12% 

16% 

44 % 

S 

CALM WADS 0.28% W/ND SPEED (KNOTS) 

N07E: Frpumdn 

~ 7-l0 11 .16 17 21 r11 

i~me drmion 

Jm~n Mich Ue ~~5 

rind is hl-mg. 

~ 

`los e:s 

~ I x ~ Ib; ~ ax 

I 

- - / / ~ 

_ - - ~ i 

E 

/ \ \ 

l / / ! \ \ \ ~7x \ ass \ ms 1

:~s MI 

~ les I I I I 

- - 

i 

- - 

s s 

Zero Conc.41 .70% Concentration ppb Zero Cone. 0.2/% Concentration ppb 

AIO lI-16 IATI X31 

~ AIO 11-16 17-11 +11 

ld 

Figure 57 . Breton Island June 1997 wind (top) and pollution roses (SOz bottom left, NO2 bottom 

right) . 

116 
Breton Island 

July 1-July 23; Midnight-/1 PM 

i 

\6~ \ax 1~os ~ux "x 

I 

i 

\ -_-- 

s 

CALM WINDS 0.00% WIND SPEED (KNOTS) 

NOl£r£rpum~ia 

~ 7.I0 11 16 17-31 t1l 

iMim~r d'rmion 

Jrvln wiSiA tar CAMS 

wiMlt bbwind . N 

i 

\ \ 

/ , - 

/ \ ~ ~6i ~as 

~ios i:x 

E 

i 

/ ~ \ \ \ 

6; ~ as \ ios ~vx 

ins 

~x_~.` i I ~ I E 

. ' / 

S S 

Zero Cone. 52.14% Concentration ppb Zero Conc. 0.00% Concentration ppb 

1121 .21 

,s -o a-s 

°~ 

1-3 se 7d0 11 16 

Figure 58 . Breton Island July 1997 wind (top) and pollution roses (SOZ bottom left, NOZ bottom 

right) . Note that Hurricane Danny occurred during this month. 

117 
Breton Island 

September 1-September 30; Midnight-I] PM 

N 

12% 

E 

N 

i 

E 

I 

I 

- - ~ / 

E 

S S 

Zero Cone. 38.06% Concentration ppb Zero Cone. O.oo% Concentration ppb 

.y AIO 14(6 IZ11 .3l Fy 7d0 

1-3 

11161121 .21 -

Figure 59 . Breton Island September 1997 wind (top) and pollution roses (SOZ bottom left, NOz 

bottom right) . 

118 

S 

CALM WINDS 1.81 % WIND SPEED (KNOTS) 

N07E : Pn9uenda 

7_10 1I .16 1721+21 

i~~wseimnion 1-3 I6 

/mm wNCh rhr (

.'AWS 

wirW ii Dbwing. 
Breton Island 

October 1-October 31 ; Midnight-II PM 

121 

\ - .-. - / 

6 

E 

S 

CALM WINDS 0.13 % WIND SPEED (KNOTS) 

NOTE: Frsqumdo 

110 

1116 17-31 +31 

iMiaweGrrmon I-3 

JhHn whirl rhr C'.UwfS 

wiM a bbhind. 

N 

/ \ 

\61f \9t 

I10" 

!Sf 

I " 

I I 1 '\ 

\ 

\ 

i 

- - ' ~ i 

N 

/ ~ i \ \ \ \ 

l ~ ~ ~ 16 " 

I I l / 

IL\611\Qx\1011\l7

.111x 

I I I I 

I I' 

i 

- - 

Zero Cone. 25 .14% Concentration ppb Zero Conc. 4.89% Concentration ppb 

"0 II-l6 17.11 h1I 

~ Al0 II-16 1741 71 

Figure 60. Breton Island October 1997 wind (top) and pollution roses (SO2 bottom left, NOZ 

bottom right) . 

119 
Breton /stand 

November ]-November 30; Midnight-II PM 

N 

I 

_ - - i 

1~ox 11% 

I 

I 

i 

S 

CALM WINDS 0.00% WIND SPEED (KNOTS) 

Non: Frcpusuia ~_~0 II-l6 1721 121 

iidimrcdrcvar /-3 46 

from MiA I/u CA(.NS 

wndu Dlowind, 

N 

12% 

E 

Z 

6% 

4% 

E 

S S 

Zero Cone. 16 .13% Concentration ppb Zero Cone. 0.00% Concentration ppb 

~ AIO Ild6 77-21 X71 ,3 ~ _~ 11-I6 17-11 III 

Figure 61 . Breton Island November 1997 wind (top) and pollution roses (SOZ bottom left, NOZ 

bottom right) . 

120 
Breton Island 

December 1-December 31 ; Midnight-ll PM 

N 

/ ~ \ \ \ 

' l 6% \ as \ pox `~zx 1 14x isx 

I I I I 

\ ~ \ \ ~ 

- - 

s 

CALM WINDS 0 .13 % W/ND SPEED (KNOTS) 

NOTE: FieqYeziei I1-76 17-31 +II 

IM'ovrArcnion 1 .3 

_7 -/0 

/min whiM Us LI(.NS 

wiM It bbwin;. 

N 

w 

~ ~ \ \ \ 

/~ ~ ~ \ \ \ \ 

esx 

I l / ~ ~x\ ss \ es \ ion 1 ins \14% 

I I I I 

I ~ I 1 1 I~ / I I I I 

i 

- _ \ 

i 

/ / - - \ ~ \ \ 

~ / \ \ \ \ 

4s i x \ ax 

\pox 

`i7s ins 

w I I I 1 I ~ ~ 

l 

s s 

Zero Cone. 5.14% Concentration ppb Zero Cone. 2 .70% Concentration ppb 

7.10 ll .l6 0-11 f71 

13 

~ .0 I4I6 O.3/ X31 

Figure 62. Breton Island December 1997 wind (top) and pollution roses (SOZ bottom left, NOz 

bottom right) . 

121 
Breton /stand 

January 1-January 31 ; Midnight-11 PM 

N 

E 

N 

\ \ \ 

ax 

~ ~ ~ / 

s~ .x 4 \ax `gas `us 

I I 

E W 

6 

I I I I / I 

i 

i 

- - 

S 

Zero Conc. 11 .52% Concentration ppb 

y 7-10 11 .16 17-11 ~11 

Figure 63 . Breton Island January 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

122 

S 

CALM WINDS 0.13 % WIND SPEED (KNOTS) 

NOTE. fmpuekin ~_~Q 11-16 17-21 +11 

iMiaw~dirndon I-f I-6 

J -1 - ~S 

xird it Dbxing . 

S 

Zero Conc. 2.30% Concentration ppb 

1I-16 1

- 
Breton /stand 

February ]-February 28; Midnight-/1 PM 

N 

- , \ 

!Ix 

l x\ "x \ 6% ~ 

84 1 f0% 

112% 

I ' I ~ E 

I 1 ~/ I 

\ \ \ \ \ - - 7' ~ I 

- - ~ i 

S 

CALM WINDS 0.60% WIND SPEED (KNOTS) 

NOTE: frrqumda ~.~p (I-16 17.71 +11 

i~raeAreRion !-3 16 

Jrom Mi~h ire C'ALVS 

wiM u 6Wwin8 . N 

i 

- . \ 

l l / 

~ I ~ ~ 

;\ ~x \ex \ax `ios ~~7s ux 

I I ~ I E 

i 

- ' i 

i 

\ \ 

' 

; ~dx ~ios `i :s 

ins 

~ 

I I 

I 

4% 

I I ~ E 

\ ~ \~ ~ ~ / 

\ - - , i 

- - 

s 

Zero Cone. 19.17% Concentration ppb 

~ FIO ILI6 I7.L v1/ 

s 

Zero Cone. 6.35% Concentration ppb 

1- 11-16 17-71 i11 

Figure 64. Breton Island February 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

123 
Breton Island 

March 1-March 31 ; Midnight-II PM 

W 

44 % 

17 

12% 

E 

S 

CALM WINDS 0.13 % WIND SPEED (KNOTS) 

N07E.frtqumda ~_~Q I!-I6 O-3! +II 

i~mieAmnlon IJ I-6 

fom wNd Nt ~'U'WS 

mm u Wkq. 

4% 

\6% 

12. 

44 % 

E 

s 

Zero Conc. 53.8% Concentration ppb Zero Conc. 8 .25% Concentration ppb 

11-76 17-71 i71 

~ 7-10 11.16 1,21 +31 

I-3 

Figure 65 . Breton Island March 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

124 

' / I - _ \ 
Breton Island 

April 1-April 30; Midnight-11 PM 

N 

w 

i 

l / \ \ 

1SS \ 16~ 1 

7 

11x 

I 1.. 

hex I 

I 

/ 

\ ~ - - \ \ ~ / 

~ 

- - / / 

- ' i 

\ ~ - - - 

S 

CALM W/NDS 0.00% WIND SPEED (KNOTS) 

N~~ FN-. ~.~p 11-I6 17-21 +31 

l~'rarmmttton 

fomwNAUe GLNS 

wiM u 6bwind. 

N 

i 

I / \ \6; \8i 

I/011 

I I I\ I I\ ; ~ ~ 

E x' 

i 

i 

~ \ \ 

/ / \ \I]" 

\16S 

1b14 

I I 

I I ~ 1~~ 

~ax i I I 

\ \ \ - - / / 

E 

S S 

Zero Conc. 41 .54% Concentration ppb Zero Cone. 8.46% Concentration ppb 

/IJ6 1ZII +11 I3 ~ AIO II-I6 1121 i31 

I-3 

Figure 66. Breton Island April 1998 wind (top) and pollution roses (SOz bottom left, NOZ 

bottom right) . 

125 
Breton Island 

May 1-May 31 ; Midnight-11 PM 

ros 

E 

N 

Ai l 

~

11R 1 11" 

1 

10x 

BA 

I ~ E W 

\ / 

S 

Zero Conc. 2 .42% Concentration ppb 

fldb 1731 i71 

I-J 

Figure 67. Breton Island May 1998 wind (top) and pollution roses (SOZ bottom left, NOz bottom 

right) . 

126 

S 

CALM W/NDS 0.40% WIND SPEED (KNOTS) 

NOM F,,-. l/d6 I1-11 ail 

i~'cwedmrian 1-3 Ifi 7-10 

/rvin ~MiA r/1e ('A(JIS 

wiM u bbwiy. 

Zero Conc. 0 .00% Concentration ppb 

41 - II-I6 1Z11 r11 

/J 
Breton /stand 

June 1-June 30; Midnight-11 PM 

I ~ / / ~ \ \l1~ 

116% 

R 

10% 

E 

S 

CALM W/NDS 0.70 WIND SPEED (KNOTS) 

NOTE: Frrqueuio 11-16 17-21 r3i 

i~mrsdrMion 1-3 _7 -/0 

M m vN'M efr CAl.NS 

b u Db~in`. 

N 

i 

/ / , - \ \ \ 

/ _ ~ ~ ~i:x 

~~ss 

ms 

as 

w "~ ~ I I I 

1 

- ' i 

Zero Conc.5.38% Concentration ppb 

~ LIO II-l6 

1 

7-11 NI 

Figure 68 . Breton Island June 1998 wind (top) and pollution roses (SOz bottom left, N02 bottom 

right) . 

127 

s 

Zero Conc. 0.00% Concentration ppb 

7-10 I1-16 1171 v1/ 
Breton Island 

July 1-July 31; Midnight-11 PM 

N 

w 

i 

\ ~ \ 

:4x 

1 mx ux ~ ~sx 

I 

I 

- - / / 

\ - - 

S 

CALM WINDS 0.81 % WIND SPEED (KNOTS) 

NO1E : irrq~e ~_~p !I-I6 1721 ,21 

iMicar~ Amrion 1-3 I-6 

/min wiY~fi ~~r ULNS 

xiM it Obxin~. 

' - - ` \ 

\ 

\ \ \17S 

1161 

ex 

I ~ 

I.s 

- - 

\ \ lit 

116x 

as 

i 

i 

M4 

E 

s s 

Zero Cone. 0 .00% Concentration ppb Zero Conc. 0.00% Concentration ppb 

yl0 II.(6 )A71 +7I / ~ y0 ll.lb 1741 a]I 

I-J 

Figure 69. Breton Island July 1998 wind (top) and pollution roses (SOZ bottom left, NOz bottom 

right) . 

128 
Table 27 . 

Breton Island SOZ Maximums (ppb) 

Month Averaging Interval Maximum Day / Hour Wind Direction / Speed 

May 1997 1 hour 5 .6 10/22 

10/23 

046/6 

048/7 

3 hour 5.5 10/23 048/6 

24 hour 2.4 10 

June 1997 1 hour 2.4 20/8 

23/8 

166/3 

325/6 

3 hour 1 .7 20/8 

22/14 

189/2 

107/2 

24 hour 0 .9 23 

July 1997 1 hour 6 .0 2/9 312/6 

3 hour 4.5 2/11 309/5 

24 hour 1 .8 2 

September 1997 1 hour 10.9 29/ 10 305/3 

3 hour 9.4 29/11 307/3 

24 hour 4.2 29 

October 1997 1 hour 16.8 16/11 000/6 

3 hour 10.6 16/ 14 007/6 

24 hour 6.0 17 

November 1997 1 hour 11 .8 22/21 025/5 

3 hour 6.9 8/11 002/4 

24 hour 4.4 8 

December 1997 1 hour 11 .0 15/12 355/4 

3 hour 8 .6 15/14 343/4 

24 hour 4 .9 15 

129 
Table 27 continued. 

Month Averaging Interval Maximum Day / Hour Wind Direction / Speed 

January 1998 1 hour 7.1 16/08 304/6 

3 hour 5.6 16/11 296/4 

24 hour 4.1 28 

February 1998 1 hour 9 .6 8/02 002/5 

3 hour 7 .8 8/11 035/2 

24 hour 4 .5 8 

March 1998 1 hour 9 .8 23/07 324/3 

3 hour 7 .1 23/08 325/3 

24 hour 2 .9 12,23 

April 1998 1 hour 5 .3 1/06 027/7 

3 hour 3 .9 5/23 161/2 

24 hour 2 .4 20 

May 1998 1 hour 7.7 18/12 

19/22 

048/2 

275/ 1 

3 hour 6.9 18/14 034/2 

24 hour 3 .9 19 

June 1998 1 hour 1 .2 17/03 

18/04 

27/10 

154/2 

153/3 

143/3 

3 hour 1 .1 17 / 21 to 

18/05 

29/08 

145/3 

087/ 1 

24 hour 0.9 17,27 

July 1998 1 hour 1 .7 6/08 330/2 

3 hour 1 .4 6 / 08 322/3 

24 hour 1 .0 9,22 

130 
Table 28 . 

Breton Island NOZ Maximums (ppb) 

Month Avg. Int. Maximum Day / Hour Wind Dir. / Speed NOz / NO,, 

June 1997 1 hour 19 .9 28/11 136/1 0.37 

3 hour 17 .5 20/05 222/4 0.72 

24 hour 8 .0 26 

July 1997 1 hour 25 .0 9/23 331 / 2 0 .94 

3 hour 16 .7 10105 299/2 0 .98 

24 hour 10.3 10 

September 1997 1 hour 42 .1 16/17 164/3 0.38 

3 hour 31 .2 16/17 164/3 0.40 

24 hour 9.4 26 

October 1997 1 hour 52.9 21/16 156/2 0.55 

3 hour 44.8 21/17 154/3 0.58 

24 hour 15 .6 21 

November 1997 1 hour 41 .5 27/01 160/2 0.35 

3 hour 35.5 21/11 165/5 0.32 

24 hour 19 .7 21 

December 1997 1 hour 47 .8 17/00 238/ 1 0 .58 

3 hour 40 .3 17/02 251/1 0 .82 

24 hour 23 .8 17 

January 1998 1 hour 40.2 17/02 

30/02 

221 / 3 

246/2 

0 .98 

0 .95 

3 hour 34.9 30/02 237/2 0.98 

24 hour 16.5 17,29 

131 
Table 28 continued. 

Month Avg. Int. Maximum Day / Hour Wind Dir. / Speed NOZ / NO,, 

February 1998 1 hour 35.5 9/05 144/1 0.93 

3 hour 32 .0 9/05 15511 0.95 

24 hour 12 .6 9 

March 1998 1 hour 23 .3 24/07 157/2 0 .79 

3 hour 20 .0 24/08 157/3 0 .82 

24 hour 10 .1 24 

April 1998 1 hour 59 .9 25/07 167/3 0 .45 

3 hour 49.0 25/11 161/5 0 .53 

24 hour 28 .8 25 

May 1998 1 hour 51 .6 14/07 161/2 0.52 

3 hour 43 .9 14/05 158/2 0.54 

24 hour 29.7 14 

June 1998 1 hour 39.3 23/21 155/3 0.57 

3 hour 30 .6 23/23 156/2 0.62 

24 hour 12 .7 28 

July 1998 1 hour 35 .0 2/22 156/4 0 .42 

3 hour 28 .0 3/11 161/3 0.47 

24 hour 17 .6 3 

132 
Table 29 . 

Breton Island Top 10% Frequency Distribution by Month and Direction 

Month NOz (710 samples) SOZ (686 samples) 

May 1997 184 9 

June 1997 22 0 

July 1997 24 7 

August 1997 Missing Missing 

September 1997 34 45 

October 1997 43 182 

November 1997 65 125 

December 1997 124 121 

January 1998 69 59 

February 1998 27 83 

March 1998 29 30 

April 1998 89 25 

Direction 

0-45 9 239 

46-90 4 94 

91 - 135 41 18 

136- 180 402 22 

181 -225 124 29 

226-270 47 37 

271 -315 44 83 

315-360 33 143 

Missing 6 21 

133 
, . 

5 

_ y - 

' 

r 

Pacific High ~ ' Continental High 

-\ 

_ ~ ~ w o ~ ~ , , L~'r4 

v 

y _ 

V 

_. ; 

-, 

- Frontsl Coastal Return 

Overrunning 

v 

... _ _ 

. `. ' 

" \ / ` 

V S 

I 

\ Gulf Return Frontal Gulf 

If - 

i 

Return 

I / 

I 1 ' ` ,,~ 

v 

r 

, 

i 

' 

~` J 

v 1 ~'" ~ W O O ~ 

~J` / w 

~ {/7`1 

r t ~ 1 

r 

F 

-_ Gulf Tropical 

Gulf High Disturbance 

i , . , 

Figure 70. A classification scheme for synoptic weather types affecting New Orleans, Louisiana 

and the northeast Gulf of Mexico (after Muller, 1977) . 

134 
Table 30 . 

Frequency of Occurrence of Synoptic Weather Types Associated 

with Peak Pollutant Days at Breton Island 

Breton SOz 

Synoptic Type 1995 1996 1997 1998 Total 

PH 0 .5 0 0.5 1 .5 2 .5 3 .1 

CH 5 .5 14 12 10.5 42 52 .5 

FOR 6 3 .5 5 .5 0 15 18 .8 

CR 0 0.5 0 .5 3 4 5 

GR 2 1 0 0.5 3 .5 4.4 

FGR 4.5 0 0 .5 1 6 7 .5 

GH 0.5 1 1 3.5 6 7.5 

GTD 1 0 0 F--0 1 F 1 .3 

Breton NOZ 

PH 1 .5 0 0.5 0.5 2.5 3 .1 

CH 3 .5 2.5 7 1 .5 14 .5 18.1 

FOR 5 3 .5 3 .5 1 13 16 .3 

CR 1 0.5 1 .5 2 .5 5 .5 6 .9 

GR 4.5 9 .5 4 8 .5 26.5 33 .1 

FGR 3 3 3 1 .5 10.5 13 .1 

GH 1 .5 1 0.5 4.5 7.5 9 .4 

GTD 0 0 0 0 0 0 

135 
C. Station Comparison 

Monthly mean and maximum pollutant concentrations recorded at Breton and Dauphin 

Islands during the period of May 1997 through April 1998 are listed in Table 31 and graphed in Fig. 

71 . Mean SOz values at Dauphin are almost twice those observed at Breton, particularly during the 

winter months ; maximum values are also much higher . With the exception of April 1998, mean 

NOz values are almost equivalent, while NOZ peaks at Breton are generally higher . 

From Figure 72a - e, there is good agreement between stations in simultaneous trends of the 

24-hour average SOZ data. Much less correlation is seen in the NOz trends . This suggests that the 

SOz maximums at both stations are often produced by the same air mass, while high NOZ may be 

produced by different, more localized, conditions. 

Four episodes were selected in which near simultaneous peaks of SOz and NOZ were 

recorded at both Breton and Dauphin Islands; one with higher concentrations at Breton than Dauphin 

and the other with Dauphin greater than Breton. Meteorological conditions associated with these 

peaks are discussed as follows. 

Table 31 . 

Summary of Breton and Dauphin Islands Monthly Air Quality Values (ppb) 

SOz NOZ 

Dauphin Island Breton Island Dauphin Island Breton Island 

Month Max Avg Max Avg Max Avg Max Avg 

5/97 16.3 1 .1 5 .6 0.4 22.1 3 .3 10.3* 4.8* 

6/97 11 .1 0.8 2.4 0.5 17.9 3 .4 19.9* 5 .7* 

7/97 42 .5 2.0 6.0* 0.6* 27.4 5 .1 25.0* 5 .6* 

8/97 13 .5 1 .8 19.0 3 .7 

9/97 38 .0 3 .3 10 .9 1 .1 22 .4 4.3 42 .1 4.8 

10/97 37 .1 3.8 16 .8 1 .9 28 .0 6.3 52 .9 4.8 

11/97 29.3 3 .2 11 .8 1 .7 28 .7 6.1 41 .5 6.3 

12/97 50.5 3 .5 11 .0 1 .8 51 .4 7.6 47 .8 7.5 

1/98 22.4 2 .4 7 .1 1 .4 33 .5 5 .8 40.2 4.9 

2/98 23 .0 2 .5 9 .6 1 .5 22.0* 4.1 * 35 .5 4.9 

3/98 17.0 1 .5 9.8 0.9 19.6 1 .8 23 .3 3.8 

4/98 13 .7 1 .5 5 .3 0.9 14.6 1 .2 59.9 7.0 

Annual 2.3 1 .2 4 .4 6 .2 

' boxes indicate less than 75% complete . 

136 
4 

a 

.a ` 

a 

a 

N 

~. 

R 

s 

c 0 

8 

7 

a 6 

a 

N 

O 5 

C 

R 

4 

t 

c 0 3 

2 

1 

--~ ~; ~% 

I 

j ~ 1 / 

Dauphin 

---~---- Breton 

5/97 6/97 7/97 8/97 9/97 10/9711/9712/97 1/98 2/98 3/98 4/98 

Month 

Figure 71 Comparison of monthly mean SOz (top) and NOZ (bottom) values recorded at Breton 

and Dauphin Islands during the study period . 

137 

5/97 6/97 7/97 8/97 9/97 10/9711/9712/97 1/98 2/98 3/98 4/98 
W 

a 

c 

N 

O 

L 

d 

a 

Q 

V 

O 

L 

N 

9 

8 

7 

6 

S 

4 

3 

L 

1 

0 

Breton 

--------- Dauphin 

i 

w 

n 

u 

n 

n 

. . 

. . 

. . 

. . 

1 

1 

1 

1 

1 

T 

1 

i 

w 

n 1 

u 

u 

u 

n 

. . ,~ , 

. . ,~, 

. . 

. . ~ ~ , 

. . 

1 ~ 1 S 1 .. 

.. 

, . . , . . 

11 

I 1 

I 1 I 1 

I 1 I 1 

~ 1 

II 11~ 

~1 ~~ 1 11 

~1 , 

1 I ~ ; ~1 

1~ 1 1 1 

r t l~~ 

h 

4 

q 

h 

h 

i 

" . ~ 

~ 1 1 ~ ~ 1 ~~ ~ 1 1 

1 1 1 

~ 

~ 1 ~ ~ ~ ~ ~ I 1 

1 

~ 

1 

; 1 ~ 1 1 

1 , I 1 

1 

I ~ ~~I 1 

I 1 

~ 1 

~ 1 

~ ~ 1 ~ ~ ~ ~ I 1 

1 ,,~' ~ I 

1/ ~`~ ~I 

31 61 91 121 151 181 

9 

g 

6 

5 

4 

3 

1 

0 

1 

11 

11 ~ 

1 1 ~ i { 

' 1 1 M ~ L 

y 1 1 11 1 S 

S 1 1 

,' 1S; 1 1 1 ~~ 1 1 

1 ; 1 I 1 1 1 1 11 

oil It'. 6, 

i 

.~~I, ~, . 1~~~ j 1 I 

u i i~~ i ; i ~ 

181 211 241 271 301 331 361 

Julian Day 1996 

Figure 72a Time series of 1996 24-hour block averaged SOZ at Breton and Dauphin Islands. 
W 

a 

a. 

O 

z 

on 

L 

d 

Q 

v 0 

L 

0 

0 

N 

22 

20 

18 

16 

14 

12 

10 

8 

6 

4 

2 

11 

' ' '~ ", 

1, ~ I 

1 

22 

20 

Ig 

16 

14 

12 

10 

g 

6 

4 

G 

31 61 91 121 151 181 

Breton 

--------- Dauphin 

u 

n 

., t 

~ti y 

1 0% 

, 

i i 

S~ 

I ~ / ~ ` ~~ N \ ~ 1 ~ V ~ ~ 1 ~ i ~I L \ 1 \ ~/ I 1 I \ 

181 211 241 271 301 331 

Julian Day 1996 

361 

Figure 72b. Time series of 1996 24-hour block averaged NOZ at Breton and Dauphin Islands. 
0 

12 

10 

8 

6 

d 

4 

CD 

ea L 

Breton 

---- ----- Dauphin 

5 

i 

X 11 

i 'u 

~ ~ + 1 ~ ~ ~ I 

1~ 

,, " 

of 

11 

11 

X ~ ~ ~ 

h 

1 ' ! ' 1 11 1 ~ ~ \ 

~ ~ j 11 

11 

to A 

I ' 

1 1 

1 , 

I 

~ 

1 

1 I ~ ~~ 1 

I 

1 1 

t . , 

i i 

Q 

1 

o 12 T 

L 

O ]Q 

x 

N 

6 

31 61 91 121 151 181 

il h 

. . 

,~ . P , . y ~ ~ 

1 , +,I 

1 y + 

. ; . . 

. . ., i 

. ;, . ; . 

.. 

. . , . . ., . . . . 

1 1 ~ n ~ 11 

V ~ 1 j ~,11 q 

~ 17 II YI II 

"~/ ~ 11 ~ 1 I I 1 

I 1~ 

1 

1 1 ~ ~ ~ I 1 ~ 

j I 1 

. . , i . ~ .- , 

181 211 241 271 301 331 361 

Julian Day 1997 

Figure 72c. Time series of 1997 24-hour block averaged SOZ at Breton and Dauphin Islands. 

4 

2 

0 
25 

20 

15 

10 

tZ. 

CY 

O 

z 

o 

L 

Q 25 

U 

O 

ZO 0 0 

x 

N 15 

10 

. . 

. . 

i 

. . 

. . 

. . 

. . 

. . . . . . , . , , . s , 

i 

i 

., 

.' . 

f u 

'~ ; 

i ti % 

, ~ 

,~ 

1 31 61 91 121 151 181 

--------- Dauphin 

Breton 

5 S `1/ 

1 1 \ / ~ 1 ~ / \ \ ~\ //~r 

V1, 

1 1 ~ ~ I ~ ~~ ` ~ ~ 1 1 r~"i V ' 1 1 ~ , ~ / 

1r ; '1 

., 

;1 11 

, . . . 

1 ~1 

1 

4 

1 

. . 

. . 

. . 

h 

11 

r 

`r 

01--

181 211 241 271 301 331 361 

Julian Day 1997 

Figure 72d . Time series of 1997 24-hour block averaged NOz at Breton and Dauphin Islands. 
N 

a 

°, 6 

N 

O 5 

4 

Q 3 

v 

O 

L 

W 1 

N 

~ 11 11 ~~1 

. i . . . . 

. i . . " . , , . 

, . ., 

i . , ~ . ; . , . 

. , 

., 

., 

; . 

. . 

,. 

, . 

. ~ f 

I tell 

1 1 1 ~ ~ 1 1 I 

I 

~ 1 ~ ~ ~ 

' 1 

~ 

~ 

, 

~ ~i 1 1 

' 

, 1 

b. I 

I 

. ; 01 ,. ; 

l~ ; 

S .' 

11 ~ 1 1 y 1 

ii 

~ ~ 11 

1 1 j ~ 1 1 1 

1 ; ; 

1 

1 ~ 1 

1 1 

1 y . 1 \  \~ 1 . J 1 

1 

30 

27 

24 

z 21 

18 

L 

> 15 

Q 

1 2 

0 

3 

N 

31 61 91 121 151 

Breton 

--------- Dauphin 

1 , 

` S 

' ' 

A 

11 ' 

n 

~ 1 1 

11 

1 \ 1 i 

1 31 61 91 121 151 

Julian Day 1998 

Figure 72e . Time series of 1998 24-hour block averaged SOZ (top) and NOZ (bottom) at Breton and Dauphin Islands . 
CH conditions prevail on 28 September 1997 behind a cold front over the northeast Gulf of 

Mexico. A second front attempts to push through on 29 September but becomes nearly stationary, 

and then retreats on 30 September allowing GR weather along the Gulf coast. Pressure rises 

throughout the period at both Breton and Dauphin stations, while surface winds are generally 

westerly . SOZ rises rapidly on 29 September and peaks at about 14 ppb, with Breton maximum 

occurring slightly earlier than at Dauphin. A much higher peak is recorded at Dauphin on 30 

September under westerly flow; Breton also peaks at about 8 ppb, and both decrease as the winds 

become more southwesterly . 

I ~ I67 z 6" ~ ` ~,\~ 

9 1 011 

5 ~~°d~s~ ~-0Lca~~ 

71~" ~ ~z ,~0w 1 JP 

11 

],pip ' ~ ,'~ ! ro1~? ` 

' .. .,.~ 

~~a ~o ~ r 

i 

52 

!'+' 

34 4 91.41, 

io E1G 

y V~ 

sll ~~d'p IF OT 

irk 

roil," 

p=oi  

-. 

, 

~ I}~' . 

. . . n r°~ "? u4; .n 

~r°1 eo ~ro, 

28 September 29 September 

d 

' 

Aoni., ~f` 

re ,~,~n ~t~ 

HIGH 

7 "' r~~ ~y 

5 `-

19 

' ~+"` 1 66 1 

LOW 

c I .rte lGl~ . 

30 September 

Figure 73a. 0700 EST surface weather maps for 28 - 30 September 1997 from NOAA Daily 

Weather Map Series . 

143 
30 

a 25 

a. 

N 

p 20 

on 

15 

>, 10 

L 

7 

x 5 

0 

360 

315 

270 

c 0 

225 

L 

A lOO 

3 135 

90 

45 

0 

1018 

1016 

1014 

.a 

E 

d 1012 

L 

V1 

1010 

a 

1008 

1006 

1004 

Figure 73b. 

Dauphin 

--- Breton 

28 29 30 31 

September 1997 Hour CST 

Meteorological and air quality values observed at Breton and Dauphin Islands on 28 

- 30 September 1997. 

144 
CH and northerly flow dominate during the period of 15 - 17 October 1997, although the 

pressure trend is falling . A SOZ peak is seen at Dauphin on 15 October, but not at Breton . On the 

following day, Breton reaches a maximum of about 17 ppb almost four hours before a lesser peak 

at Dauphin. Note that multiple peaks are evident in the Dauphin record, whereas Breton often 

exhibits a single rise and fall . 

Y 

'7e ~ 

N' - IOy W f~ 

~~oz 7s 7s 

n 

r its o~ 

In 

1-11 

f a 

~g i g 

h_ .a~o=f 7 i ~o~ 

` HIGH , "bib` ~~° 

15 October 16 October 

14 

m 

'P i ~ ~ " ~° ~r 

~p

~

,

`1 , 

33 

I 9~ 

N1J n

~y ~~oe ~511~ 

~go-S, p { -v 

Yal ~. . 

jig

. .'y~ .~v 

'~Sl 

.l Y~ 

~~ 1 

dd 

17 October 

Figure 74a. 0700 EST surface weather maps for 15 - 17 October 1997 from the NOAA Daily 

Weather Map Series . 

145 
20 

16 

O 

12 

L 

i 

Q 

L 

0 4 x 

0 

360 

315 

270 

c 0 

225 

A 180 

135 

90 

45 

0 

1022 

1021 

1020 

1019 

L 1018 

lots 

1016 

1015 

1014 

1013 

Figure 74b 

41 1 

1 1 

1 1 1 

I ~l ; 1 

I 1 4 

Dauphin 

-- Breton 

W46 U 

i 

15 16 17 

October 1997 Hour CST 

18 

Meteorological and air quality values observed at Breton and Dauphin Islands on 15 

- 17 October 1997. 

146 
;!~ r~ .~' ~`'fd. 

. 

2 

~ d Z .. ~^ 

`^ » 

~ y'.I4? I f 

a ; o 

roan+ 

i~e 2 ~1j 

e s,' 

7 I 1As' w,'k~' 

.~y . 

~O° ~ 7 

~P~9f. 

I 1 _ ~ ~ 

y~. 

04 

h~ y ,o 

14 December 

16 December 

15 December 

"I 'Y~~ 

H1G6~e S'A 10 

or 

u 

4 

1 \~ .Itpi 32 I , - 

n 

/ ` HIGH ; I '`t+~` ~~~' 

.-. x 

I uo'-~ ~~ 

5 

17 December 

18 December 

Figure 75a. 0700 EST surface weather maps for 14 - 18 December 1997 from NOAA Daily 

Weather Map Series . 

147 
A cold frontal system has reached the Florida peninsula on 14 and 15 December 1997, 

however FOR conditions remain along the Gulf coast as overcast conditions are seen. By the end 

of the 15`h, the high has moved far enough to the southeast to bring about CH weather. As the high 

center moves eastward on the 16`h, the surface winds rotate from northwest clockwise to westerly . 

Another front washes out over northeast Louisiana on the 17`h, and FOR weather returns on the 18`h 

as winds become more southerly along the coast. A gradual rise in NOZ occurs at both stations, 

reaching a near simultaneous peak of 30 - 40 ppb early on the 16`h with northerly winds. 

Concentrations then fall, but a second higher peak is seen at Breton in the evening under mostly 

westerly flow. Breton NOZ generally remains higher (around 20 ppb) than at Dauphin through the 

18`h . NOZ / NO,, ratios exhibit the expected minimums in the daytime hours, due to dissociation as 

described previously . The ratios are often lower at Breton, suggesting a nearer source, particularly 

the later peak on the 16`n . 

a 50 

40 

30 

Q 20 

10 

0 

0 

1 .0 

0 .9 

0 .8 

z 0.7 

0 .6 

z o.s 

0.4 

0.3 

360 

315 

270 

225 

G 180 

c 135 

3 90 

45 

0 

1026 

1024 

1022 

1020 

0 

1018 

°' 1016 

1014 

Dauphin 

---~--- Breton 

SI 

T~ I 

- 

IT . ., . f 

., Y . . , , .,. . t . . 

T 

~ ~ " ~ 

- 

1 

11 

i 

i 

. . 

1012 

14 15 16 17 18 19 

December 1997 Hour CST 

Figure 75b. Meteorological and air quality values observed at Breton and Dauphin Islands during 

14 - 18 December 1997 . 

148 
FGR weather precedes a front on 22 January 1998 as east-southeast winds are observed early 

in the day . A coastal low merges with the front and moves eastward, causing FOR (note overcast) 

on the 23`d and clearing to CH on the 24`h with northerly flow and rising pressure . NOZ peaks at 

Dauphin at the end of the 22"d are not observed at Breton; both stations show a gradual rise 

throughout the 23rd under northerly winds. NOz / NO,, ratios are similar, indicating a same-aged air 

mass at both locations . 

22 January 23 January 

~s28 173 a ~i 

12 ,. '5t 

937 

-lp~y` 

f~` 

f,/ Sn~y~zjy ~ l 

22 

12 

Air 

. /_ . L. 

(m 4V 

\... . 

24 January 

Figure 76a. 0700 EST surface weather maps for 22 - 24 January 1998 from NOAA Daily 

Weather Map Series . 

These examples further suggest that although similar synoptic meteorological conditions may 

be occurring at both stations, pollutant concentrations may be influenced more by localized sources. 

149 
30 

a 

°' 25 

20 

nn 

15 

Q 10 

5 0 

x o 

1 .0 

0 .9 

0 .8 

o. N 

O 

z 0.6 

o.s 

0.4 

360 

315 

0 270 

225 

L 

180 

c 135 

3 90 

45 

0 

1025 

1020 

E 

11 

1015 

L 

a 1010 

1005 

22 23 24 25 

January 1998 Hour CST 

Figure 76b . Meteorological and air quality values observed at Breton and Dauphin Island on 22 -

24 January 1998 . 

150 
D. Boundary Layer and Dispersion Meteorology Over Breton Island and Sound 

1 . Description of Key Processes in Pollutant Transport and Dispersion Over the Breton National 

Wilderness Area 

a. Topography 

The study area is flat and composed of barrier islands in a chain from Breton Island in the 

southwest (see Fig. 77 and Fig. 1) to the Chandeleur Islands in the northeast. The size of the main 

Breton Island is approximately 1 km wide and 6 km long. It is a relatively flat island . Because the 

islands are so low in elevation, storm surges can change the topography overnight. In fact, the 

overwash generated by Hurricane Danny in July 1997 temporally submerged much of Breton and 

left new cuts across the island . From the vegetative type map of the Louisiana coastal marshes 

published by the Louisiana Department of Wildlife and Fisheries in New Orleans in 1978, the entire 

Breton Island is classified as a saline marsh. The typical vegetation is oystergrass (Spartina 

alterniflora ), Salicornia so. , blackrush (Juncus roemerianus), Batis maritima, black mangrove 

(Avicennia nitida), and saltgrass (Distichlis spicata). 

Even though the island terrain is very low, it can still exert some drag to retard the air flow . 

In addition, the internal boundary layer may develop over this sea-island-sound system (see Hsu, 

1988) . Therefore, the results of turbulence intensity measurements via uvw sensors may not be the 

same as those of open water or further inland . The difference between this barrier island 

environment and the open water will be compared with results obtained from inland environments. 

b. Air-Sea Exchange 

Air-sea exchange includes momentum, heat, and moisture across the air-sea interface. 

Meteorological transport processes in coastal marine environments are important from 

several points of view . For example, the wind stress or momentum flux is one of the most essential 

driving forces in water circulation. Heat and convection are the origin of some localized coastal 

weather systems. Sensible heat and water vapor fluxes are necessary elements in radiation and heat 

budget considerations, including computation of salt flux for a given estuarine system. 

In the atmospheric surface boundary layer, the vertical turbulent transports are customarily 

defined as 

Momentum flux = -p u V = T 

au 2 

-P Km az - P Cd UZ 

151 
Figure 77. Aerial photographs (color infrared) of the northernmost part of Breton Island taken 

on 9 December 1996 (top) and 11 January 1999 (bottom). The Kerr McGee facility 

is visible as the small circular object on the inside of the island . Top of photos is 

oriented approximately to the northeast. 

152 
Sensible heat flux = -p cp w 'T ' 

ae 

= x = P p KH aZ 

= p pCHU20T 

Moisture flux = -p w Iq ~ = E 

a 

- -P KE ~ aq ~ = P CE U~~ 04 

Latent heat flux = HL = Lv E 

The primed values indicate deviations from mean values, which are designated by a horizontal bar; 

p is the air density; u and w are horizontal and vertical components of the wind; UZ is the mean 

horizontal wind at height z; T is the temperature ; q is the specific humidity; cp is specific heat at 

constant pressure; A is the potential temperature ; Km, KH, and KE are eddy diffusivities for 

momentum, heat, and water vapor, respectively ; 0T is the difference between sea surface 

temperature and air temperature at a reference height (usually 10 m above the water surface); Aq is 

the corresponding mean moisture difference; Cd is the drag coefficient (which equals (u, / U,o)z; 

where u. is the shear or friction velocity); CH and CE are bulk aerodynamic coefficients, and Lv is 

the latent heat of vaporization. For practical reasons, averages over a 5- to 20-min measuring period 

are used . 

Under fair (normal) weather conditions when the wind speed is below 10 to 12 m/sec, the 

transfer coefficient across the air-sea interface may be treated approximately as 

= CH = CE. = 1 .2 X 

1 0-3 

Although the variation of CH and CE with wind speed and stability parameters may be 

considered small, the gradual increase of Cd with wind speed must be recognized, that is, 

Cd = (A + B U10) x 10-3 

where A = 0.80 and B = 0.065 are commonly used values . 

c. Wind-Wave Interaction 

Ocean surface waves are mainly generated by the wind. The relationship between 

nondimensionalized wind and wave parameters can be written as 

gH 

3 

= A g a i 

Ulo Uio 

and 

153 
gH 

3 

= B g 'l a 

2 

u, u* 

where g is the gravitational acceleration, HS is the significant wave height, and TP is its 

corresponding peak period . 

For a given region, values of A and B may be considered in equilibrium as constants so that 

wind, waves, and momentum flux are all related through the drag coefficient via 

C 

A 4 

For example, in the Gulf of Mexico, on the average, A = 0.01155 and B = 0.062, so that Cd 

= 1 .2 x 10-' . For the North Sea, A = 0.01048 and B = 0 .054 ; therefore, Cd = 1 .4 x 10"3 . 

For many air-sea interaction studies, e.g., oceanic current generation and Ekman pumping 

and the atmospheric mixing height for the overwater dispersion of pollutants, values of the wind 

stress T (= pu.z = pCdU,o2) are needed. Since direct measurements of u. are not routinely available, 

Cd is commonly employed. Since T is directly proportional to Cd, it is crucial to get as accurate a 

formulation as possible. Published equations of Cd vary greatly (see, e.g., Hsu, 1988, Fig. 6.11, p. 

114). Most recently, Donelan et al. (1993) proposed a formulation in which the aerodynamic 

roughness, Zo, is directly proportional to the wave height and inversely proportional to the wave age. 

These parameters are routinely available . Since Cd is proportional to Zo, younger waves produce 

larger Cd values . Also, shorter fetch can generate younger seas and thus larger Cd. 

At the air-sea interface the near-neutral stability may be assumed when the stability 

parameter IZ/Ll < 0.4 (where Z is the reference height above the mean sea surface and L is the 

Monin-Obukhov stability length) (see Hsu, 1992). Under these conditions, the logarithmic wind 

profile law may be applied that 

u 

Ulo = -' In - 

x Zo 

(1) 

Since u, is not usually measured, the drag coefficient is employed in which 

u 2 

Cd - (2) 

vio 

Because there are two unknowns (i .e ., u, and Zo) in Eq. (1) for a given wind speed, Donelan 

et al . (1993) proposed the following formula for operational applications 

EZ 

6° = B, C'° (3) 

P 

where B, = 6.7 x 10-4, B2= 2 .6, 6 (= HS / 4) in which 6 is the root mean square wave height (where 

HS is the significant wave height), and CP (= g Tp / 27r) is the phase speed of the waves at the spectral 

peak (where TP is the wave period at the spectral peak and g is the gravitational acceleration). Since 

154 
CP / U ,o is defined as the wave age, Zo is then directly proportional to HS and inversely proportional 

to the 2.6 power of the wave age. In other words, for a given HS and U,o, Zo is larger for younger 

seas (i .e ., smaller magnitude of CP / U,o or shorter wave period) and smaller for older seas (larger 

CP / U,o or longer wave period). 

From Eqs. (1) and (3) and by setting Z = 10 m and x = 0.4, one gets 

0 .4 U10 

u = 

11 .0 - In 

H

S (4) C 2 .6 

P 

U10 

Therefore, we can estimate u, from the wind, U,o, and wave (HS and CP) information. Eq. (4) is 

referred to here as the wind-wave interaction method. Also, Cd may be obtained from this equation 

and Eq. (2) so that 

0.4 

Cd H 

11 .0 - In S 

C. 2 .6 (5) 

P 

U10 

This is our recommended operational formula in which all parameters are routinely available from 

most data buoys. Verifications of Eqs. (4) and (5) in the Gulf of Mexico are provided in Hsu 

(1995a). It is shown that the agreement between these equations and the Cd formulation suggested 

by Wu (1982) and the WAMDI Group (1988) is within 95% such that 

Cd = 1 .2875 x 10-3 Ulo < 7.5 m/s 

_ (0.8 + 0.065 Ulo ) x 10-3 Ulo >_ 7 .5 m/s 

Since wave characteristics were not recorded at the Breton Island station, Eq. (6) is employed for 

determination of all drag coefficients in this analysis . 

d. Atmospheric Turbulence 

For pollution dispersion studies, atmospheric turbulence intensities in the horizontal and 

vertical directions are used. They are defined as (see, e.g ., Zannetti, 1990) 

6 = 6,, t Sy t (7) 

TL 

C Z = 6 x, 1 S 

TL 

155 
where 6, and 6W are the standard deviations of the crosswind and vertical wind vector components, 

and Sy and SZ are universal functions of the diffusion (or travel) time t and the Lagrangian time scale 

TL. Functions of Sy and SZ are provided in Zannetti (1990) . 

If we convert t to the downwind distance x with the wind speed U, we have 

ay = U ° x Sy T(9) 

io t 

= a'" x S 

Uio Z Ti 

(10) 

For overwater applications, the turbulence intensities are found to be (Geernaert et al ., 1987) 

6 

'' = 0.0586 + 0 .0012 U10 ± 0.015 (11) 

U10 

and 

6 

' = 0.0369 + 0.0010 U10 ± 0.005 

Uto 

Because av and aW also vary with the atmospheric stability, we need the stability 

classification. Commonly, the Pasquill's Stability Classification scheme is employed (see, e.g ., 

Panofsky and Dutton, 1984). For offshore regions, this classification may be obtained through the 

parameterization of Hsu (1992) that 

3 

Z = x CT Cd 2 Rb (13) 

L 

and 

gZ~T r. - Tea 

b Ulo ~ T ea + 273 

where Z is the height above the sea surface (normally set to 10 m), L is the Monin-Obukhov length, 

x (= 0.4) is the von Karman constant, CT is the heat flux coefficient, Cd is the wind-stress drag 

coefficient, Rb is the bulk Richardson number, g (9 .8 m s-Z) is the gravitational acceleration, Tai, and 

Tsea are air and sea-surface temperatures in °C, and U,o (m s-') is the wind speed at 10 m height . 

In Eq. (13), the heat flux coefficient, CT, does not depend strongly on the wind speed, but 

is larger in unstable (CT = 1 .10 x 10-3) than in stable (CT = 0.83 x 10-3) conditions (Smith, 1980) . 

Garratt (1992, p. 102) suggests that under near-neutral conditions and for winds up to 25 m s-" CT 

= 1 .1 x 10-3 (f 15%). 

156 
e. Vertical Mixing 

Vertical mixing includes eddy diffusivity and the mixing height . 

The Vertical Eddy Diffusivity 

In some K-diffusion models, the vertical eddy diffusivity, KZ, is required, e.g . (Hanna, 1984) 

K = c u, Z 1 - h (15) 

where u, is the shear velocity defined above and h is the mixing height . For example, the Urban 

Airshed Model (UAM), the preferred model of the EPA for ozone studies, has a meteorological 

preprocessing subroutine which employs the gradient transport (K) modeling (Zannetti, 1990, p. 

234). Since in the K-theory, u. is required for the computation of vertical diffusivity, KZ, and 

concentration, x, it is recommended that proper formulas to reflect the overwater variations in 

aerodynamic roughness length Zo, or the drag coefficient Cd, be made in light of recent advances in 

the air-sea interaction field as shown in Eq. (5). 

Note that if proper Cd values (103Cd = 1 .090 + 0.094 U,o) (obtained by buoy 42035 near 

Galveston, Texas using Eq. (5)) for the shallow water environment (such as Galveston Bay) are 

compared to those for the open Gulf of Mexico (103Cd =1 .14 based on open ocean conditions (Large 

and Pond, 1981) when U 1o ranges between 4 to 11 m s-'), the ratio of KZBay / KZcuie as well as Hbay / 

Hgulf 1S 1 .18 when Uio = 5 m s-1 . This ratio increases to 1 .32 when U1o increases to 10 m s-' . On the 

other hand, the ratio of concentration (,Bay / xcuie is 0 .85 and 0.76 when U,o is 5 and 10 m s-1, 

respectively . 

2. The Mixing Height 

Due to potential evaporation, the air over the water is usually moister than that over land, 

and the top of the marine boundary layer is oftentimes capped by clouds (see, e.g ., Garratt, 1992). 

On the basis of analysis of vertical soundings by research aircraft, rawinsondings, and radar wind 

profilers and Radio Acoustic Sounding Systems (BASS), it has been shown by Garratt (1992) that 

the mixing height h = LCL, the lifting condensation level under cumulus cloud conditions (where 

LCL = cloud base). The height of the LCL may be estimated by (see McIlveen, 1986, p. 126) 

H eo = 125 (T J, - Td,,, ) 

where Hsea is the mixing height over the water surface, and Ta;r and Td," are the air and dewpoint 

temperatures (both in °C) over the water, respectively . However, if the clouds are stratiform (as is 

often the case over the U.S . west coast), the height of the cloud top rather than base is the mixing 

height (Garratt, 1992, p . 205). A method to obtain Hsea by using NOAA series or GOES satellite 

detection of cloud top temperature is shown in Fig. 78. Note that one may follow the saturation 

adiabat from the cloud top temperature downward and follow the dry adiabat from the surface air 

temperature upward . The point of intersection is the LCL. In this procedure, the height 

corresponding to the cloud top temperature must be determined beforehand from nearby routine 

rawinsonding station. If multi-layered stratus cloud, mid-level, or cirrus clouds are present, the 

157 
warmest cloud-top temperature (CTT), which represents the clouds in the lowest layer, will be 

applied. Because the sea-surface temperature can be determined in the cloud-free region, the CTT 

in the first cloud layer away from the sea surface can be identified by the nephanalysis (see, e.g ., 

Kidder and Vonder Haar, 1995) . 

Cloud top temperature from satellite IR 

LFC 

- - - - - Level of free convection 

Saturation adiabat 

Clouds 

t ~ 

Height 

LCL _ Cloud base 

Mixing 

height 

Tdew\. 

i 

a 

F 

- - - -Lifting condenstation level 

Tdry p~~ from buoy or ship 

'All, 

Temperature, T ), 

Figure 78 . Determining overwater mixing height from the dewpoint depression 

at the surface or from surface and cloud-top temperatures based on 

atmospheric thermodynamics (see text for explanation) . 

Alternately, if we know the mixing height on land, H,ana (in meters), and a barotropic 

boundary layer across the coastal zone exists, we may estimate the mixing height over the water, 

Hsea (in meters) by applying (Hsu, 1988, p. 183) 

z 

Cd sea Uses 

ea - Hland 

Cd land Uland 

where Ca,.a is the drag coefficient over land, Cdsea is based on Eq. (5), Us,a and U,ana (both in m s-') 

are the windspeeds at sea and over land, respectively . 

Dry adiabat 

158 
If the planetary boundary layer is baroclinic across the coastal zone, i .e ., under land and sea 

breeze effects, according to Hsu (1988, p. 204), 

H ea - Hland - 123 (Tram - T ea 

where T,and and Ts,a (both in °C) are the air temperatures over land and sea, respectively . 

2. Use of Observations to Compare Methods that Evaluate Parameters Associated with Key 

Processes 

a. Determining Z/L 

Hourly values of Z/L were calculated for NOAA buoys 42007 and 42040 and C-MAN 

GDIL 1 (Grand Isle, Louisiana, see Fig. 79 for locations) as well as at Breton using Eqs . (6), (14), 

and (13) and setting C,. = 1 .1 x 10-3 . On first examination, stability was classified as unstable for 

Z/L < -0.03, neutral for jZ/Lj < 0.03, and stable for Z/L > 0 .03 . Figure 80 shows the frequency of 

occurrence for each category. Breton Island stability characteristics most closely resemble those 

at buoy 42007 ; therefore this station's long-term record may be used to approximate conditions over 

the BNWA. 

Investigation of the seasonal variations of meteorological and stability parameters over the 

study area was performed to further define their spatial and temporal characteristics . Monthly mean 

and standard deviation of Breton Island air and water temperatures are compared to the mean values 

at buoys 42007 and 42040 in Figure 81 . Excellent agreement in air temperature amongst the three 

stations occurs throughout the year. As expected, sea surface temperatures at Breton and 42007 are 

well correlated, however wintertime (November - February) sea temperatures at buoy 42040 are 

considerably higher (4 - 6°C). From Eqs. (13) and (14), it can be inferred that this most offshore 

location is more unstable, as verified by Fig. 80 . Note that the water temperature sensor at Breton 

was located in shallow water at the end of a concrete pier extending from the Kerr-McGee facility . 

Diurnal and seasonal heating and chilling of this shallow water body is likely more pronounced at 

this location than at the open-water buoys . 

159 
Mississippi 

w" ~ A 

. . 20 71 x 

=~ t ~ c 

a=, 

r s' 

' '~ 42t~0 ~f 

\ . Z 1 

_ _,y, A i -G t . 

a 

Figure 79. Approximate locations of 

NOAA buoys and C-MAN 

stations used in this analysis . 

Unstable 

Neutral 

Stable 

Figure 80 . 

Stability Characteristics 

May 1997 Through July 1998 

. Breton hind (75% Complete) 

GDILl (95.5% Complete) 

Buoy 42007 (77.9% Complete) 

Buoy 42040 (93.1% Complete) 

0 10 20 30 40 50 60 70 80 90 100 

Occurrence 

Frequency of occurrence of stability classes for three NOAA stations and Breton 

Island during the period of May 1997 through July 1998. 

160 
Monthly statistics of computed Z/L at all three offshore stations resulted in unrealistically 

large negative (unstable) mean values . This was found to be caused by a relatively small number 

of free convective cases (Stability Class B, Z/L < -1 .0). A nomogram developed by Hsu (1992) to 

obtain Stability Class from routine measurements available at sea (Figure 82, proposed for use in 

air quality modeling, such as the OCS model (Hanna et al ., 1985, Hsu, 1992)) was employed to 

identify hourly records which fell into Classes B and F . These records were then removed, since 

Monin-Obukhov theory is not applicable beyond ~Z/Lj > 1 (see, e.g, Kaimal and Finnigan, 1994) ; 

and monthly statistics were re-computed . Figure 83 depicts these results . Unstable (Z/L < 0) 

conditions exist at all locations throughout the year. Mean stability approaches free convective 

during the summer months, with Class B observed approximately 10 - 20% of the time (greater 

frequency at 42040). During the winter season, 42007 and Breton become more near-neutral, buoy 

42040 responds much slower due to the abundant supply of warmer water further offshore . Again, 

the trend toward more stable conditions at Breton in the fall may be partially due to the chilling of 

the shallow waters. 

A more convenient method for obtaining Z/L from readily available measurements is 

described as follows based on a comparative analysis of Z/L and Rb using data provided in Donelan 

et al . (1997) . Parameters given in Donelan's extensive data set included U,oN, Tav TSw L, and u.. 

By setting Z = 10 m, the stability parameter Z/L was obtained. 

For the first run, all records with Z/L < 0 were retained for a total of 96 samples . The bulk 

Richardson number, Rb, was given by Eq. (14). Values of Z/L extended to about -8, with 8 points 

being < -3. For these points, UIoN was _<5 m s-', and Ta;r - Tsea z-8°C. These values were obtained 

under light wind conditions blowing almost directly against the 2 - 2.5 m swell following a cold 

frontal passage. This is extremely unstable, and therefore Monin-Obukhov theory does not apply. 

Thus, these 8 records were removed from the analysis. 

From Eq . (13) and for Z/L < 0, Rb must be < 0. However, three points occurred where Rb 

> 0 and Z/L < 0. These values were recorded following the passage of another cold front, when Ta;r 

was still slightly warmer than Ts,a and the winds brisk. These stability values approach near-neutral 

conditions (IZ/Ll < 0.03) and were also excluded. 

85 samples remained comprising Stablility Classes C and D (for Z/L < 0). For all samples, 

Z/L = 12 .41 Rb with a correlation coefficient of 0.9 . If only stability class D (-0.4 < Z/L < -0.03) 

is considered, 63 samples gives Z/L = 11 .77 Rb with correlation of 0 .93 . Good fit is also obtained 

for Class D stable (Z/L > 0), however note that several points included in this regression fall into 

the near-neutral category. These results are summarized in Fig. 84. For those wind speed 

measurements taken a 5 m on NDBC buoys, correction to 10 m can be based on Hsu (1988, Table 

8.5, p. 202). 

b. Turbulence Intensity 

Turbulence intensities derived from measurements of u, v, and w wind components under 

near-neutral conditions (IZ/Ll < 1 .0) at Breton Island were compared to the relationship found for 

the North Sea (Geernaert et al ., 1987) (Eqs. (11) and (12)). Data observed under light wind 

161 
conditions (U,o < 5 m s-') were excluded to ensure representation of stability class D conditions (see, 

e.g ., Zannetti, 1990) . In Fig. 85, good agreement is found for downwind (6u) and vertical (6w) 

intensities ; however larger crosswind (av) intensities are observed at Breton . As described 

previously, this may be partially due to topographical effects as well as the influence of man-made 

structures . Since the uvw sensor was fixed in the standard u = 90° (east), v = 360° (north) 

orientation, the dataset was narrowed down to only winds parallel to these directions for better 

delineation of the lateral variances . Closer agreement is achieved, as shown in Fig. 86. Note that 

westerly winds were excluded due to the presence of large structures in this direction. Further 

defining these relationships is essential for proper 6y and 6Z calculations in dispersion modelling 

efforts over the BNWA. 

162 
35 

30 

L 

25 

a 

E 

L 20 

Q 

e 

R 

15 

s 

0 

10 

5 

35 

0 30 

0 

25 

F-ca 

20 

s 

c 

~°, 15 

10 

Figure 81 . Monthly statistics of air and water temperatures at Breton Island and two 

NOAA buoys. Vertical lines are standard deviation at Breton. 

163 

Mav Jun Jul Aug Set) Oct Nov Dec Jan Feb Mar Aur Mav 

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May 

1997 1998 
12 

11 

10 

9 

s 

h 

E 0 

rl 

5 

4 

3 

2 

i 

0 

a 

r 

D 

Near Neutral 

E 

o 

`o ~y 

C 

j0 

F 

Strongly Stable 

Free Convective 

-10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 

Tair - Tsea 

Figure 82 . The stability classes as a function of wind speed and air-sea temperature 

difference (from Hsu, 1992) . 

164 
0.4 

0.3 

0.2 

0 .1 

,~ 0.0 

-0 .1 

-0 .2 

-0 .3 a 0 

-0 .4 

-0 .5 

-0 .6 

-0 .7 

-0 .8 

6/97 7/97 8/97 9/97 10/9711/9712/97 1/98 2/98 3/98 4198 5/98 

20 

18 

16 

14 

a 12 

c 

U 10 

L 

w 

0 

4 

2 

0 

Figure 83. Monthly statistics of stability characteristics and frequency of occurrence of 

free convective conditions at Breton Island and two NOAA buoys. Vertical 

lines are standard deviation at Breton . 

165 

6/97 7/97 8/97 9/97 10/9711/9712/97 1/98 2/98 3/98 4/98 5/98 

Month 
v 

0 

0 

N 

O 

rr 

0 

O 

O 

0 

NlV 

4 

0 

4 

4 

4 

00 

c 

.; 

i 

Donelan et a1.,1997 

s 

. 

For 0.01 S Z/L S 0.28 

. . ~ ~ . 7JL=5.6Rb 

For-0.72 S Z/L S -0.03 

~ 7JL=12.41Rb 

." ; 

. : . 

i 

0.06 -0.05 -0.04 -0 .03 -0.02 -0.01 0. 00 0.01 0.02 0.03 0.04 0.05 0.( 6 

Rb 

Figure 84. A relationship between Z/L and the bulk Richardson number, Rb, based on 

measurements from a continental shelf environment by Donelan et al . (1997) . 

166 
0.8 

0.7 

0.6 

6 u 0.5 

U10 0.4 

0.3 

0.2 

0.1 

0.0 

1.0 

0.8 

6v 0.6 

oho 0.4 

0 .2 

0.0 

0.2 

C'° =0.0015U,0+0.0851 

U10 

s 

C'V = 0.0037 U 10 + 0.0668 

Uio 

_-__ 6N' = 0.0007 U to + 0.0335 

Uio 

T k1w. ". -.-Li6W 

Uio 0.1 

0.0 -t 

4 

Figure 85 

8 12 16 1 20 24 28 

U1o+m S - 

Observed turbulence intensities at Breton Island compared to the relationship found for the North 

Sea (denoted by solid line from Geernaert et al ., 1987). 
00 

0.6 

0.5 

0.4 

6v 

0.3 

Uio 

0.2 

o. 

o. 

4 

Breton Island Turbulence Data 

j7JLj < 1 .0 

Direction= 90, 180,360 +/-20 ° 

1995 Samples 

I v V = 0.0008 U10 + 0.0668 

Uio 

Geernaert 

00 

8 12 16 

Uio m s-1 

20 24 28 

Figure 86. Lateral (crosswind) turbulence intensities at Breton Island compared to the relationship for the North Sea 

(see text for explanation) . 
c . The Mixing Height 

New satellite systems scheduled to come online will provide accurate measurements of 

surface and cloud-top temperatures as well as heights of the cloud tops. Figure 87 shows an 

example for determining the mixed height from remotely-sensed data as described in Section 

III.D. I .e .2 . and Figure 78. The computed LCL, or mixed height, from a radiosonde profile recorded 

at Breton Island on 4 August 1998 is shown to be in excellent agreement with that obtained from 

the satellite data. 

While the Breton Island air quality station was being removed on 3 - 4 August 1998, several 

radiosondes were launched from the moored camp Chandeleur Islander nearby . Figures 88 through 

96 display the standard Skew-T log P thermodynamic profiles for each launch, along with boundary 

layer profiles of potential temperature (8), virtual potential temperature (6v), and mixing ratio (q) . 

The latter profiles were used to estimate the mixing height as that point at which the lapse rate of 

both A and q change abruptly (see, e.g ., Hsu, 1988) . 

As discussed previously (Sec . III .D.l .e .2 .), the mixed height over the marine environment 

may be equivalent to the lifting condensation level (LCL) . Figure 97 shows a one-to-one 

comparison of LCL heights obtained through Skew-T analysis of the Breton radiosondes versus 

mixed heights calculated by Eq. (16) and estimated from boundary-layer profile. Root mean square 

errors for both methods are within 90 m; the error obtained from Eq. (16) is less than 20 m. Thus, 

Eq. (16) is recommended for operational use. 

To visualize seasonal variations of the mixing height over the southeast Louisiana coast and 

eastward over the BNWA, Eq. (16) is applied to the records of C-MAN stations GDIL 1 and BURL 1, 

NOAA buoy 42040, and Breton Island . Dewpoint temperatures are recorded at the first three 

stations, for Breton dewpoints were calculated from air temperature and relative humidity by 

2302x7.5xTa;, 

E 6.1078 x e 

2373 - Tai, ) 

s 

E = 

1~ ES 

(20) 

(237.2 x Q ) where Q = loglo E (21) 

(7.5 - Q) 6.1078 

where E and ES are the vapor pressure and saturation vapor pressure over water, respectivey; RH is 

the relative humidty; and Tai, is the air temperature. Eq. (21) is valid for wet-bulb temperatures 

greater than zero. Since this parameter was not recorded, monthly minimum values of air 

temperature and relative humidity were input into psychometric tables ; in no case was the 

corresponding wet-bulb temperature less than zero. 

Figure 98 shows our results. Mean mixed heights range from about 250 m to 750 m, with 

peaks in August and April. Excellent agreement is found between Breton and GDIL1, while both 

BURL I and 42040 generally are much lower. It is interesting to find the low mean heights at 

169 
BURL 1 and 42040 from January through May 1998 . A possible explanation may be localized 

effects caused by the discharge of cold Mississippi River water. 

High concentrations of pollutants may be anticipated if a release were to occur during very 

stable conditions offshore . Stable mixed height may be approximated by (Panofsky and Dutton, 

1984) 

u, L 

22 hsrabie = 0 .4 

where f = 2S2sincp . From Hsu (1998), when Tai, > Tsea stable), 

3 

L = - u * Cp P T r. (23) 

xgH 

where HS (sensible heat flux) = PCPCT(Tsea - Tair)UIp . Substituting back into Eq. (22) and reducing 

air 

hsravre = 0 .4 Cd Ulo ( ) 

f K g CT (T it - T ea ) U10 

Employing the WAMDI (1988) formulation for Cd (Eq . (6)), Figure 99 shows that an estimated 

mixed height of only 104 m was found under an episode of stable conditions at buoy 42007 . 

When the atmosphere is unstable, i .e ., when Tsea > Tair, the formula proposed by Hsu (1997) 

may be applied that 

Z~ = 369 + 6004 ( W /0V )0 (25) 

The Offshore and Coastal Dispersion (OCD) model proposed and evaluated by Hanna et al 

(1985) requires the Monin-Obukhov length to compute the stability class . Both wind shear and heat 

flux are needed for this computation. The previous discussions have presented several methods for 

estimating these parameters and others over the BNWA. According to Chang et al. (1998 - see 

MMS 98-0050), these newer parameterizations need to be further tested. 

170 
" . 

~ft R . 

SBB 

( .1.) 

600 

700 

800 

900 

1000 

1050 

<°C) 

a 

is 

4 

loud-top: 

LFC. . . . . . . .

:-'--'-- . .. . . . . . . . . . .

. . . . . .

.

. . . .. 

. . . . . . . . . .5_ Temper e 

LL I . . . . . .

.---

. . . . . . . . . . . . . . . . . . . ... . . . . . . . . . ., . . . .. . . . . : . . . . . . . . 

Zif

.

t - 

" 10 I 0 0 2d 30 40 

10 -iF J 

f I 

1 

Figure 87. A demonstration of LCL (mixed height) from cloud-top temperature using data 

obtained over Breton Island on 4 August, 1998 at approximately 1500 GMT (1000 

LT). 

171 
RROB . ., ; i . u .- , . . . . ., . . . . . i 300 STN 

Cnb) ,`+ +tPF 

ccl-El 

1fcLFC 

LCL 

H 

X\ T= I 

400 _ S 

a 

500 . 

600 

. ._, ., . . . . / 

700 

K FT -KM 

-9 

-8 

25 

--7 

I 20 -- 

6 

I -5 

15 

I -4 

10 ._ ..1 

800 / ' 5 -

900 

1000 

~" -0 

105 0 

(°C) -2 -10 0 1 20 30 40 Knots 

lin~~r9, Sn.kg 

15 16 17 18 19 20 21 22 23 

i 

^8 

i 

i 

i i i i 

5 cP 

1 

1 

1 

1 

1 

j- ~7C ~ ~p 

1 

1 

1 

1 

1 

1 

ProNe : R1080316 

0 

m 

LEV : 7 ft MSL 

CIP : AuNO 

HGT : 1374 ft RGL 

HGT : 2817 ft RGL 

HGT " 1151 ft RGL 

TER: 2.41 in/ 

AIL: 0.25 in 

UST : 33 kt 

DEX: 51 kt 

ERT : 

CRP : 0 .3 / 

LI : -2 .2 

rr : 

/x- I

: --

Tc : 30 .8 °C 

StorM: ~ kM I 

s-rN : -- 0-3kM 

-s-rH : -- 0-2kM 

1 

CAPE 

CAPE*: 

; -- J%kg 

(- -- J/kg ' 

MVV: -- M/s 

BRN: -- 

HI : -- ' 

y ase 

LPLB1015nb 

26 27 28 29 30 31 32 33 3 

B . B . °C 

Figure 88 . Thermodynamic and boundary layer profiles of 3 August 1998, 1619 CDT 

radiosonde over Breton Island . "-line is 8, X-line is q, dashed line is 9v . 

172 
RROB i :8 t t i :, ' if t ; 

300 X". ;~ ST 

ccl-

(Mb) 

lfcL 

400 

500 

6 00 . _ . ., . .. . . . . . . . / as e 

~ DryJ B TenP 

LPL 1013nb 

700 

c I 

800 I 

900 

i e 

: : 

M 

1 5 . 

C°C) 2 -10 B 1 20 30 40 

I. .-nn-J, T-+, 

9" Srtlkg 

11 15 16 17 

IS 

19 20 21 

ELEV : 7 Ft MSL 

LOUD AUTO 

RECIP : NO 

L HGT: 18000 ft AGL 

L HGT: -- ft ACL 

C HGT: 1775 ft AGL 

L HGT: 3786 ft AGL 

L HGT: 1741 Ft RGL 

HATER: 2.12 in/ 

HAIL : 0.23 in 

zGIIST : 35 kt 

INDEX : 45 kt 

SWERT : 

CLAP

: -0-9 / 

TT : 

I : 

Tc : 32 .0 °C 

Storm : 

s-rH : 0-3hM k" 

s-rH : -- 0-2kM 

,~ CAPE + ; -- J//kg 

ICAMVV : -- n%sg 

BRN : --

HI : 

i 

i 

i 

1 Op 

I 

1 

1 

i 

1 

~]( i ^C~ 

1 

' ' V 1 

i 

58 

i 

i 

1~ 'I 

Y 

Y 

v 

ProNe: RIOR0318 ~ 

0 

27 28 29 30 31 32 33 34 

0,0"C 

H -FT =9 KM 

25 

-7 

20 - _ 

6 

15 

I 10 - -3 

=2 

5 

-1 i 

-0 

Knots 

Figure 89. Thermodynamic and boundary layer profiles of 3 August 1998, 1804 CDT 

radiosonde over Breton Island . Lines as in Fig. 88 . 

173 
RROB , .~ . ,~ i~ . , . . ., . i _~ . . . 

300 S 

CMb) 

ccl 

400 

t 

500 

600 

. ,`` 

J 

700 ' 

ELEV " 7 ft MSL 

LOUD AUTO / 

RECIP : NO 

L HGT " -- ft AGL 

L HGT' - ft AGL 

C HGT' 1097 ft AGL 

L HGT : 3696 ft RGL 

L HGT : 1097 Ft RGL 

WATER: 1.60 in 

zGl1ST' 36 kt 

INDEX' 47 kt 

SWEAT' 

'CAP

: B.0 

/ LI : -2 .9 

/ Ti : --

HI : 

Tc : 29 .0 -C 

S : .k'Hm : -- 0-3kkmm -~-VH : __ 0-2km 

IC/APE+ : J/kg 

` 

APE- : 

BRN : --

c 

M"" : 

', EH I : -- --

AL, ase 

yJ II Tent' 

PL 1014nh _ 

00 '

. . / 1 

J~l~ 

~~rl S. 900 i 

1000 ~, ` 

105 0 

(°C) -2 -J L 0 10 2 30 40 

9. g.V4 

9 10 11 12 13 

14 

15 16 17 IS 19 

I 

K 1 

J 1 q 

i 

i ~cP 

i i 

i ^cP 

ProNe: B1080320 b~ 

E 

i 

W 

0 

23 24 25 26 27 28 29 30 31 32 

e,e .°c 

K -FT -KM 

-9 

25 

_, 

20- 

f 

I `i 

I 15 

--4 

I le -' 

1 

Knots 

Figure 90. Thermodynamic and boundary layer profiles of 3 August 1998, 2002 CDT 

radiosonde over Breton Island . Lines as in Fig. 88. 

174 
RA OB . . . ._ . . ~i . . . _ ., . . . . . , . , .i, 

500 STN ELEU : 7 ft MS 

Cnlo) ~ ~PRECIP: AuNO I ccl-EL HGT : -- ft AGL 

lfc-EL HGT : -- Ft AGL 

. LFC HGT : 5234 Ft AGL 

CL HGT : 6121 ft AGL . . . . . . . ' LCL HGT : 1698 ft RGL 

WHAIL: 

2 .16 

WINDEX : 36 kt 41EAT : -- -----{((-- 600 CRPL : 2 .1 J 

1 : 

T T : -- 

K -FT -KM 

-5 

15 - _ 

. . . . . ., . . . . K I : - - I 

To : 36 .3 C 

S ~ .: km 

'~ : 

S 'H

: 0-3km 

s-Z.H : 0_2km 

780 f APE+ : J/kg 10 - I CAPE- : 

V : -- M%sg 

- 

( BRN : 

/J t ~ ~ ' LFC Based Dr B Ter~ 

- 

p 

y P 

LFL 016n1, - _ 

f 

I 

800 r l I 

- 

- 

s 

900 -1 

1000 

105 0 

<°C) -10 0 0 20 30 40 0 Knots 

q, g-/kg 

12 13 14 15 16 17 18 19 20 

Ile 

i 

I q~ 

1 

1 

I 

1 

i 

E 

~Q s 

i i 

i 

i 

i 

i 

tidy 

i Yroflle: H1080322 i i 

i 

i 

0 

27 28 29 30 31 32 33 31 

a . e . °c. 

Figure 91 . Thermodynamic and boundary layer profiles of 3 August 1998, 2157 CDT 

radiosonde over Breton Island . Lines as in Fig. 88 . 

175 
RAOB [m 

500 :, / ST 

CMb) 

ccl-

.` L 

il 

1FCL 

i 

t baa 

. . .l 

700 

800 

900 

1800 

S 

'ELEV : ~ 7 Ft MSL H -FT -HM 

RECIP puNO 

' 

: 

C HCi : 1741 ft R G I -5 

L HCT " 2621 ft RGL 

L HGi' 852 ft AGL 

WATER : 

: in k 15 - 

zGl1ST : 35 kt 

INDEX : 4? kt 

SWEAT : 

C LI : 0 = s ~ -4 

TT : - 

HI : 

To : 29 .6 C 

St01+M: I ~(M . 

s-rH : -- 0-3kM 

s-rH : -- 0-2kM 

APE+ ; ~ -- J/kg'. 10 

CAPE- : -- J/kg' 3 

MUV : -- M/s - 

BRN : -- 

LFC 

Dry B 

LPL 

I 

Base ' 

Temp 

1014nh 

r. J 

(oc) -18 a lo 20 3e ~ 

Lani~,l, fines 

40 

N`,4 l ':I'[ : C~~~tr71 

9" g-kg 

15 16 17 18 19 20 2 

qC~ 

i 

i 

1 

1 6~ 

i JC 

4 ~ cP 

i 

'V I b~ 

i 

v l 

. ,~ 

r ,, 

ProNe: BIUSU4IM i 

i 

0 

26 27 28 29 30 31 

0, 0 .T 

E 

s 

s 

1 

Knots 

Figure 92. Thermodynamic and boundary layer profiles of 4 August 1998, 0541 CDT 

radiosonde over Breton Island . Lines as in Fig. 88. 

176 
RROB 1<ro4~,:, , H 'I ; i,~ i , i ~, i .~ 

500 STN 

CL 

CMb) ~~ SPA 

eel-EL 

1fcLFC 

+, ~CCL 

~LCW 

~J T z 

600 

700 

800 

:V' ~ 7 ft MSY. K-FT - - HM 

~S : AUTO 1 

P : NO l 

T : 1611 ft A GL -5 

tT : 2399 ft AGL 

T : .1~49 ft AGL 

M: 2 

34 n/ 

L : -- in 15 

T : 35 kt 

I X: 48 kt 

T : 

P: 

I : T : 

:- - 

I : 

- 

- 

0 : 2 . z C 

on" : 

-nH : -_ G-31k . 

rH : 0-2km 

-CA PE+ : J/k' 10 - 

CAPE- : -- J/kg . -3 

MUV : -- n/s - 

l 

BRN: -- / 

LFCB ase d 

Dry B Temp 

LP 1019.), 

' 

. 

' ;

, 

( 

5 

900 

~a0a I 1 1 1 1 

e ~e~e II O 1 1 ~ ICI Z 1, i 3I ~ I 4I , 

I .+~~ncl, TRH N:tN2 _IVC . ;( .( . l- Cr-, -n-- .C, : Itl{N s[-r ~ . ., . -l .~ 

9. g-/kg 

16 17 18 19 20 21 

0 

i 

i 

i 

i 

I 1 

`][ 

I 1 

I 

I 

i E 

y~ z 

i i -

i i 

w~ ,~cP 

r 

NS, i 

ProNe: R1080408 i i 

i 

%-~ 

x o 

26 27 28 29 30 31 32 33 

e,e~°c 

Hnots 

Figure 93 . Thermodynamic and boundary layer profiles of 4 August 1998, 0802 CDT 

radiosonde over Breton Island . Lines as in Fig. 88. 

177 
RAOH ; ; ; :It k1 . . ., . . i . . 

400 S 

Cnb) 

ccl 

lfc 

~'r r 

z 500 "', ., 

Z' 

. 

600 ~ . 

700 

SBB 

' . . 

-`~S 

ELEV : 7 f t MSL K - FT - H 

L04DS : AUTO -7 

RECIP: NO 

/ 

L HGT : -- ft AGL L HGT : -- ft RGL 

C HGT : 8808 ft AGL - 

L HGT : 2988 ft RCL - L HGT : 1191 ft AGL WATER: 2 .57 in I 20 

z C A I IST : 033 kt INDEX: 48 kt - SWEAT : -- 

CAP: 0.9 - 

LI : -0.1 

TT : -- 

' 

HI : -- -5 

To : 32 .2 °C 

I 

SLOIPM : km LS - s-rH : -- 0-3kM - 

___s-rHH : -- a- 2k

. 

/ - 

CAPE+ : ~- J/kg -4 

AMU 

I 

V : -- n%sg - BRN : -- - 

".. EH I : -- ' - 

L^C Based 

MB 0 b 

10 - 3 

1 15n ' = 

gee 

lose Z 

iesa 

(°C) -10 0 0 20 30 40 0 

I. .-~~111~'.1~ LtM~' I .N4141 (.I'~ : IiICM 1C2 .+t~l~l~M~~I~I  ei1Ml1I~ .~ . ~,Jn~ ~lt~ ., I :IM) .~~. 

9, HmlkK 

IB 19 20 21 22 

-T 

i 

Z`,,,,, ' 

i 

1 

1 

i 5cP 

i 

i 

1 

1 ~ 

I' J~ ,y~ 

1 

1 

1 

ProNe : BI080.110 

I 

I 

O 

26 27 28 29 30 J1 32 JJ J4 3 

B~Bv°C 

E 

m 

-2 

5 

1 

=e 

Hnots 

Figure 94. Thermodynamic and boundary layer profiles of 4 August 1998, 1000 CDT 

radiosonde over Breton Island . Lines as in Fig. 88 . 

178 
RAOB 

500 ST 

(Mb) 

ccllfcz 

600 

700 

800 + 

4 

900 

7 f t MSL E FT - - EM 

AUTO 

NO 

-- f t A I L 

- ft AGL 1838 ft AGL -5 

3024 ft AGL 853 Ft AGL 

1 .92 

i n 15 - 

-- kt 

-- ~k-t 

0.3 ~ - 

-4 

31 .3 °C 

J 

ACM 

-- 0-3kM 

0-2kM 

E+ : ~ -- J/kg LH - 

E- : -- J/lcg ~ - 3 

UV : -- n/s 

RN : -- l " - 

HI : -- 

LFC Bas e I 

DryB Temp 

LPL 1016, 3~ 

-2 

I 

-1 

1000 

.. -0 

105 0 

C°C) -10 0 10 20 30 40 50 Knots 

I .~uI1~tI, I IM " I :' I 7 ',I!I . ViICN I, .~.I 111 . ~ 

9. KnVkg 

16 17 is 19 20 21 22 

i 

i 

i ~cP i i 

v 

i 

b I 

i 

- r 

'V 1 

u I 

x 

1 

1 

1 

1 

1 

ProNe: 81080412 ~ 

0 

Figure 95 

26 27 28 29 30 31 32 33 34 

0,8~'c 

L 

Thermodynamic and boundary layer profiles of 4 August 1998, 1217 CDT 

radiosonde over Breton Island . Lines as in Fig . 88 . 

179 
RAOD 

500 S F -T- 7\ CCI 

. . . . . . . . . . . . . . 

LH 

B 

110176"""b 

L n -2 

- 

5 

L 

900 -1 

t 

1000 s ~ 1 - 

-0 

1050 (°C) -10 0 B 20 30 40 0 Hnots 

I . ,.~ncl~ '( . n. I4i', iYC : .r1 iti!N 

9. gnlk8 

15 16 17 18 19 20 21 22 23 

ELEV : 7 f t MSL H - FT- -]<M 

LOl1DS : AUTO - 

RECIP: NO 

I 

16495 

L HCT ~ ft RGL 

C HCT : 3220 ft RGL ~ -5 

L HGT : 5853 ft pGL ~ WATER : 2 .40 in/ 

HAIL : -- in 15 - 

NDEX 31 

I 

I : kt - 

SWEAT : -- ~--- ~~--~- _ 

CAP: 

B 5 

/ ~ 

- -4 

TT : -- 

' 

- 

HI : 

I 

Tc : 35 .7 °C - 

S t onM" ~ kM ' - 

s-rH : -- B-3kM s-rH : -- 0-2kM 

APE+ : ~ -- J/kg I 10 - - 

CAPE- : -- J/kg ' 3 

MVV : -- n/s - 

BRN : 

I 

/ " EH I : J - 

LFC 

~ -~ 

Based I 

t 

i 

i 

i ^cP 

i 

I 

i E 

i 

1 ti~ 

s 

I 

I 

I 

1 

1 

1 

1 

Profile : B1080414 , 

t 

t 

0 

27 28 29 30 31 32 33 31 35 

e,e.°c 

Figure 96. Thermodynamic and boundary layer profiles of 4 August 1998, 1415 CDT 

radiosonde over Breton Island . Lines as in Fig. 88. 

180 
600 

500 

T 

550 

'i' 

"i" 

450 

400 

350 

s 

on 

x 300 

250 

200 

150 

100 

50 

0 

fit 

i' 

'i' 

'3 Points 

Breton Island Radiosondes 

" MH = 125 (T alr - T dew) 

RMSE = 17 m 

MH (from Profile) 

RMSE = 87 m 

V JV 1VV 1JV IyVV IyJV JVV Wv -vv -.iv .iv v --v --- 

Lifting Condensation Level, m (from Skew-T Analysis) 

Figure 97. One-to-one comparison of LCL heights versus mixed heights from profile and 

computed by Eq. (16) . 

181 
00 

N 

800 

750 

700 

650 

.` 

f 

J 

l 

1 

f 

600 

550 

500 

R 

450 

R 

7 

400 

U 

350 

300 

250 

200 

Breton 

42040 

GDILl 

--0-- BURLl 

f 

I 

1 

I 

1 

f 

I 

1 

1 

t ~ l ~ 1 

1 

1 1 

1 

f t 

f t 

1 

t 

t 

t 

5/97 6/97 7/97 8/97 9/97 10/97 11/97 12/97 1/98 2/98 3/98 4/98 5/98 

Month 

Figure 98. Variations of monthly mean mixed heights computed from Eq. (16) over the southeastern Louisiana 

coast and eastward over the BNWA. 
w 

1004 

90U 

80U 

700 

600 

oc 

x 

400 

300 

200 

100 

1 I 

Stable Mixed Height Calculation 

Cd Based On WAMDI Formulation ~ 3 ~ 

T,tr =19.0 °C I 

Location: Buoy 42007, Chandeleur Sound 

January 1998 

T tr=Tw, =5.0°C I 

U10 - 6.1 m/s I / ~ I 

SMH Approz.104 m 

I 

I ~ I ~~ I 

4P 

I ~ ~ I 

I 

10 11 12 13 14 15 16 17 18 19 20 

Ulp, m/s 

Figure 99 . Stable mixed layer height nomogram for air temperature of 19°C. Lines indicate temperature 

difference (Ta;r - Tsea)' 
IV. Summary 

Analysis of meteorological and air quality data records obtained during the period of May 

1997 through July 1998 at Breton and Dauphin Islands yields many significant findings . 

" Hourly concentrations of SOZ and NOZ at both stations were less than 6 ppb for over half of 

the study period . 

" Average and maximum concentrations obtained were well below the National Ambient Air 

Quality Standard for both monitored pollutants . 

" Concentrations are higher on average in the fall and winter months at both locations. 

" No significant variations in the median SOz diurnal trends are evident at either location. 

Higher NOZ is more likely in the early morning and, to a lesser extent, in the evening. This 

is an expected characteristic of NO, produced by chemical reactions fueled by solar 

radiation. 

" Maximums of both pollutants are mostly associated with north-northeasterly winds at 

Dauphin Island . 

t Breton SOZ maximums are primarily seen with northerly winds, while NOz maximums are 

generally from the south-southwest. 

" Continental High and Frontal Overrunning synoptic weather patterns are more likely to 

produce higher SOZ over the BNWA, while Gulf Return, Frontal Overrunning, and 

Continental High conditions are mostly associated with higher NO2. 

" SOz concentrations are higher at Dauphin Island than at Breton ; average NOz is nearly 

equivalent but higher maximums are observed at Breton. 

" Short duration (about one day) high NO,, episodes are evident in the Breton data record, 

usually occurring several times each month. 

" Accurate estimation of the drag coefficient, Cd, is essential for many air-sea applications . 

The wind-wave formulation (Eq. (5)) proposed by Hsu (1995a) is recommended for use. 

" Turbulence intensities measured at Breton are in reasonable agreement with those found in 

the literature . However, even the very low elevation terrain of the islands can increase the 

turbulence . 

" In the marine environment, the mixed height is equivalent to the lifting condensation level 

(LCL) under unstable conditions in the presence of cumulus clouds . Methods for estimating 

the LCL from surface parameters and from remotely-sensed input (satellite) are provided for 

use in the absence of in situ data . 

184 
" A nomogram for determining the stability category from routinely observed surface 

parameters is provided. 

" Free-convective (defined here as Z/L < -1 .0) stability was observed at Breton Island from 

4 to 15% of the study period . Monthly mean stability was unstable throughout the year. 

" Under stable conditions, mixed heights as low as approximately 100 m were observed over 

the BNWA. Methods for determining the mixed height under both stable and unstable 

conditions are provided. 

The relatively short-term and non-continuous nature of these datasets makes comparison of 

the annual air quality statistics difficult. However, no significant change in pollutant characteristics 

between this study period and previously published results is evident at either location (with the 

slight increase of NOZ at Breton attributed to station re-location) . On the other hand, since the PSD 

Class I increments for SOZ and NOz are only about 1 ppb (Boubel et al ., 1994), continuous 

monitoring is strongly recommended to protect and preserve the environmental quality of these 

invaluable areas. 

185 
V. References 

Boubel, R. W., D. L. Fox, D. B. Turner, and A. C. Stern. 1994. Fundamentals Of Air Pollution . San 

Diego: Academic Press. 574 pp. 

Code of Federal Regulations. 1994 . Title 40, Protection of Environment, Part 58, Appendix B, 

Quality assurance requirements for prevention of significant deterioration (PSD) air 

monitoring. 

Chang, J. C., M. E. Fernau, J. S . Sire, and D. G. Strimaitis . 1998. A critical review of four types of 

air quality models pertinent to MMS regulatory and environmental assessment missions . 

OCS Study MMS 98-0050. Available from Minerals Management Service, Gulf of Mexico 

Region, New Orleans, LA. 

Donelan, M. A., Dobson, F. W., Smith, S. D., and R. J . Anderson. 1993 . On the dependence of sea 

surface roughness on wave development. J. Phys . Oceanogr., 23 :2143 - 2149 . 

Donelan, M. A., W. M. Drennan, and K. B. Katsaros . 1997. The air-sea momentum flux in 

conditions of wind sea and swell . J. Phys . Oceanogr., 27 :2087 - 2099 . 

Garratt, J. R. 1992. The Atmospheric Boundary Layer. Cambridge University Press. 316 pp. 

Geernaert, G. L., S . E. Larsen, and F . Hansen. 1987 . Measurements of wind stress, heat flux, and 

turbulence intensity during storm conditions over the North Sea. J. Geophys. Res ., 92(C 12) : 

13127 - 13139 . 

Hanna, S . R. 1984. Applications in air pollution modeling. Atmospheric Turbulence and Air 

Pollution Modeling. F. T. M. Nieuwstadt and H. van Dop, Eds ., D. Reidel Publishing Co., 

pp. 275 - 310 . 

Hanna, S. R., L. L. Schulman, R. J. Paine, J . E. Pleim, and M. Baer. 1985 . Development and 

evaluation of the offshore and coastal dispersion model . J. Air Poll . Contr. Assoc., 35 :1039 -

1047. 

Hsu, S. A. 1988. Coastal Meteorology. Academic Press, 260 pp. 

Hsu, S. A. 1992 . An overwater stability criterion for the offshore and coastal dispersion model. 

Boundary-Layer Meteorol., 60 :397 - 402. 

Hsu, S . A. 1995a. A proper wind-stress drag coefficient formulation for computer modeling of seas 

and coastal regions. In Computer Modeling of Seas and Coastal Regions II, C. A. Brebbia, 

L. Traversoni, and L. C. Wrobel (Editors), Computational Mechanics Publications, Boston, 

pp . 413 - 420. 

186 
Hsu, S . A. 1995b. Measurements of SOZ concentration and atmospheric structure in Delta and 

Breton Wildlife Refuges. OCS Study MMS 95-0019 . U.S. Dept. of the Interior, Minerals 

Management Service, Gulf of Mexico OCS Region, New Orleans, LA . 74 pp. 

Hsu, S. A. 1996. Analysis of ambient pollutant concentrations and meteorological conditions 

affecting EPA class I and II areas in southeastern Louisiana, Vol. 1 : Technical Report. OCS 

Study MMS 96-0062 . U.S. Dept. of the Interior, Minerals Management Service, Gulf of 

Mexico OCS Region, New Orleans, LA. 156 pp. 

Hsu, S . A. 1997 . Estimating overwater convective boundary layer height from routine 

meteorological measurements for diffusion applications at sea. J. Appl . Meteor., 36 :1245 -

1248 . 

Hsu, S. A. 1998 . A relationship between the Bowen ratio and sea-air temperature difference under 

unstable conditions at sea. J. Phys . Oceanogr., 28 :2222 - 2226. 

Hsu, S . A., and B. W. Blanchard. 1998. Long-term measurements of SOZ and NOz concentrations 

and related meteorological conditions in the northeastern Gulf of Mexico region . OCS Study 

MMS 98-0020. U.S . Dept. of the Interior, Minerals Management Service, Gulf of Mexico 

OCS Region, New Orleans, LA . 308 pp . 

Large, W. G., and S . Pond. 1981 . Open ocean momentum flux measurements in moderate to strong 

winds. J . Phys. Oceanogr., 11 :324 - 336 . 

Louisiana Office of State Climatology . 1995 - 1998. Louisiana Monthly Climate Review. Available 

from the Dept. of Geography and Anthropology, Louisiana State University, Baton Rouge, 

LA, 70803. 

Kaimal, J. C . and J. J. Finnigan. 1994. Atmospheric Boundary Layer Flows. Oxford University 

Press, New York . 289 pp . 

Kidder, S . Q., and T. H. Vonder Haar. 1995 . Satellite Meteorology. Academic Press, San Diego, 

CA. 466 pp. 

McIlveen, J. F. R. 1986. Basic Meteorology. Van Nostrand Reinhold (U.K.) Co., Ltd. 457 pp. 

Muller, R. A. 1977 . A synoptic climatology for environmental baseline analysis : New Orleans. 

J. Appl . Meteor., 16 :20 - 33 . 

Panofsky, H. A. and J. A. Dutton. 1984. Atmospheric Turbulence . John Wiley . 397 pp . 

Smith, S. D. 1980 . Wind stress and heat flux over the ocean in gale force winds. J. Phys. Oceanogr., 

10:709 - 726 . 

187 
The WAMDI Group. 1988 . The WAM model - a third generation ocean wave prediction model. 

J. Phys . Oceanogr., 18 :1775 - 1810. 

Wu, J. 1982. Wind-stress coefficients over sea surface from breeze to hurricane. J. Geophys. Res., 

87(C 12) :9704 - 9706. 

Zannetti, P. 1990 . Air Pollution Modeling. Van Nostrand Reinhold. 444 pp . 

188 
QPQS~,"NT OFTy~'y The Department of the Interior Mission 

o`' k p As the Nation's principal conservation agency, the Department of the Interior has responsibility for 

most of our nationally owned public lands and natural resources. This includes fostering sound use of 

our land and water resources; protecting our fish, wildlife, and biological diversity; preserving the 

_ A9 environmental and cultural values of our national parks and historical places ; and providing for the 

4RCH 3 ~~ enjoyment of life through outdoor recreation . The Department assesses our energy and mineral 

resources and works to ensure that their development is in the best interests of all our people by 

encouraging stewardship and citizen participation in their care. The Department also has a major 

responsibility for American Indian reservation communities and for people who live in island territories 

under U.S . administration . 

The Minerals Management Service Mission 

As a bureau of the De p artment of the Interior , the Minerals Mana g ement Service's (MMS) p rima ry 

responsibilities are to manage the mineral resources located on the Nation's Outer Continental Shelf 

(OCS), collect revenue from the Federal OCS and onshore Federal and Indian lands, and distribute 

~< 

those revenues. 

S ~'~NAGEUv Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program 

administers the OCS competitive leasing program and oversees the safe and environmentally sound 

exploration and production of our Nation's offshore natural gas, oil and other mineral resources. The 

MMS Royalty Management Program meets its responsibilities by ensuring the efficient, timely and 

accurate collection and disbursement of revenue from mineral leasing and production due to Indian 

tribes and allottees, States and the U.S . Treasury . 

The MMS strives to fulfill its responsibilities through the general guiding principles of : (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially affected 

parties and (2) carrying out its programs with an emphasis on working to enhance the quality of life for 

all Americans by lending MMS assistance and expertise to economic development and environmental 

protection .