Land Use and

T 1 /^N TT C* * Land Cover Intarmation 

and Air-Quality Planning **w / &

GEOLOGICAL SURVEY ?-$ 01 E S S I O H A L PAPER

Land Use and

Land Cover Information

and Air-Quality Planning

By WALLACE E. REED and JOHN E. LEWIS

THE INFLUENCES OF LAND USE AND LAND 

COVER IN CLIMATE ANALYSIS

GEOLOGICAL SURVEY PROFESSIONAL PAPER 1099-B

An example of environmental analysis using 

land use and land cover information

UNITED STATES GOVERN M EN T PRINTING OFFICE : 1978
UNITED STATES DEPARTMENT OF THE INTERIOR 

CECIL D. ANDRUS, Secretary

GEOLOGICAL SURVEY

H. William Menard, Director

Library of Congress Cataloging in Public Data

Reed, Wallace E.

Land use and land cover information and air-quality planning.

(Professional paper—Geological Survey ; 1099-B) Bibliography: p.

1. Air-quality management—Virginia. 2. Land use—Environmental aspects—Virginia. 3. Virginia—Climate. 

I. Lewis, John E., 1937- joint author. II. Title. III. Series: United States. Geological Survey. Professional paper ; 1099-B.

TD883.5.V8R43 363.6 78-13506

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. 20402 

Stock Number 024-001-03121-3
CONTENTS

Page

Abstract ___________________________________________ Bl

Introduction _________________________________________ 1

Acknowledgments _____________________________________ 2

Land use and land cover and air-quality planning __________________ 2

Air-quality control strategies ___________________________ 2

Strategy evaluation by Federal and State agencies ________-__——— 2

Land use and land cover information needed for comprehensive air-quality

planning _________________________________ 3

Land use and land cover information developed in the CARETS project ______ 3

Land use and land cover classification scheme formulated by the U.S.

Geological Survey ____________________________——— 5

Measurement detail and accuracy ____________________—— 6

Polygon recording system _______________________—— 6

User products __________________________________ 6 

Land use and land cover information for air-quality planning in the NorfolkPortsmouth standard metropolitan statistical area ______—————— 6 

Land use and land cover information used for the initial Norfolk area control strategy and implementation plan _____————————————— 9 

Available land use and land cover information ________—_——— 9

Estimating the initial emission inventory _______—————————— 9

Evaluating and refining strategies for the Norfolk area _—————————— 9

Selection of initial control strategy __________————————— 9

Evaluating the initial control strategy __________-_--_—————— 11

Land use and land cover and emission estimates ______———————— 13

Area sources _______________________-_—————————— 13

Point sources ______________________________—————— 13

Seasonality _________________________-___—————— 14

Future emission patterns ______________—_—————————— 14

Land use and land cover and Norfolk area emissions patterns _——————— 14

Determining spatial distribution patterns of air quality _—————————— 24

Estimating pollutant diffusion patterns ______———————— 24

Model used to estimate Norfolk area air quality ———————————— 26 

Norfolk area airflow characteristics _______—————————————— 28 

Selection of grid patterns for estimating pollutant concentrations ——— 31 

Norfolk land use and land cover and estimated air-pollutant concentration patterns __________-_____—————————————— 31

Sulfur dioxide concentrations ______—_—————————————— 34

Suspended particulate concentrations ___———————————— 41

Conclusions _________________—_———————————————————— 41

References ________________-__-_—_————————————————— 42

ILLUSTRATIONS

Page

FIGURE 1. Map of CARETS showing 1970 Norfolk-Portsmouth Standard Metropolitan Statistical Area

(SMSA) ____________________________-__—————————————————————— B4

2. Controlled photomosaic showing part of the Norfolk-Portsmouth SMSA ———————————————— 7

3. Maps showing Level I and Level II land use and land cover of part of the 1970 Norfolk-Portsmouth

SMSA _____________________________————————————————————————— 8

in
IV CONTENTS

Page

FIGURES 4-14. 1970 Norfolk-Portsmouth SMSA:

4. Area source emission estimating grid cell system _________————————————————— BIO

5. 1970 land use and land cover selected for air-quality planning ___————_———————— 12

6. Selected point sources and centroids of area emission cells ______————————————— 15

7. Proposed land use and land cover, 1985 ________—__——————————————————— 16

8. Estimated emissions of sulfur dioxide, 1972_ _______________————————————— 18

9. Estimated emissions of sulfur dioxide, winter 1971-72 ________________—————— 19

10. Estimated emissions of sulfur dioxide, 1985_————————————————————————————— 20

11. Estimated emissions of particulates, 1972 _____——————————————————————————— 21

12. Estimated emissions of particulates, winter 1971-1972 ________————————————————— 22

13. Estimated emissions of particulates, 1985 _____—_—__——————————————————— 23

14. Location of air-quality sampling stations, October 1972 ______—_————————————— 25

15. Treatment of point (A) and virtual point for area source (B and S) diffusion patterns in air-quality display model (AQDM) _________________________________________ 27

16. Annual stability wind rose, December 1966-November 1971, Norfolk Naval Air Station ——————— 29

17. Winter stability wind rose, December 1966-November 1971, Norfolk Naval Air Station ________—— 30

18-24. 1970 Norfolk-Portsmouth SMSA:

18. Pollution concentration estimating points__—————__—___——————————————— 32

19. Estimated average concentrations of sulfur dioxide, 1972 ____________________ 35

20. Estimated average concentrations of sulfur dioxide, winter 1972 _____—____—————— 36

21. Estimated average concentrations of sulfur dioxide, 1985 __________________— 37

22. Estimated average concentrations of particulates, 1972 _____________________ 38

23. Estimated average concentrations of particulates, winter 1972 _———————_——————— 39

24. Estimated average concentrations of particulates, 1985 _________——————__——————— 40

TABLES

Page

TABLE 1. Land use and land cover classification scheme for use with remotely sensed data _______—_—— B5

2. Example of land use and land cover statistics ______________—_——————————————— 11

3. Sample pages of table of estimated Norfolk-Portsmouth SMSA, 1972 annual, winter 1971-72 and

estimated annual 1985 emission inventories _______________———————_—————— 13

4. Point sources included in air diffusion of modeling of Norfolk-Portsmouth SMSA —_———————— 24

5. Estimates of concentration of pollutants over receptors _______________——_—————— 33

6. Example of estimates of point and area source contributions and recommended reduction programs

for selected receptor points _____________________________—______———— 33

7. Estimates of percent of total contribution of specific sources to selected receptor estimating points,

Norfolk-Portsmouth SMSA, 1972 annual ___________________————-———————— 34
THE INFLUENCES OF LAND USE AND LAND COVER 

IN CLIMATE ANALYSIS

LAND USE AND LAND COVER INFORMATION 

AND AIR-QUALITY PLANNING

By WALLACE E. REED x and JOHN E. LEWIS

ABSTRACT

The land use and land cover information developed by 

the U.S. Geological Survey in the Central Atlantic Regional 

Ecological Test Site project has been proven useful when 

used in an improved technique for estimating emissions, 

diffusion, and impact patterns of sulfur dioxide (S02 ) and 

particulate matter.

Implementation of plans to control air quality requires 

land use and land cover information, which, until this time, 

has been inadequate. The land use and land cover data were 

used in updating information on the sources of point and 

area emissions of S02 and particulate matter affecting the 

Norfolk-Portsmouth area of Virginia for the 1971-72 winter 

(Dec.-Jan.-Feb.) and the annual 1972 period, and for a 

future annual period—1985. This emission information is 

used as input to the Air Quality Display Model of the Environmental Protection Agency to obtain diffusion and impact patterns for the three periods previously mentioned. 

The results are: (1) During the 1971-72 winter, estimated 

S02 amounts over an area with southwest-northeast axis in 

the central section of Norfolk exceeded both primary and 

secondary levels, (2) future annual levels of S02, estimated 

by anticipated residential development and point-source 

changes, are not expected to cause serious deterioration of 

the region's present air quality, and (3) for the 1971-72 

winter, and annual 1972, period the diffusion results showed 

that both primary and secondary standards for particulate 

matter are regularly exceeded in central Norfolk and Portsmouth. In addition, on the basis of current control programs, 

the 1985 levels of particulate matter are expected to exceed 

the presently established secondary air-quality standards 

through central Norfolk and Portsmouth and in certain areas 

of Virginia Beach.

Land use and land cover information can be used to estimate emissions for inputs to diffusion models and to interpret 

the implications of diffusion patterns for: (1) Implementing 

various control strategies, (2) selecting sites of air sampling stations, and (3) predicting the effects that proposed 

changes in land use and land cover might have on emission 

patterns and air quality.

1 Department of Environmental Sciences, University of Virginia, 

Charlottesville, Va.

2 Department of Geography, McGill University, Montreal, Canada.

INTRODUCTION

As an initial step toward satisfying the nationwide need for current, comparable land use and land 

cover information, the U.S. Geological Survey 

(USGS) compiled land use and land cover information in its Central Atlantic Regional Ecological Test 

Site (CARETS) project.3 Among the many uses of 

that information are its applications in evaluating 

air-quality control strategies and implementation 

programs.

A majority of the States' air-quality control implementation plans proposed during 1972 are highly 

dependent upon emission-control strategies. Basic 

guidelines for preparing State air-quality implementation programs were established in the Clean Air 

Act of 1970 (PL 90-604) as well as in the Federal 

Registers, April 7 and August 14, 1971 (U.S. Environmental Protection Agency, 1971b and 1971c). 

Effective consideration of alternative quality-control strategies and implementation plans was seldom 

feasible due to lack of time and inadequate land use 

and land cover information. Necessary land use and 

land cover information for those purposes was compiled during the CARETS study.

This paper examines the relationship between air 

quality and land use and land cover, and identifies 

the types of land use and land cover information 

needed to evaluate air quality control strategies. It 

also presenst a description of the land use and land 

cover information available, and suggests applications of this information to Norfolk area air-quality 

planning.

3 The CARETS Project was sponsored in part by the National Aeronautics and Space Administration under Interagency Memorandum of 

Understanding No. S-70243-AG. (See Reed and Lewis, 1975 NTIS No. 

E-77-10018.)

Bl
B2 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

The data were collected during a study of the air 

quality in the Norfolk-Portsmouth, Virginia, Standard Metropolitan Statistical Area (SMSA) and 

focuses on strategies to control the effects of sulfur 

dioxide and suspended particulates. The Norfolk 

area was selected for two primary reasons. First, 

the physical characteristics of its location and its 

air-quality planning problem are similar to those of 

many other metropolitan regions. Second, the greatest range of land use and land cover data and specific 

information produced in the CARETS project had 

been for the Norfolk area (Alexander, 1972).

ACKNOWLEDGMENTS

The extensive advice and assistance received from 

the staff of the Commonwealth of Virginia, State 

Air Pollution Control Board and personnel of the 

board's Air Quality Control Region VI in Virginia 

Beach; the Southeastern Virginia Planning District 

Commission; Virginia Department of Highways; the 

Environmental Protection Agency, Region III, 

Philadelphia, Pa.; and the Office of Air Programs, 

Office of Land Use Planning in North Carolina are 

gratefully acknowledged, as are the research efforts 

of Gregory A. Shoemaker and Nelson M. Nones.

LAND USE AND LAND COVER AND 

AIR-QUALITY PLANNING

Developing and evaluating air-quality control 

strategies depend on identifying current and anticipated relationships between patterns of land use and 

land cover and: (1) amounts of air pollutants over 

specific land use and land cover categories; (2) 

amounts of air pollutants over adjacent or doWnwind areas; and (3) the impacts of various concentrations of air pollutants on land uses and land 

cover.

Land use and land cover activities affect air 

quality by emitting manmade and natural pollutants. These pollutants are dispersed by local, regional, and global airflow and affect the health, 

safety, operating costs, and other characteristics of 

all land use and land cover activities. The intensity 

of effect depends on the types of chemical and physical impacts that pollutants may produce, on the degree to which pollutants are concentrated in the air, 

and on the length of time a given activity or process 

is exposed to pollutants. The concentration of pollutants depends on the quantity emitted and on the 

location of emitting sources relative to the direction 

and stability of airflows. Land surface characteristics such as roughness, albedo, thermal diffusivity,

amount of water, and amount of transpiring surfaces in a given area influence the meteorological 

conditions affecting the stability of airflows. Each 

of these surface characteristics can be extensively 

modified by the activities or processes conducted on 

and structures that occupy urban and rural land.

AIR-QUALITY CONTROL STRATEGIES

Given the relationships between land use and land 

cover and airflows, one can employ a number of 

strategies to achieve given levels of air quality. The 

various perspectives from which strategies may be 

developed include:

I. Focus on emission sources—emission-source 

control

1. Change in type of activity.

2. Change in fuel and other process inputs.

3. Installation of emission-control devices.

4. Change in timing of emission.

5. Change in the spatial distribution of stationary sources with respect to airflow and receptor locations.

II. Focus on airflow—airflow modification

1. Changes in surface roughness.

2. Changes in surface albedo.

3. Changes in transpiring surface area.

4. Changes in local precipitation.

III. Focus on receptor

1. Change in the activities affected by pollutants.

2. Change in contact between air and receptor 

through structural and air-conditioning 

modifications.

3. Change in the timing of stationary and mobile 

receptor activities to avoid periods of high 

concentration.

4. Change in the spatial distribution of stationary and mobile receptors.

Each of these strategies involves varying degrees 

of land use and land cover management and the need 

for land use and land cover information.

For further discussions of control strategies focused on urban areas see Allan M. Voorhees and 

Associates and Ryckman, Edgerley, Tomlinson and 

Associates (1971); and Kennedy and others (1971).

STRATEGY EVALUATION BY FEDERAL AND 

STATE AGENCIES

The Clean Air Act of 1970 and Environmental 

Protection Agency (EPA) action required State and 

local air-quality planning agencies to identify airquality control regions, to select pollutant control
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B3

strategies, and to develop implementation plans by 

early 1972 (PL 90-604 and U.S. Environmental Protection Agency, 1971b and 1971c). Because of time 

and cost constraints, most planning agencies could 

not assemble the types of land use and land cover 

information needed to evaluate fully the range of 

strategies that might have been applied in each region. Therefore, EPA most frequently encouraged 

the collection of land use and land cover information 

suitable for identifying regions with similar airquality control problems and suitable for analyzing 

strategies focused on emission source controls.

The strategy of controlling emissions at their 

source required land use and land cover information 

to identify sources and was in line with the goal of 

reducing total nationwide emissions regardless of 

the spatial distribution of sources. Furthermore, 

given the types of sources and the political realities 

facing planners in most air-quality control regions, 

emission-source control strategies appeared to be 

the easiest to implement. Because the Federal Government is attempting to control mobile emission 

sources, local and State action could be directed toward controlling point and area emission sources, 

the cost of which appeared to be less than the cost 

of reorganizing land use and land cover patterns or 

changing the timing of activities or processes emitting or receiving pollution.

In the absence of more detailed land use and land 

cover information, emission-source control strategies appeared to be most effective in achieving primary and secondary air-quality standards without 

inhibiting growth in each control region. Based on 

this strategy, regional implementation plans were 

developed that called for rollback procedures or proportional reductions in regional emissions (U.S. Environmental Protection Agency, 1970 and 1971c).

Although the emission-source strategy is reasonable, strategies focusing on land use management, 

as yet unevaluated, might be more effective, either 

individually or in combination with adopted emission-source strategies, in specific air-quality control 

regions. EPA's current program of planning for Air 

Quality Maintenance Areas calls for the refinement 

of existing strategies and plans and the evaluation 

of alternative strategies.

Information adequate for this planning and testing of alternatives is becoming available. Specifically, the U.S. Geological Survey is supplying current, comparable land use and land cover information that can easily be related to the emission, receptor, and airflow characteristics of local, regional, 

or nationwide areas. Detailed meteorological data

for air-quality control regions are available from 

the National Oceanic and Atmospheric Administration. Air-quality sampling networks are operating 

or being established in each control region. Where 

these sampling programs are not yet adequate and 

where adequate meteorological and land use and land 

cover data exist, models for estimating pollutant diffusion and concentration can be used to evaluate 

planning strategies related to land use and land 

cover.

LAND USE AND LAND COVER INFORMATION NEEDED 

FOR COMPREHENSIVE AIR-QUALITY PLANNING

Comprehensive air-quality plans should evaluate 

the short- and long-term physical and social impacts 

of a range of strategies along with their potential 

for implementation. The types of land use and land 

cover information needed for comprehensive plans 

include:

1. Activity location.—For each type of process or 

fuel consumed, the current and anticipated location of stationary and mobile activities emitting and receiving pollutants.

2. Activity behavior.—For each type of pollutant, 

the timing and intensity of emissions or reception.

3. Activity physical characteristics.—The geometry, albedo, and surface material of the area 

and the region's activities and processes affecting local airflows.

These types of land use and land cover information 

are essential for developing detailed emission inventories, for analyzing airflow patterns, for evaluating 

probable impact on receptor activities, for identifying locations for air-quality sampling stations, and 

for improving the calibration of models used to estimate pollutant diffusion. Much of this land use and 

land cover information is being provided directly or 

can easily be estimated from the USGS land use and 

land cover information.

LAND USE AND LAND COVER INFORMATION 

DEVELOPED IN THE CARETS PROJECT

The CARETS project was one of a series of experimental studies by the USGS to establish a coordinated Federal program for the standardization 

and production of land use and land cover data. 

These activities consisted of interpreting land use 

and land cover data from remotely sensed imagery 

provided by NASA's Aircraft and Earth Resources 

Satellite Programs, organizing these data into specific types of information, and providing this infor-
B4 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

CENTRAL ATLANTIC REGIONAL 

ECOLOGICAL TEST SITE

FIGURE 1.—Map of CARETS showing 1970 Norfolk-Portsmouth Standard Metropolitan Statistical Area

(SMSA).
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B5

mation in statistical and graphical formats to cooperating State, regional, and private users with 

responsibilities for land use and land cover planning 

and management. The CARETS project includes the 

Norfolk-Portsmouth SMSA (Standard Metropolitan 

Statistical Area) area of Virginia (fig. 1).

LAND USE AND LAND COVER CLASSIFICATION SCHEME 

FORMULATED BY THE U.S. GEOLOGICAL SURVEY

To be of maximum effectiveness to users, land use 

and land cover data must be organized in categories 

related directly to a range of land management decisions or in categories from which estimates of such 

data can easily be made. The first version of the 

USGS land use and land cover classification scheme 

(Anderson and others, 1972) is represented by 

Levels I and II in table 1. In table 1, Levels III and 

IV provide examples of how the basic system can

be expanded to meet the needs of various users, in 

this case, those of air-quality planners.

In the CARETS project the land use and land 

cover classification system was organized to derive 

Level I information primarily from satellite data. 

This level is intended for use in the most general 

forms of land use and land cover analysis and decisionmaking. Level II is intended to be derived primarily from high-altitude aerial photographs and 

can be used for decisions requiring increasingly detailed information. Successively more detailed levels 

of classification of land use and land cover (Levels 

III and IV of table 1) can be provided by State and 

local user agencies for local air quality evaluation 

and planning. Such planning usually requires more 

information on urban and agricultural activities 

than can be provided directly by Level II data. Many 

other Level I and II categories such as information

TABLE 1.—Land use and land cover classification scheme for use with remotely sensed data

Level I

1 Urban and built-up _.

Level II

11 Residential __

12 Commercial and 

services.

13 Industrial _____

2 Agricultural land

3 Rangeland

4 Forest land

5 Water

6 Nonforested wetlands

7 Barren land ______.

8 Tundra ________.

9 Permanent snow and 

icefields.

14 Extractive

15 Transportation communications and 

utilities.

16 Institutional __________

17 Strip and clustered 

settlement.

18 Mixed ________________

19 Open and other _______

21 Cropland and pasture _

22 Orchards, groves, bush 

fruits, vineyards, and 

horticultural areas.

23 Feeding operations ___

24 Other ________________

31 Grass ________________

32 Savannas (palmetto 

prairies).

33 Chaparral _________

34 Desert shrub __________

41 Deciduous __________

42 Evergreen (coniferous 

and other).

43 Mixed ________________

51 Streams and waterways52 Lakes ___________

53 Reservoirs ________

54 Bays and estuaries ____

55 Other ________________

61 Vegetated ____________

62 Bare _________________

71 Salt flats _____________

72 Beaches ______________

73 Sand other than 

beaches.

74 Bare exposed rock _____

75 Other _____________

81 Tundra _______________

91 Permanent snow and 

icefields.

111

112

113

114

Level III

High-density

residential. 

Medium-density

residential. 

Low-density

residential. 

Residential

construction.

Level IV

1111 High-density residential structures.

1112 Yards and open space.

1113 Parking.

1114 Streets and highways.

1115 Height of structures.

1116 Height of vegetation.

Source: Anderson and others, 1972.
B6 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

on water and bare land activities can be used effectively as provided by the systems. The example 

Level III and IV categories are suggested classifications related to specific activities or processes (industry by Standard Industrial Code, agriculture by 

crop type, construction affecting each type of Level 

III activity) from which emissions or receptor impact can be estimated. These categories can also be 

used to identify three-dimensional profiles of structures and materials for various land uses and land 

cover that may affect airflow. Each of these categories could be measured uniformly nationwide or 

modified for the specific urban and rural characteristics of various EPA administrative or control 

regions.

MEASUREMENT DETAIL AND ACCURACY

The data used in this report are from high-altitude aerial photographs and were mapped onto a 

controlled photomosaic base at a scale of 1:100,000. 

Land uses covering an area of not less than 4 ha 

(hectare) can be interpreted effectively at this 

scale at Level I and II. This degree of detail insures 

the rapid assembly of data useful to a wide range 

of Federal and State users.

Figure 2 shows a part of a controlled photomosaic 

covering the Norfolk, Va., area, and figure 3 shows 

the same area as mapped at Level I and Level II.

Experiments are proceeding to determine the levels of accuracy needed by various users. With EPA 

and State-sponsored registration systems in use to 

identify the principal emission sources, air-quality 

evaluators might be able to accept levels of error in 

land use and land cover areal measurement of 5 

percent or greater, in favor of rapid complete regional coverage and frequent updating of area measurements indicating land use and land cover change.

POLYGON RECORDING SYSTEM

Land use and land cover data are prepared for 

computer manipulation by converting the boundaries of the individual land use units (known as polygons) into digital form. In this form a wide variety 

of computations can be made upon the data. For 

example, computations for percentage of total area 

for particular land use categories can be calculated 

easily for specific census tracts, jurisdictions, or 

other enumeration areas such as grid patterns established for air pollutant emission estimating.

USER PRODUCTS

After the data have been digitized and stored in 

computer-readable form, various types of information can be derived. Tables of area, perimeter, rate 

of change and other characteristics of land use and 

land cover type can be prepared for any jurisdiction requested. In addition to tabular output, graphic 

information can be provided or, if needed, the original remotely sensed data.

By the end of 1973, land use and land cover information having a minimum mapping unit size of 

4 ha was available for the entire CARETS area.

EPA anticipates the early completion of a nationwide information system to monitor the location and 

change in major point and area emission sources. 

This National Emission Data System (NEDS) will 

identify, by Universal Transverse Mercator (UTM) 

coordinates, all point sources emitting more than 

100 megagrams (Mg) annually of any of the five 

major pollutants along with any other high-emission sources (U.S. Environmental Protection 

Agency, 1971b and 1971c). Area and mobile source 

emission contributions will be monitored by county 

on the basis of fuel purchases.

The currently operational USGS nationwide land 

use and land cover mapping and data compilation 

program provides a useful source of land information for air-quality control analysis. The evaluation 

of air-quality control strategies for the NorfolkPortsmouth SMSA presented in this report provides 

an example of the type of use which can be made of 

the information products prepared by this program.

LAND USE AND LAND COVER INFORMATION

FOR AIR-QUALITY PLANNING IN THE

NORFOLK-PORTSMOUTH STANDARD

METROPOLITAN STATISTICAL AREA

The land use and land cover, geographic setting, 

and air-pollution characteristics of the NorfolkPortsmouth SMSA, which includes the cities of 

Norfolk, Portsmouth, Chesapeake, and Virginia 

Beach, present a site and air-quality planning problem similar to many East Coast and Midwestern 

metropolitan areas. Air-quality planning for this 

major segment of Virginia's Air Quality Control 

Region VI indicates how land use and land cover information can be used at regional, State and national scales. Virginia Air Quality Control Region 

VI includes both the 1970 Norfolk-Portsmouth 

SMSA, and the industrial area of Newport News 

and Hampton, separated from Norfolk by Hampton 

Roads, the broad estuary at the mouth of the James 

River (Commonwealth of Virginia, 1972a).

The Norfolk area is located on the coastal plain 

of Virginia at the mouth of the Chesapeake Bay 

and contains the only stretch of ocean frontage
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B7

2 mi 

I

4km

FIGURE 2.—Controlled photomosaic showing part of the Norfolk-Portsmouth

SMSA.

which is easily accessible to much of central Virginia and northern North Carolina (fig. 1). The 

area's economy and land use reflect strong and rapidly growing industrial, commercial, transportational, institutional, recreational, and residential 

components.

Geographic characteristics that influence the 

area's airflows and pollutant dispersion are a nearly 

flat topographic surface, extensive water surface 

in wetlands, rivers, and estuaries, proximity to the 

open Atlantic Ocean, and an extensive mixture of 

agriculture and forest lands.

Primary activities in the Norfolk area include the 

base of naval operations for the Atlantic Fleet, shipbuilding and repair, coal and grain exporting, general shipping, chemical and fertilizer manufacturing, wholesaling to surrounding eastern Virginia 

and North Carolina, truck farming and fishing, and 

tourism focused on the area's ocean beaches, estuarine waterfront, and wetlands. The processing, 

power generation, heating, and transportation associated with each of these activities are the primary contributors to Norfolk area air pollution. The 

area's strong economy and attractive setting for
B8 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

E

CN-H
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING

retirement have resulted in extensive residential development and a concomitant increase in area source 

contributions to pollution from space heating and 

automobiles. Sulfur dioxide and suspended particulates are the primary Norfolk area pollutants because of the types of fuel oil used for heating and 

power generation in the area, the large amounts of 

sulfur used in producing fertilizer and other area 

manufacturing processes, the patterns of traffic 

flow, the large construction projects underway 

throughout the area, the age of many of the area 

manufacturing facilities, and the processing technologies of those facilities. These two pollutants are 

the focus of this study of air quality planning.

LAND USE AND LAND COVER INFORMATION USED FOR

THE INITIAL NORFOLK AREA CONTROL STRATEGY

AND IMPLEMENTATION PLAN

While developing its sulfur dioxide and suspendedparticulate control strategy and implementation 

plan for the Norfolk-Portsmouth SMSA, the Virginia Air Pollution Control Board had little time or 

money for collecting a wide range of land use and 

land cover and geographic information on the area 

(Commonwealth of Virginia, 1972a). In selecting 

its strategy, the board followed procedures recommended by EPA (Ozolins and others, 1966; Duprey, 

1968; U.S. Environmental Protection Agency, 

1970). These procedures rely on the availability of 

land use and land cover information adequate for 

identifying the location of general areas and specific points having different activities and pollutant 

emission characteristics. Having identified the configuration of area and point sources, they estimated 

annual and seasonal emissions to identify regions 

for air-quality control planning. From estimated 

total levels of regional emissions, the Air Pollution 

Control Board designed a specific emission reduction strategy focused on controlling point and area 

sources to bring the region within primary and secondary air-quality standards without inhibiting the 

region's growth.

AVAILABLE LAND USE AND LAND COVER 

INFORMATION

To develop its Norfolk area control strategy, the 

Virginia Air Pollution Control Board had access to 

the following land use and land cover information: 

The 1965 Southeastern Virginia Planning District 

Commission regional land use and land cover map; 

U.S. Geological Survey 1:24,000-scale topographic 

maps; various highway and city maps; low-altitude 

black and white aerial photographs; and directories 

of commercial, industrial, and other activities

(Southeastern Virginia Planning District Commission, 1969). This land use and land cover information was of differing accuracy, scale, and date, and 

considerable time and cost were required to recompile the information at a uniform scale and in categories suitable for air quality planning.

ESTIMATING THE INITIAL EMISSION INVENTORY

In preparing its initial inventory of sulfur dioxide 

and particulate emissions in the Norfolk area, the 

Air Pollution Control Board used the land use and 

land cover information to determine the location of 

large point emission sources and to construct the 

grid system in figure 4 identifying areas having 

relatively homogeneous types and densities of 

activities.

The cells of the grid pattern constructed by the 

board seldom coincided in size and shape with the 

areas of usage designated on available land use and 

land cover maps. Thus, land use and land cover 

densities for each grid often had to be interpolated. 

To estimate area emissions for residential land use 

and land cover, the percent of each 1970 U.S. census enumeration district contained in each cell was 

estimated, and that percentage of the district's population was assigned to the cell. Traffic counts supplied by State and Federal agencies indicated the 

highway, airline, rail and shipping traffic densities 

for each cell. Using the previously mentioned information and data on total local fuel purchases and 

materials used in different types of manufacturing, 

the board estimated the total area emissions of sulfur dioxide and particulates for the 1971 annual, 

winter, and summer periods. Quantities of point 

source emissions for annual and seasonal periods 

were reported by various firms and institutions, or 

emission amounts were estimated from the timing 

of operations, magnitude, and type of activity at 

the source.

EVALUATING AND REFINING STRATEGIES FOR 

THE NORFOLK AREA

SELECTION OF INITIAL CONTROL STRATEGY

When preparing its plan, the board had little 

time for detailed evaluation of the spatial distribution of housing and other land uses that emit or 

receive air pollutants. Nor could it sample or estimate pollutant diffusion patterns in the area. Rather, 

it compared the initially estimated annual total 

Norfolk area emission inventory to national and 

State primary and secondary standards for levels 

of sulfur dioxide and particulates. The board then 

designed an areawide emissions reduction strategy
BIO THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

7s'6

60 

.S•8

o t05
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING Bll

and an air-quality sampling program. The strategy 

and program focused mainly on controlling local 

point sources and on anticipating the local impact 

of the nationwide auto-emission control (Commonwealth of Virginia, 1972a).

EVALUATING THE INITIAL CONTROL STRATEGY

The Air Pollution Control Board recognized that 

it could make considerable improvement in the initial inventory. Since July 1972, collection of point 

source information has been improved by the institution of a mandatory registration and permit program (Commonwealth of Virginia, 1972b). This 

program requires that all large sources emitting 

pollutants provide detailed information on types of 

pollutants, levels of pollution, hours of operation, 

and physical conditions that affect emission levels 

and diffusion, such as stack height, pollutant exit 

velocities, and temperatures. Data-collection programs related to residential space heating and other 

area source emissions are not as detailed. To evaluate currently adopted and alternative strategies for 

controlling sulfur dioxide and suspended particulates in the Norfolk area, specific types of land use 

and land cover and airflow information are needed 

to supplement these improved emissions data. This 

information includes the location of activities emitting these pollutants; the level and timing of their 

emission; the pattern of their diffusion and concentration over receptor land uses; and the impact of 

such concentration on these land uses and land cover. 

This information should be available for both current and future periods.

Much of the land use and land cover information 

needed to update and improve the area source emission inventory and to evaluate alternative air-quality 

control strategies for the Norfolk area was available 

from the U.S. Geological Survey. The CARETS 

project produced Norfolk area land use and land 

cover information interpreted at Levels I and II at 

a 4-ha minimum mapping unit size. The CARETS 

project supplied to the Air Pollution Control Board 

maps of these data at a scale of 1:100,000 for 1959 

and 1970, and a similarly scaled UTM-gridded photomosaic of the area.

The 1970 Level II land use map was overlaid with 

the area source emission estimating grid cell system 

previously established by the board (fig. 4). For 

each grid cell the area and percentage of different 

Level II land uses and land cover were calculated. 

Experience gained in developing the earlier area 

source emissions inventory indicated that differentiation of Norfolk area residential land use and land

cover (Level II) into a more detailed Level III classification of low-, medium-, and high-density residential areas would provide a more useful base for 

area source estimates. Areas of differing density 

were identified from Southeastern Virginia Planning District Commission records, plans, and standards. Their locations were plotted on the Level II 

map. Level III residential areas were calculated and 

included in the land use and land cover area statistics for each grid cell. The percentage of land use 

and land cover for various cells (table 2) provides 

an example of the type that can be generated from 

such maps.

The initial emission source inventory indicated 

that a map of a selected set of Level I, II, and III 

land uses and land cover would effectively emphasize 

the spatial relationship between emitter and receptor 

land uses and land cover and could highlight the 

problems of selecting particular control strategies. 

Figure 5 displays the Norfolk-Portsmouth SMSA 

pattern of residential, commercial/business, water, 

and other land uses and land cover. This figure was 

prepared from the Level I, II, and III maps and was 

overlaid with local jurisdictional boundaries along

TABLE 2.—Example of land use and land cover statistics

[Percentage of 1970 Level II and III land use in the Norfolk-Portsmouth 

SMSA by selected area emission source grid cells (fig. 4). All category 

codes keyed to classification in table 11

Cell 

No.

49

50

51

52

54

55

56

57

58

59

60

61

62

63

64

65

66

Category Code

Percentage of Area 

Category Code _ _

Percentage of Area

Percentage of Area

Percentage of Area 

Category Code - _

Percentage of Area 

Category Code _

Percentage of Area

Percentage of Area

Percentage of Area

Percentage of Area 

Category Code . _

Percentage of Area 

Category Code _ _

Percentage of Area 

Category Code _

Percentage of Area 

Category Code _

Percentage of Area

Percentage of Area 

Category Code __

Percentage of Area 

Category Code __

Percentage of Area 

Category Code

Percentage of Area

_ . 15

__ 15 

_ . 15

__ 05 

.111

__ 25 

__. 12

__ 05 

_. 42

.._ 03

__. 54

__ 05 

_. 54

__ 10 

. 54

__ 05 

_. 54

__ 60 

__. 12

__ 05 

. 54

__ 60

_ . 54

__ 82 

_. 54

__ 60 

. . 54

__ 66 

_ .112

__ 55 

__. 54

__ 04 

.112

__ 70

12

05 

19

05 

19

10 

16

03 

12

20 

16

30 

16

35 

12

05 

112

40 

111

15 

52

10

74

OS 

41

22 

19

08 

54

15 

15

08 

52

04

54

80 

54

54 

54

65 

111

15 

15

17 

111

05 

15

25 

16

05

54

80 

112

05 

112

05 

112

07 

12

18 

12

16 

12

18 

15

04

112

112

54

77 

54

60 

19

35 

53

05 

19

15

15

20 

12

03 

74

03 

16

02 

19

06 

16

22

12

22

15

25 

112

25

70

19

05 

42

02 

16

05 

15

03 

16

08 

112

36

19

02 

19

02 

13

03

19

12

15

01 

15

01
B12 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

GQ

o

fc
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING BIS

with the board's original area source emission estimating grid cell system (fig. 4).

LAND USE AND LAND COVER AND EMISSION 

ESTIMATES

AREA SOURCES

The pattern of variously sized area source emission estimating grid cells established by the board 

encompasses similar densities and types of land use 

and land cover (fig. 5). The 25-km2 and 100-km2 

cells to the east and south of Norfolk and Portsmouth, however, are less diversified than the smaller 

cells covering the central cities.

The detailed Level II and III land use and land 

cover map was used to verify the concentration of 

housing and other activities on which the board 

based its initial estimate of area emissions. Where 

densities of land use and land cover appeared to be 

underestimated or overestimated, adjustments for 

the area emission values in these cells were made 

and later confirmed by officials of the Virginia Air 

Pollution Control Board, Region VI. In the course 

of this checking, it was found that some values that 

the initial inventory attributed to area emission 

sources should have been assigned to point sources.

From updated land use and land cover analysis 

and changes in traffic patterns, an annual 1972 and 

winter 1971-72 emissions inventory was estimated.

Several stations selected from this inventory are 

presented in table 3.

Figure 6 indicates the centroid of each cell's area 

source emission. In developing air-quality sampling 

programs and estimating pollutant diffusion, working with this centroid of activities is much more 

useful than dealing with the geographic center of 

each cell, especially for the larger cells in the Norfolk area where urban activities contributing most 

to area emissions are seldom located in the geographic center of a cell.

POINT SOURCES

Of the major point emission sources identified in 

the board's initial emissions source inventory, many 

had closed down or substantially reduced their emissions by 1972. The initial inventory of point sources 

was located on the Level II land use and land cover 

map and their current annual levels of emission 

were verified from August 1972 board registration 

records. Other industrial, extractive, transportational, and institutional uses identified in the board's 

registration program were located on the Level II 

land use and land cover map, and the board's staff 

identified those with the greatest levels of emissions. 

In this way, 44 ^oint sources having high levels of 

emission or emissions that had persisted over long 

periods were identified as the most significant to

TABLE 3.—Sample pages of table of estimated Norfolk-Portsmouth SMSA, 1972 annual, winter 1971-72, and estimated

annual 1985 emission inventories *

Source 

No.

SIC 

code

Site 

code

Source location 

(kilometers) 

Horizontal Vertical

Scarce 

area 

(34 km)

Emission rate 

( megagrams/day ) 

SOa Part

Stack 

fcer'ght 

(meters)

Staok 

diameter 

(meters)

Exit 

velocity 

(m/eee)

Exit

temperature 

(degrees

K)

Annual 1972 

Source data, October 5, 1972

1 _ .

2

20 _ .

46 _ .

55 _ .

50

55

111

.__ 9,999

.__ 9,999

99

100

121

50

60

384.0

382.7

386.4

383.1

397.0

A nan n

4,089.0

4,676.9

4,090.1

4,086.0

0.0

0.0

0.0

6.3

25.0

0.08

18.49

0.00

0.02

0.08

ft A9

1 ^9

0.50

0.06

0.05

35.0

35.0

10.0

3.0

8.0

4.0

4.0

0.0

0.0

0.0

30.0

30.0 0.0

0.0

0.0

450.0

450.0

0.0

0.0

0.0

Winter 1971-72 

Source data, October 5, 1972

1 _ _.

2 _ .

20 __ .

46 __ .

55 __ .

50

55

111

9,999

.__ 9,999

99

100

121

50

60

384.0

3S2.7

386.4

383 1

397.0

4,090.0

4,089.0

4,076.9

4 OQQ 1

4,086.0

0.0

0.0

0.0

6.3

25.0

0.12

438.09

0.00

0.04

0.24

0.46

2.85

0.50

0.06

0.09

35.0

35.6

10.0

3.0

8.0

4.0

4.0

0.0

0.0

0.0

30.0 30.0

0.0 0.0

0.0

450.0

450.0

0.0

0.0

0.0

Estimated annual 1985 

October 6, 1972

1 __ .

2 _ _.

20 __ .

46 _ .

55 __ .

50

55

111

.__ 9,999

9,999

99

100

121

50

60

3S4.Q

382.7

386.4

383.1

397.0

4,090.0

4,089.0

4,076.9

4,090.1

4,086.0

0 0

0.0

66

6.3

25.0

0.08

13.49

0.00

0.02

0.08

0.42

1.52

0.34

0.06

0.05

35.0

35.0

10.0

3.0

8.6

4.0

4.0

0.0

0.0

0.0

30.0

30.0

0.0

0.0

0.6

450.0

450.0

0.0

0.0

0.0

1 Data from Virginia State Air Pollution Control Board I«ipVem«ntetiGB Plan, 1972.
B14 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

the area's air quality and were included in the updated point source emissions inventory (fig. 6 and 

table 3).

SEASONALITY

The Air Pollution Control Board's original inventory divided the emissions of area and point sources 

into seasonal increments. The current registration 

program does not provide seasonal or other periodic emission rates. When the staff of the board 

could determine that point sources had modified 

their winter operating patterns, the original winter 

season estimates were reduced or increased to reflect 

these changes. For the remaining point and area 

sources, however, winter emissions levels were taken 

as estimated in the original inventory.

FUTURE EMISSION PATTERNS

Air-quality planning for the Norfolk area must 

consider the impact of growth and future emission 

levels. Along with its utility for estimating current 

patterns of emissions, the land use and land cover 

information can be used to estimate emission levels 

from projected future land use and land cover patterns.

For each grid cell the rate of change between 1959 

and 1970 in Level I and II land use categories was 

determined from the graphic information provided 

by the CARETS project maps. The Southeastern 

Virginia Planning District Commission provided 

1985 population and employment projections for 

each of the SMSA jurisdictions along with estimated 

amounts of land use and land cover that would be 

required to accommodate a recommended pattern of 

future land use and land cover (fig. 7). Residential 

and commercial land use and land cover changes to 

1985 were postulated for the area by extrapolating 

past trends in land use and land cover change given 

by the pilot system and the commission's projections 

of utility and transportation installations (Henningson, Durham, and Richardson, 1972, and Wilbur 

Smith and Associates, 1969). The likelihood of a 

given area emissions estimating cell being developed 

to a given level by 1985 was estimated from this information as were standards for population density, 

zoning regulations, and anticipated building practices suggested by the commission.

It was assumed that emission levels from existing 

area sources would continue unchanged to 1985 because much of the SMSA's residential development 

is of recent origin; decreases in emissions per vehicle would be offset by an increased number of vehicles ; and small new area sources would compensate 

for the existing area emissions that have recently 

upgraded their controls or ceased emissions. Emission levels per square kilometer from residential and 

associated land uses and land cover to be developed 

by 1985 were estimated on the basis of anticipated 

space heating procedures, 1985 traffic volumes, and 

land uses to be permitted in various areas. These 

estimates, 0.01 megagrams of sulfur dioxide and 0.25 

megagrams of particulates per day/km2 were multiplied by the number of kilometers of residential 

and other land uses projected for each cell. These 

values were added to the existing amount of area, 

emissions to estimate the 1985 total area source 

emissions for each cell.

Future emission levels for the 44 point sources 

included in this study were estimated on the basis of 

control programs proposed to the Air Pollution Control Board by various firms. These control programs 

incorporate standards for levels of emissions currently required by Virginia legislation and the Air 

Pollution Control Board rules (Commonwealth of 

Virginia, 1972b and 1972c). For purposes of this 

study it was estimated that no new major point 

source would locate outside areas of existing industrial development. Table 4 gives the inventory of 

point emissions sources used in 1985 estimates.

LAND USE AND LAND COVER AND NORFOLK AREA 

EMISSION PATTERNS

Plotting the spatial distribution of area and point 

source emissions provides basic information for 

evaluating the design of air quality sampling programs and estimating the likely impact of different 

air quality control strategies. Figures 8 through 13 

show the estimated average quantity and distribution of sulfur dioxide and particulate emission in 

the Norfolk area for 1972 annual and winter 1971- 

72 periods and for an annual 1985 period. Total 

emissions by area cell, like those given in table 3, 

were converted to values per square kilometer and 

are indicated by isolines. The average of major point 

source emissions for each cell are also plotted. The 

similarity between sulfur dioxide and particulate 

emission patterns in these figures reflects the emission of both pollutants by most sources throughout 

the Norfolk area. Because of the area's space heating traffic, and industrial characteristics, particulate 

matter is emitted at higher levels than sulfur dioxide from all but a few point sources.

In these figures the pattern of high annual emission from point and area sources clearly reflects the 

concentrations of industrial, commercial, and old,
76°15' W

EXPLANATION 

o Area centroids 

28 Point sources 1 

1 Keyed to table 3

370 E.

4085 N.

36°55' N— C-2 

Portsmouth' A

/

\2

-O

Chesape;

39

I

3i

h

12 °

29

2 ox

? /C0

N^

XNlO

r*A\

lAo^JaoCvT

Til

I /'

42

k.

rii

^2o

11

116

17

^-

ake

Norfolk

76°00' W

Xi

^5> o!9

18

^_..

"•\. — —v

,A

-36°55r N

76°15' W 76°00' W UTM 42

FIGURE 6.—1970 Norfolk-Portsmouth SMSA, selected point sources and centroids of area emission cells.
BIS THE INFLUENCES OF LAND USE AND LAND COVEE IN CLIMATE ANALYSIS

37© E

4090 N.

36°40' N

76°15' W 

FIGURE 7.—1970 Norfolk-Portsmouth SMSA, proposed land use and land cover, 1985.
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B17

EXPLANATION 

Land use

Low density residential

Medium density residential

High density residential

Commercial

Industrial

Open spaces, recreation

Institutional

Military

Agriculture, forest, water, or wetlands

—•—•—• City boundaries

—— — — State boundary

0 5

I I I I

10 KILOMETERS

UTM 420 E. 

76°00' W

From plan proposed by Southeastern Virginia Planning District Commission.
B18 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

AH

i

l-l 

PH
76°15' W

76°00' W

4085 N

370 E.

-36°55' N

36°40r

EXPLA

—.01—Area sources (to

Q'Oo p0int sources (to

36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 9.—1970 Norfolk-Portsmouth SMSA, estimated emissions of sulfur dioxide, winter 1971-72.
76°15'

76°00' W

4085 N

370 E

36°40' N—

EXPLA

••02—Area sources (to

81 

"•' Point sources (to

-~36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 10.—1970 Norfolk-Portsmouth SMSA, estimated emissions of sulfur dioxide, 1985.
76°15' W

76°00' W

370 E

36°55' N

4085 N.

EXPLA

—.05— Area sources (to

-.94

sources (t

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 11.—1970 Norfolk-Portsmouth SMSA, estimated emissions of particulates, 1972.
76°00' W

-36"55' N

36°40' N

EXPLA

— .08 — Area sources (ton

Point sources (ton

--36°40' N

v-4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 12.—1970 Norfolk-Portsmouth SMSA, estimated emissions of particulates, winter 1971-72.
76°15'

76°00' W

370 E.

4085 N.

36°40' N

EXPLAN

—.05—Area sources (tons

02

~" Point sources (ton

A-4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 13.—1970 Norfolk-Portsmouth SMSA, estimated emissions of particulates, 1985.
B24 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

TABLE 4.—Point sources included in ««> dignsion modeling 

of Nerf&lk-P#rte*utmtk SMSA

Identification No. 1 Name of source 2

1__Naval Air Rework Facility, Norfolk Naval 

Air Station.

2____Naval Public Works Center, Norfolk Naval 

Air Station.

3___Naval Supply Center, Norfolk Naval Air 

Station.

4____Sheller Globe Corp.

5______Naval Amphibious Base.

6____Norfolk Regional Airport.

7___Fort Story.

8__-.Tidewater Community College, Frederick 

Campus.

9____City of Norfolk Incinerator.

10____Owen Pattern Foundry and Manufacturing Co. 

11___Colonial Block Corp. 

12______Georgia Pacific Corp.

13_____Dixie Manufacturing Co.

14___U.S. Naval Hospital. 

15______City of Norfolk Incinerator.

16___Ames and Webb, Inc.

17____Southern Block and Pipe.

18______Contractors Paving Co.

19___Asphalt Roads and Materials.

20____Richard Foundry Corp.

21___Colonna's Shipyard, Inc.

22____Ford Motor Co.

23____Norfolk Redevelopment and Housing

Authority.

24___Southland Cork Co. 

25_—-.-Atlantic Creosoting Co. 

26______Portsmouth Paving Corp.

27___Norfolk Veneer Mills, Inc.

28____Finley Paving Corp.

29____-City of Portsmouth Incinerator.

30____Norfolk Naval Shipyard.

31—__-Norfolk Shipbuilding and Drydock Corp.

32____Royster Co.

33_—___Oceana Naval Air Station.

34—___Fleet Anti-Air Warfare Training Center.

35_ ___Swift Agricultural Chemicals Corp.

36____Weaver Fertilizer Co. 

37___Lone Star Industries.

38—---Southern States Coop., Inc., Fertilizer 

Division.

39—___Lone Star Industries.

40——Naval Ammunition Depot, St. Julien Creek.

41 ____Solite Masonry Units Co.

42—---Intercoastal Steel Corp.

43 — ___Virginia Electric and Power Co.

44—___Smith-Douglass.

1 Identification numbers keyed to table 3 and figure 6.

3 Selection of sources based on high levels of emission identified in

Air Pollution Control Board, July and August 1972.

dense residential activities in central Norfolk and 

Portsmouth (figs. 8 and 11). To the east, lower emissions reflect the combination of low-density residential, commercial, transportation, and industrial 

land use and water and agricultural land use and 

land cover. The extent of high area source emissions 

surrounding central Norfolk and Portsmouth is 

larger in winter due to increased space heating in 

medium- and low-density residential areas (figs. 9

and 12), but otherwise the patterns of winter emissions reflect annual patterns.

The estimated 1985 annual emission patterns 

(figs. 10 and 13) show the projected urban expansion into nonurbanized area. Because of the attraction of waterfront property, the Southeastern Virginia Planning District Commission anticipates that 

Atlantic Ocean and Chesapeake Bay waterfronts 

will be filled by 1985.

DETERMINING SPATIAL DISTRIBUTION PATTERNS 

OF AIR QUALITY

To evaluate Norfolk area control strategies, patterns of emission need to be related to actual levels 

of pollutant (sulfur dioxide and particulates) concentration determined by air quality sampling 

throughout the region.

The air-quality sampling stations shown in figure 

14 were established by October 1972; the majority 

of them had been in operation less than 1 year 

(Commonwealth of Virginia, 1972b). Figure 14 

suggests that their spatial distribution does not reflect the diversity and density of land uses and land 

cover impacted by sulfur dioxide and particulates. 

Because reliable sampling information was not 

available, estimates of the areawide dispersion and 

concentration of sulfur dioxide and suspended particulates were made.

ESTIMATING POLLUTANT DIFFUSION PATTERNS

The proiblem of estimating pollutant dispersion 

and the characteristics of a pollution plume is 

couched in the exercise of describing the turbulent 

motion of air. As turbulence is best described at 

this time by probabilistic means, the most widely 

used and successful model for characterizing pollution dispersal is the Gaussian plume model. Wanta 

(1968, p. 217) outlined this model in simple terms,

the mass of pollutant emitted from a continuous point source 

moves downwind at a constant speed, at the same time 

spreading horizontally and vertically in such fashion that 

while the mass in any cross section remains constant, the 

distribution of concentration of pollutant in the cross section 

along either the horizontal or vertical direction is bell-shaped, 

i.e., normal or Gaussian. The standard deviations of these 

two normal distributions are adjustable and increase with 

distance and time; they are diffusion coefficients or simple 

functions of them. The standard deviation of the horizontal 

profile of pollutant concentration is generally much greater 

than that of the vertical. Allowance can be made for the 

presence of nearby reflecting planes such as the ground or an 

elevated ideal temperature inversion. Modifications for instantaneous source and other geometries are also available.

Wanta (1968) presents an excellent outline of urban air pollution diffusion models, especially sum-
76°15' W

76°00' W

370 

4085 N.

- -36°55' N

36°40' N—

EXPLA

P Suspended 

S Sulfur diox

Population 

76°15' W 76°00' W UTM 420 E.

FIGURE 14.—1970 Norfolk-Portsmouth SMSA, location of air-quality sampling stations, October 1972.
B26 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

marizing Smith (1961), Pooler (1961), Turner 

(1964), Clarke (1964), Koogler and others (1967), 

and Miller and Holzworth (1967) ; all of these models are variations of the basic Gaussian model.

Turner (1970) has published a workbook for calculating a numerical solution for pollutant concentration and diffusion, and Forsdyke (1970) has 

briefly summarized meteorological factors concerned 

with the Gaussian model.

Hanna (1971) has described a simple but physically realistic model for estimating- pollutant concentrations resulting from area source emissions in 

a city. Pollutant concentrations for the surface are 

directly proportional to local area source strength 

and inversely proportional to wind speed. The model 

is simple, yet results appear to compare favorably 

with more complex diffusion models.

Investigators have also worked with other types 

of models. Getis and Jackson (1971) have constructed a model to determine the probability of a 

specified area being- polluted by a specified number 

of sources. This model is based on a Poisson distribution function that is used to generate areal pollution zones. Lamb (1971) and Egan and Mahoney 

(1971) have used a deterministic approach in estimating pollution dispersal; the general method is to 

solve the system of partial differential continuity 

equations with suitable initial and boundary conditions. This approach is much less tractable than the 

Gaussian model and, accordingly, less popular. Egan 

and Mahoney (1972) have also discussed the use of 

specified source models and box models for estimating pollution dispersal.

All of the models mentioned above can be calculated for either point or area source emissions or 

both. With a Gaussian model, the nature of the emission source and its strength are primary factors.

Work has begun on the development of receptor 

models based on either Bayesian statistics or on 

some other probability function that can characterize pollution concentration only in terms of receptor information. In the future this type of model 

may find wider applications than the source models 

now in use (U.S. Environmental Protection Agency, 

1974).

MODEL USED TO ESTIMATE NORFOLK AREA AIR 

QUALITY

The Martin-Tikvart model, entitled the Air Quality Display Model (AQDM), is the diffusion model 

used in this analysis. It has been used by EPA to 

assess air quality standards for the designated air 

control regions in the United States (U.S. Environmental Protection Agency, 1970). The basic equation in the model is a slightly modified Gaussian 

diffusion equation for an elevated, continuously 

emitting point source. The calculations have been 

adjusted to estimate long-term average concentrations for multiple polluting sources, both point and 

area, under a variety of meteorological conditions.

Wind direction in the AQDM is assumed to be 

specified on a 16-point compass, corresponding to 

22.5° sectors. For an averaging period, all wind 

directions within a given sector are assumed to occur with equal chance.

Hourly data are used to calculate the joint frequency distribution of meteorological conditions. 

Wind speed is grouped into six classes and the nature of the atmospheric stability into five classes. 

These factors are discussed in a following section 

and relate directly to characteristics of the Norfolk 

area. For a particular combination of meteorological 

conditions at any receptor point at distance (p) 

within a given distance, the ground-level concentration (X; g/ms ) due to a point source with emission 

rate (Q; g/s) is: X(p,l,S) ={2Q[(2»)%^(p,l)/» 

(S)(27rp/16)]exp[-i/2 (ff/^(p,D) 2 ]} where M (S) 

is wind speed in meters per second representative 

of a wind speed class (S), H is effective stack height 

in meters, and <^(p,l) is the standard deviation of 

the vertical concentration distribution (Gaussian) 

for a ground-level emission in meter. This expression is a function of the distance (p) from the 

source and the atmospheric stability class (1). The 

model also includes a time-delay function for S02 , 

for which the half life used in this exercise was 4 

hours.

For each receptor location, the model sums the 

effect of all sources over a wide range of meteorologic conditions. Modifications are made for qz under certain conditions, and effective stack height 

(H) is determined in the usual manner. For more 

detailed information on these two aspects see Martin 

(1971). Area sources in the model are treated as a 

virtual point source at some distance upwind from 

the center of the area source (fig. 15).

In summarizing, the input data consist of pollutant emission source, source configuration and location, receptor location, and the meteorological information. Output data are listed for each grid and 

nongrid receptor specified. The output results are 

the arithmetic mean of ground level concentration 

of either SO2 , or geometric means of particulates, 

or both; additional information is supplied for five 

user-selected receptor sites of the five maximum 

receptor sites. The contribution of a given point or
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B27

A

X

B

Virtual point 

source location

Wind 

direction

O Receptor

22.5° sector

Virtual point source 

location for A'

' = Area "seen" by 

receptor 2

O Receptor 2

^

Source area A

Wind 

direction

O Receptor 1

FIGURE 15.—Treatment of point (A) and virtual point for area source (gandC) diffusion patterns

in air-quality display model (AQDM).

area source to each receptor is indicated as a percentage of the total concentration on the receptor 

grid, and this information is displayed by the construction of an isopleth map of the pollution distribution. The receptor grid used in the Norfolk area

consisted of 2.5-km2 cells; the nature and rationale 

for this grid size will be discussed in a later section. 

Calibration of the AQDM for a particular area 

begins with the measurement of concentration values—3 to 100 values for each pollutant studied—at
B28 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

specified measuring stations. A least-square regression analysis is conducted between the measured 

(independent variable) values of pollutant concentration.

If the regression line adequately describes a 

"good" association between measured and observed 

values, the model output results are adjusted at each 

receptor point according to the parameters calculated from the regression equation. The "goodness" 

of the association is determined by the calculation 

of a correlation coefficient that is compared to a 

maximum theoretical value that could have resulted 

due to chance. When the correlation is termed nonsignificant, the calculated concentration will be output without adjustment. Because of the lack of sample data, this correlation procedure was not utilized 

in this work.

Some caution must be expressed concerning the 

use of this type of model and the assumption upon 

which it is based: (1) The model was originally 

developed to represent plume behavior from actual 

point sources over open, flat terrain for distances of 

less than a few kilometers; the Norfolk area approximates this situation fairly closely, as it is located 

on a peninsula with little relief and the buildings 

are predominantly one-story residential complexes. 

(2) The surface meteorological data often provide 

poor characterization of the vertical nature of the 

lower atmosphere. (3) Emission inventories input 

to the AQDM are subject to compoundable errors 

in that the model uses annual average emission figures that may be influenced by significant diurnal 

and seasonal variation (TRW Systems Group, 1969, 

p. 2-6, 2-7 and A-3.

NORFOLK AREA AIRFLOW CHARACTERISTICS

The meteorological factors that influence the dispersion of pollutants are wind speed and atmospheric stability, that is, the observed lapse rate. The 

effects of turbulence are included in both of these 

factors. Concentration at any point downwind is 

inversely proportional to wind speed, since increasing the wind speed increases the volume into which 

the pollutant is dispersed for a given time period. 

The observed lapse rate determines whether vertical motion in the atmosphere will be enhanced or 

suppressed, and thus determines the rate of dispersion of pollutants. Both of these parameters are 

used as inputs to the AQDM.

Stability of the atmosphere is classified into five 

categories based on the works of Pasquill as found 

in Turner (1964), who states:

* * * Stability near the ground is dependent primarily upon 

net radiation and wind speed. Without the influence of clouds, 

insolation (incoming radiation) during the day is dependent 

upon solar altitude, which is a function of time of day and 

time of year. When clouds exist, their cover and thickness 

decreases incoming and outgoing radiation. In this system 

insolation is estimated by solar altitude and modified for 

existing conditions of total cloud cover and cloud ceiling 

height. At night, estimates of outgoing radiation are made 

by considering cloud cover * * *. The stability classes are 

(A) extremely unstable, (B) moderately unstable, (C) slightly unstable, (D) neutral, and (E) slightly stable.

The seasonal and annual wind distribution (direction and speed percentages) and frequency of Pasquill stability classes have been calculated by the National Climatic Center, Asheville, N.C., (Job 13599) 

for Station No. 13750, Norfolk, Va., Naval Air Station. On the basis of 24 observations a day from 

December 1966 to November 1971, it was determined from Slade and others (1961), that the Naval 

Air Station (NAS) site gave good representation 

of the annual and and winter wind rose for the 

greater Norfolk area. This representativeness and 

the hourly measurements were the overriding considerations in the choice of Norfolk NAS rather 

than one of the other three meteorological stations 

in the area. A slight discrepancy exists between Norfolk NAS and Oceana NAS during the winter afternoons—a small increase in the wind direction from 

the east and southeast for Oceana NAS, which is located east of the Norfolk NAS and close to the Atlantic Ocean.

On an annual basis the stability frequency is as 

follows: 6 percent-B, 12 percent-C, 47 percent-D, 

and 32 percent-E, which accounts for 97 percent of 

all stability occurrences (fig. 16). The greater frequency of D and E stability classes is an apparent 

anomalous condition for an urban setting. Stability 

class C usually predominates in urban areas becauses the cityspace provides greater surface roughness, which increases mechanical turbulence, and 

because the higher temperature of cities versus 

rural areas (the urban heat-island effect) produces 

more thermal turbulence. The Norfolk area has more 

instances of stable conditions because of its geographic setting. The Norfolk region is situated on a 

peninsula where the abjacent water areas decrease 

both the thermal turbulence caused by the urban 

heat-island effect and mechanical turbulence. The 

latter occurs because the water has a lower surface 

roughness (Van der Hoven, 1967).

The wind direction for the annual period is as 

follows, in decreasing percentages based on 16 points 

of the compass: (1) 10.5 percent-SSW; (2) 9.1 

percent-S, and 9.1 percent-N; (3) 7.5 percent-W;
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B29

N

9.1%

7.1%

5.1%

3.7%

4.0%

7.5%

5.7%

10.5%

A = Extremely unstable 

B = Moderately unstable 

C = Slightly unstable 

D = Neutral 

E = Slightly stable

7.1%

5.8%

Data supplied by: 

National Climatic Center 

National Oceanic and

Atmospheric Administration 

Asheville, North Carolina

FIGURE 16.—Annual stability wind rose, December 1966-November 1971, Norfolk Naval Air Station.
B30 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

8.1%

4.7%

3.3%

9.1%

7.5%

A = Extremely unstable 

B = Moderately unstable 

C = Slightly unstable 

D = Neutral 

E = Slightly stable

Data supplied by: 

National Climatic Center 

National Oceanic and

Atmospheric Administration 

Asheville, North Carolina

FIGURE 17.—Winter stability wind rose, December 1966-November 1971, Norfolk Naval Air Station.
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B31

and (4) 7.1 percent from both E and NNE (fig. 

16). The remaining directions each account for less 

than 7 percent. The lowest value is 3 percent from 

the east southeast. The highest average wind speed 

was from the north and north northeast at 10.2 

knots. A 6 percent incidence of calm was reported. 

The winter season (Dec.-Jan.-Feb.) displays 

slight variations from the annual situation. The stability class percentages are: (1) 7 percent-C, (2) 

58 percent-D, and (3) 31 percent-E (fig. 17). A 

greater percentage of more stable conditions exists 

during the winter, as seen in the increase of the 

class D and the decrease of the class C. As compared 

to the annual period, the wind directions in winter 

turn more to the north and west: (1) 13.3 percent-N; (2) 11.2 percent-W; (3) 9.1 percenl^SSW; 

(4) 8.1 percent-NNE; (5) 7.8 percent-NNW; (6) 

7.5 percent-S; and (7) 7 percent-WNW. The remaining directions each are less than 7 percent; the 

lowest is 1.6 percentf rom the east southeast. The 

highest wind speeds during the winter, 10 to 11 

knots, all come from the northwest quadrant. The 

lowest average speed was 5 knots from the southeast. Six percent calms were reported for the winter 

period: (1) the greatest frequency of calms for a 

given hour occurred at 2200 h; (2) the greatest 

frequency of low-level inversion occurred at 0300- 

G.m.t. when the wind direction was from the south 

southwest, with fairly comparable percentages 

through to the northwest; (3) the seasonal frequency of precipitation by wind direction was primarily from the north northeast and north and secondarily from the south southwest and north northwest, but only 11.5 percent of total yearly rainfall 

occurred during the winter season. Holzworth 

(1964) gives an afternoon mixing depth of 600 m 

for Norfolk. This mixing depth appears to be a very 

conservative estimate, as Holzworth has recently updated his analysis to an annual afternoon mixing 

depth of 1200 m for the Norfolk area (Holzworth, 

1972). This revised value was not available at the 

time this experimental study was undertaken.

SELECTION OF GRID PATTERNS FOR ESTIMATING 

POLLUTANT CONCENTRATIONS

Given this diffusion-estimating procedure, atmospheric data, and the emission inventories described 

earlier, current and future levels of sulfur dioxide 

and particulate concentrations could be calculated 

for locations throughout the Norfolk area. To relate 

this estimated pollution pattern to patterns of land 

use and land cover and selected points for air quality 

sampling, a grid for estimating pollution concentration for receptors was established. Although the 

land use and land cover information had a 4 ha 

minimum mapping unit, the spatial resolution of 

this grid was constrained by the estimating of area 

source emission inventories at a resolution of 6.25 

km2 or larger. To remain within the precision of the 

emission inventories and the capabilities of the estimating model itself, researchers determined that 

attempts to estimate pollution concentration at resolutions larger than 6.25 km2 were not warranted.

From the location of point and area source emissions shown in figure 6 and the location and density 

of land uses and land cover to be impacted, a regular 

receptor grid of 2.50 km2 cells was selected and 

superimposed on the area source emissions estimating grid at approximately the center of the 6.25 

km2 cells (fig. 18). Because of the distance decay 

function in the model, locating the receptor points 

coincident with emission centroids for point or area 

sources would have resulted in estimated levels of 

pollution much higher than would be expected to occur as pollutants diffuse over the entire area of a 

cell. Alternatively, to have randomly offset the grid 

from area or point emission sources would have resulted in many clusterings of receptor points, leaving large areas unevaluated. The 2.50-km density 

of receptor points was extended into the 10-, 25,- 

and 100-km2 grid cells to estimate how these rapidly 

developing lower density cells are currently being 

impacted. In addition, a set of receptor points was 

specifically placed coincident with the location of 

existing air quality sampling stations indicated in 

figure 14. The same grid was used for future estimation.

NORFOLK LAND USE AND LAND COVER AND

ESTIMATED AIR POLLUTANT CONCENTRATION

PATTERNS

On the basis of the estimated emissions inventories and receptor grid, the air pollutant concentration estimating program, ADQM, of the Air 

Quality Implementation Planning Program was used 

to estimate 1972 annual, 1971-72 winter, and 1985 

annual concentrations of sulfur dioxide and suspended particulates throughout the Norfolk area 

(U.S. Environmental Protection Agency, 1970). 

Figures 19-24 present the estimated spatial patterns. Table 5 is an example of the data produced 

by the AQDM program used to produce these figures. Table 6, another example of the program's 

output, gives point and area source contributions 

to receptor points having high concentrations and 

suggests emission reductions necessary to achieve
76°15' W

76°00' W

36°55' N 

4085 N.

36°55' N

36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 18.—1970 Norfolk-Portsmouth SMSA, pollution concentration estimating points.
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B33

TABLE 5.—Estimates of concentration of pollutants over 

receptors

[Region: Norfolk area (annual). Date: October 5, 1972] 

Receptor concentration data

Receptoi

No.

1_

2_

3__

4 _

5__.

6__

7 _,

8 _

9 _.

10-

11 _

12

13_

14 _

15 _.

16_

17_

18—

19 _

20 _

21 _.

22_ . 23_

24_

25

26__

27_

28_

29_

30—

31_

32_

33_

34 _

35.

36__

37 _

38 _

39_

40 _

Receptor location 

r (kilometers)

Horizontal

__ 371.2

_ -371.2

. —371.2

__ 371.2

. —371.2

. __ 371.2

__ _371.2

__ 371.2

— _371.2

. __ 371.2

__ 371.2

— .371.2

_ _373.7

— _373.7

_ __ 373.7

_ —373.7

_ —373.7

__ 373.7

_ 373.7

__ 373.3

- _373.7

. _373.7

- —373.7

— _373.7

_ 376.2

- _ 376.2

_ _ 376.2

__ 376.2

__ 376.2

— _376.2

__ 376.2

_ —376.2

_ _ 376.2

_ _376.2

__ 376.2

__ 376.2

__ 378.7

_ —378.7

_ 378.7

_ _378.7

Vertical

4,061.2

4,063.7 

4,066.2 

4,068.7 

4,071.2 

4,073.7 

4,076.2 

4,078.7 

4,081.2 

4,083.7 

4,086.2 

4,088.7 

4,061.2 

4,063.7 

4,066.2 

4,068.7 

4,071.2 

4,073.7 

4,076.2 

4,078.7 

4,081.2 

4,083.7 

4,086.2 

4,088.7 

4,061.2 

4,063.7 

4,066.2 

4,068.7 

4,071.2 

4,073.7 

4,076.2 

4,078.7 

4,081.2 

4,083.7 

4,086.2 

4,088.7 

4,061.2 

4,063.7 

4,066.2 

4,068.7

Expected arithmetic mean 

(mierograms/eubic meter)

SO2

5.2 

6.9

6.6 

6.8 

6.7 

6.2 

5.6 

5.8 

6.1 

6.8 

8.0 

5.2 

5.5 

7.2 

7.8 

8.4 

8.1 

7.1 

7.3 

7.3 

7.5 

7.3 

7.7 

6.2 

6.5 

7.5 

9.6 

11.3 

10.3 

8.6 

9.9 

9.6 

9.9 

9.2 

8.9 

7.6 

8.3 

9.7 

11.4 

13.9

Part

8.8

10.1 

11.8 

14.0 

16.5 

19.4 

20.4 

19.6 

19.4 

18.7 

17.6 

16.8 

9.2 

10.6 

12.4 

15.5 

18.3 

22.4 

24.1 

22.4 

23.0 

21.7 

20.5 

19.7 

9.6 

11.3 

13.6 

17.2 

21.5 

27.0 

29.6 

28.2 

28.2 

26.4 

24.9 

23.2 

10.4 

12.1 

15.0 

19.7

desired air quality. The program also produces 

estimate of the contribution of each point and 

a source at selected receptor points (table 7). 

iluation of control strategies and implementation

plans is based on these data and their relation to 

specific patterns of Norfolk area land use and land 

cover.

Although the area's air-quality sampling program 

was not yet fully operational, the range of annual 

and winter sulfur dioxide and suspended partieulate 

samples drawn at selected stations are shown in figures 19, 20, 22, and 23 (Commonwealth of Virginia, 

1972b). These initial values are based on a limited 

number of samples, many of which were subject to 

modification in sampling procedures during the 

startup period of the sampling system. These measured pollution values, however, generally reflect the 

estimated concentrations of sulfur dioxide and suspended particulates, suggesting that these model 

estimates are not unreasonable given the assumptions built into (1) the emissions inventories, and 

(2) the use of an airflow pattern for the Norfolk 

Naval Air Station. The large discrepancy between 

1972 sampled and estimated levels for the sampling 

station in cell 103 appears to result from extensive 

construction occurring immediately adjacent to the 

sampling station during the previous year and by 

the station's proximity to an expressway and an 

asphalt plant, all of which tend to be averaged out 

in the cell's area emissions inventory.

The emissions inventory for particulates included 

both settleable and suspended material. Using Virginia State Air Pollution Control Board registration and initial inventory records, no method could 

be devised for estimating the percentage of suspended particulates in total emission and no definite 

information could be obtained on the rate at which 

settleable materials dropped out from different types 

and heights of sources. Most settleable materials, 

however, are assumed to drop out within a distance 

of 2 km from source locations. The initial operation of background sampling stations within the

6.—Example of estimates of point and area source contributions and recommended reduction programs for

selected receptor points

[Region: Norfolk area (annual). Date: October 5, 1972. Particulate pollutant concentrations above standard of 75.00 /itg/m 8 ]

Pollutant concentration (micrograms per cubic meter)

Receptor

No.

Arithmetic 

mean 

concentration

315.7824

164.3243

155.5200

125.3193

104.8958

92.5805

89.6757

83.1145

77.5693

75.7201

75.2046

Excess above 

air quality 

standard

240.7824 

89.3243 

80.5200 

50.3193 

29.8958 

17.5805 

14.6757 

8.1145 

2.5693 

.7201 

.2046

Contribution 

from point 

sources

306.8246 

148.9439 

150.3055 

114.4099 

94.9697 

88.0405 

53.5763 

80.0613 

69.7026 

60.7036 

60.2716

Pollutant reduction (percent)

Contribution 

from area 

sources

8.9579 

15.3804 

5.2144 

10.9095 

9.9262 

4.5400 

36.0994 

3.0531 

7.8668 

15.0165 

14.9330

Necessary 

for point 

sources

78.4756 

59.9718 

53.5709 

43.9816 

31.4793 

19.9687 

27.3922 

10.1353 

3.6861 

1.1862 

.3395

Necessary 

for all 

sources

76.2495 

54.3586 

51.7747 

40.1529 

28.5005 

18.9894 

16.3653 

9.7630 

3.3123 

.9510 

.2721
B34 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

TABLE 7.—Estimates of total contribution of specific sources to selected receptor estimating points, Norfolk-Portsmouth

SMSA, 1972 annual

[Region: Norfolk area (annual). Date: October 5, 1972. Source contributions to five selected SO2 receptors in microgram® per cubic meter]

Source 

No.

1

2

3 _ _ _ _

4

5 _ _ __ .

6 _ _ .

7

8 _ _ __ .

9 _ __ _.

10 _ __ _ .

11 _ __

12 _ _ _ .

13 _____ .

14 ___ _.

15 __ __ .

16 __ __ _.

17 ___ _.

18 __ - -.

19 _ _ _.

20 _ __ _ .

21 _ _

22

23 _ _ ___ .

24 __ __.

25 _ __ .

26 _ _ __ .

27 __ _ _ .

28 ______ .

29 ___ __.

30 ____ _.

31 ___ _ __.

32 _ _ _ _.

33 ____ ___ .

34 _ __ .

35 ___ ____ .

36 ______ _ .

37

38 _____

39 __ _ .

40 _ _ _ _ .

Receptor = 233

Q

0.0107

1 7939

9499

.0605

8777

.2271

.0110

.0516

3.3192

.0725

.0115

0994.

.1452

1.1209

.0905

.0332

.0316

.0022

.0351

.0000

.0107

.0854

.0117

.0000

.1492

.0917

.2050

.0099

.0966

.0086

.2368

. _ 1.2355

.0704

.0194

.4714

.0041

. _ .1352

. _ .0000

. _ .0126

.0052

0.04 

6.39 

.90 

.22 

3.25 

.84 

.04 

.19 

12.31 

.27 

.04 

.08 

.54 

4.16 

.34 

.12 

.12 

.01 

.13 

.00 

.04 

.32 

.04 

.00 

.55 

.34 

.76 

.04 

.36 

.03 

.88 

4.58 

.26 

.07 

1.75 

.02 

.50 

0.00 

.05 

.02

Receptor — 234

0.0051

.6735 

.0755 

.0185 

.6777 

.1657 

.0103 

.0234 

.0758 

.0127 

.0089 

.0164 

.0634 

1.9298 

.5816 

.1525 

.1655 

.0057 

.0955 

.0000 

.1394 

.3089 

.0341 

.0000 

.2796 

.1114 

.4723 

.0158 

.0772 

.0182 

.8188 

3.4851 

.1405 

.0360 

.9244 

.0077 

.2693 

.0000 

.0104 

.0089

0.01 

1.85 

.21 

.05 

1.86 

.46 

.03 

.06 

.21 

.04 

.02 

.05 

.17 

5.30 

1.60 

.42 

.45 

.02 

.26 

.00 

.38 

.85 

.09 

.00 

.77 

.31 

1.30 

.04 

.21 

.05 

2.25 

9.58 

.39 

.10 

2.54 

.02 

.74 

.00 

.03 

.02

Receptor = 236

0.0014

.2339 

.0246 

.0060 

1.0398 

.1149 

.0222 

.0110 

.0154 

.0013 

.0017 

.0037 

.0072 

.1090 

.0091 

.0141 

.0153 

.2631 

5.5539 

.0000 

.0023 

.0461 

.0069 

.0000 

.0334 

.0170 

.0486 

.05§8 

.0132 

.0018 

.0677 

.2939 

.4238 

.0793 

.1822 

.0016 

.0434 

.0000 

.0044 

.0014

0.01 

1.55 

.16 

.04 

6.89 

.76 

.15 

.07 

.10 

.01 

.01 

.02 

.05 

.72 

.06 

.09 

.10 

1.74 

36.80 

.00 

.01 

.31 

.05 

.00 

.22 

.11 

.32 

.39 

.09 

.01 

.45 

1.95 

2.81 

.53 

1.21 

.01 

.29 

.00 

.03 

.01

Receptor = 239

0.0030

.4769 

.0357 

.0087 

.2863 

.0505 

.0064 

.0143 

.0252 

.0021 

.0018 

.0051 

.0116 

.1954 

.0153 

.0126 

.0128 

.0033 

.0444 

.0000 

.0042 

.0484 

.0073 

.0000 

.0970 

.0418 

.1551 

.0117 

.0249 

.0047 

.2083 

.9206 

.1553 

.0527 

2.5800 

.0212 

.3730 

.0000 

.0147 

.0059

0.02 

2.91 

.22 

.05 

1.75 

.31 

.04 

.09 

.15 

.01 

.01 

.03 

.07 

1.19 

.09 

.08 

.08 

.02 

.27 

.00 

.03 

.29 

.04 

.00 

.59 

.25 

.95 

.07 

.15 

.03 

1.27 

5.61 

.95 

.32 

15.73 

.13 

2.27 

.00 

.09 

.04

Receptor = 245

0.0034

.5247 

.0434 

.0107 

.3767 

.0716 

.0077 

.0160 

.0316 

.0031 

.0027 

.0061 

.0153 

.2715 

.0255 

.0204 

.0211 

.0042 

.0616 

.0000 

.0086 

.0909 

.0155 

.0000 

.1600 

.0603 

.2612 

.0149 

.0321 

.0075 

.5857 

1.8194 

.1823 

.0537 

4.1378 

.0256 

1.0359 

.0000 

.0135 

.0144

0.01 

1.91 

.16 

.04 

1.37 

.26 

.03 

.06 

.12 

.01 

.01 

.02 

.06 

.99 

.09 

.07 

.08 

.02 

.22 

.00 

.03 

.33 

.06 

.00 

.58 

.22 

.95 

.05 

.12 

.03 

2.13 

6.63 

.66 

.20 

15.08 

.09 

3.78 

.00 

.05 

.05

Norfolk area suggested that a suspended particulate 

background level of approximately 40 /xg/m3 might 

exist because of salt spray from the ocean, erosion 

of exposed sand, and agricultural practices. This 

estimated background level of suspended particulates was not included in the model run. The near 

correspondence between levels of estimated and 

sampled suspended particulates may reflect a trade 

off between the loss of settleable particulates and 

the addition of suspended background matter in the 

sample values.

SULFUR DIOXIDE CONCENTRATIONS

Figures 19-21 show the estimated distribution of 

annual 1972, winter 1971-72, and annual 1985 sulfur dioxide concentrations and relate them to the 

distributions and levels of emissions from specific 

point sources and high employment areas in figures

8-10, and to the patterns of annual and winter airflow in figures 16 and 17. According to these estimates, the area most impacted by sulfur dioxide on 

an annual basis is the Naval Amphibious Base at 

Little Creek, in Virginia Beach east of Norfolk. This 

high estimate is partly a function of the location of 

a receptor estimating point nearly coincident with 

the point of emission. The powerplant's low stack 

suggest high levels may exist in the immediate vicinity. All other receptor locations are estimated to 

be below the national and State primary and secondary standards of 80 /xg/m3 and 60 /tg/m3 respectively. This area appears to be influenced by the 

incinerator and other area and point sources in cells 

100 and 101 (fig. 18).

Winter patterns indicated in figure 20 reflect* the 

greater frequency of winds from the northwest 

quadrant. The effect of increased space heating 

throughout central Norfolk and Portsmouth and in
76°15' W

370 E.

76°00' W

36°55' N4085 N.

-36°55' N

EXPLAN

(Sulfur dioxide concen

per cubic 

—10— Estimated val

29

D Sampled value

A34 Sampled value

1 Commonwealth of Virginia

36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 19.—1970 Norfolk-Portsmouth SMSA, estimated average concentration of sulfur dioxide, 1972.
B36 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

CQ

CQ

t

o

PH
76°15'

370 E.

76°00' W

36°55' N4085 N.

EXP

(Sulfur dioxide co

per c

——60— E

4050 N.

76°15' W 76°00' W UTM420 E.

FIGURE 21.—1970 Norfolk-Portsmouth SMSA, estimated average concentrations of sulfur dioxide, 1985.
76°15' W

370 E.

76°00' W

36°55' N4085 N.

-36°55' N

36°40'

EXPLA

(Particulate concen

per cub

—10— Estimated va

D 51 Sampled valu

A59 Sampled valu

1 Commonwealth of Vir

— 36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 22.—1970 Norfolk-Portsmouth SMSA, estimated average concentrations of particulates, 1972.
76°15

370 E.

36°55' N— 

4085 N

EXPLA

(Particulate concen

per cub

—10—Estimated va

-'36°55' N ° 29 SamPled valu

'Commonwealth of Virgin

76°15' W 76°00' W UTM 420 E.

FIGURE 23.—1970 Norfolk-Portsmouth SMSA, estimated average concentrations of particulates, winter 1971-72.
76°15' W

370 E

76°00' W

36°55' N 

4085 N

-36°55' N

EXPL

(Particulate conc

per c

——60—Es

— 36°40' N

4050 N.

76°15' W 76°00' W UTM 420 E.

FIGURE 24.—1970 Norfolk-Portsmouth SMSA, estimated average concentrations of particulates, 1985.
LAND USE AND LAND COVER INFORMATION AND AIR-QUALITY PLANNING B41

Virginia Beach near Oceana Naval Air Station (fig. 

14) is evident. The estimates suggest that primary 

and secondary standards for sulfur dioxide are exceeded throughout these high-density residential 

areas.

The estimated future pattern in figure 21 indicates that, given current control plans and rules for 

point sources, secondary and primary standards for 

sulfur dioxide may continue to be exceeded in central Norfolk and in the Little Creek area to the 

east. Elsewhere, anticipated future levels and patterns of sulfur dioxide emissions from the development of residential and other area sources are not 

expected to seriously deteriorate the region's air 

quality.

SUSPENDED PARTICIPATE CONCENTRATIONS

Figures 22-24 show estimated distribution of annual 1972, winter 1971-72, and annual 1985 suspended particulate concentrations. Patterns of high 

concentrations for particulates are broader than for 

sulfur dioxide. This reflects the more ubiquitous 

contribution to particulate emissions from construction and general industrial and commercial activities throughout the Norfolk area (figs. 5, 6, and 

11-13).

In view of the problem of mixing settleable and 

suspended particulates in the estimated emission 

inventory, these particulate patterns suggest that 

the national and State primary and secondary 

standards of 75 and 60 jug/m3 , respectively, are regularly exceeded in central Norfolk and Portsmouth. 

Current sampling values tend to confirm this, and 

it appears that point sources are the main contributors to these levels (table 4 and fig. 11).

The distribution and level of winter values reflect 

prevailing winds and increased space heating 

throughout the area. Large areas of residential land 

use and land cover in central Norfolk and Portsmouth and selected areas of Virginia Beach are estimated to be affected by concentrations above primary air quality standards.

On the basis of current control programs, 1985 

levels of suspended particulates are estimated to 

exceed secondary standards throughout central Norfolk and Portsmouth and in certain areas of Virginia Beach. Existing point sources rather than 

anticipated 1985 area sources are the major contributors in this estimate (table 4 and fig. 13). These 

estimates suggest the need for improved procedures 

for estimating and sampling suspended particulate 

emissions and natural background levels to determine whether modifications in current rules and 

implementation plans may be needed.

CONCLUSIONS

The Virginia State Air Pollution Control Board 

adopted an emissions control strategy for sulfur 

dioxide and suspended particulates in the Norfolk 

area. The implementation plan focused on local action to control point sources. Adoption of this strategy and plan were certainly reasonable, given the 

time available for planning and the information 

available on the distribution of emission sources 

and receptor land uses and land cover, the level of 

emissions, the pattern of airflows, and the measured 

concentration of pollutants.

Using the U.S. Geological Survey's land use and 

land cover information, this more detailed analysis 

of the amount and distribution of pollutants in the 

area indicates that the board's initial air quality 

planning was sound. Distribution patterns of sulfur 

dioxide and suspended particulate concentrations, 

estimated using an adequate diffusion model and the 

best available airflow data, suggest that current and 

future concentrations are most affected by point 

source emissions. Given the levels of space heating 

and mobile source emissions expected for the type of 

low-density development anticipated for the area, 

this analysis suggests that current point source control programs may not achieve required standards. 

If additional reduction is required or desired, it is 

estimated that the greatest impact could be achieved 

through emission controls affecting institutional 

(military and municipal) land uses. Change in these 

land uses and land cover would most benefit land 

users in older areas of Norfolk and Portsmouth 

(fig. 5).

This use of the uncalibrated AQDM provides the 

means for rapidly estimating impacts of alternative 

locations for new point or area emissions sources. 

Pollutant concentration levels estimated in this 

study suggest that operators of new high emission 

sources should be encouraged to locate away from 

existing areas of high pollutant concentration. Further experimentation using the model should suggest 

sizes of compatible buffer land uses and land cover 

or alternate mixes of uses that could improve diffusion characteristics.

With an adequate sampling program the AQDM 

can be calibrated to predict more accurately the 

area's pollutant concentration levels. According to 

the Virginia's State Air Pollution Control Board 

Implementation Plan (Commonwealth of Virginia,
B42 THE INFLUENCES OF LAND USE AND LAND COVER IN CLIMATE ANALYSIS

1972a), only the sampling stations in cells 70, 74, 

and 103 were planned to reflect the area's population 

concentrations. The land use and land cover and 

emission concentration distribution estimated in this 

study suggest the need for a wider dispersion of 

particulate sampling stations into cells 101, 106, and 

109, and of sulfur dioxide sampling stations into 

cells 60, 87, 99, 110, 117, 123, and 128. Sampling 

programs in these and other cells have been undertaken by the board to confirm the validity of these 

estimated concentrations and to provide a basis for 

improved estimates. Past trends in land use and 

land cover change, and future change anticipated by 

local planners, suggest the need for greater detail 

in the board's area source emissions estimating grid 

to the east and south of the existing set of 6.25 km2 

cells (fig. 5). Improvement in future area source 

emission estimates could be achieved by recording 

the types of fuels to be used in large subdivisions 

as they are developed in each grid cell. In addition, 

computerizing traffic flow data and matching it with 

the location of specific land use densities in various 

grid cells could speed up and improve the detail of 

area source emission estimates.

Given the physical setting affecting Norfolk area 

airflow and the pattern of developed and anticipated 

land use and land cover, only minor modifications 

in the current emissions control strategy and implementation plan are suggested by this study utilizing 

detailed land use and land cover information.

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•&U.S. GOVERNMENT PRINTING OFFICE: 1978 O—281-359/151