Interplay of Wind Pattern and Topography on Air Pollution Dispersion in the San Francisco Bay
Area
Understanding the influence meteorology and topography has on air pollution transport
A research proposal submitted to the Urban Studies and Planning Program
University of California, San Diego
Henry Pan
USP 186 Section A02
hepan@ucsd.edu
November 8, 2011
Abstract
This proposal outlines a research strategy to examine wind patterns on air
pollution dispersion and transport in the San Francisco Bay Area. Current
research on the relationship of wind pattern and air pollution suggests that the
meteorology and topography of an area has great impact in the dispersion of air
pollutants. This raises two fundamental problems: how can this analysis be
applied to different areas and what benefits can this analysis provide for?
Specifically, the study will do a case study of the San Francisco Bay Area region
and will also rely on wind field maps, emission inventory data, and archival
research. The research will contribute to the literature on air quality policy
making and regulations, but it will also be shared with public and private
organizations in hope that the findings will help improve air quality.
Key Terms: air quality, wind pattern, dispersion, San Francisco Bay Area
Introduction
Air pollution is a regional issue that can crosses multiple jurisdictions and effect several
regions. This dispersion of pollutant is caused by the unique wind patterns pertaining to a given
area. This study seeks to understand how the wind patterns in the San Francisco Bay Area
influences air pollution accumulation and concentration in the coastal and inland regions. In
order to understand this meteorologic phenomenon, I will examine the specific wind patterns in
the San Francisco Bay Area, point sources and area sources of pollutant emission, and the
topographic characteristics of the regions. It is important to study the relationship between wind
patterns and air pollution concentration in the San Francisco Bay Area so we can better
understand how much impact air pollution can have not only within the surrounding area of the
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source but also the outer surrounding region such as the inlands of the San Francisco Bay Area.
With this, we can make more impacting air quality policy decisions and regulations. However,
there is a limitation to this study in which this does not provide a general model that will be
applicable to other areas. It is important to recognize that each area has unique characteristics in
which one must take into consideration while conducting site analyses. Also, in a more general
sense, the results from this research may be less significant due to financial factors. The
operational costs, investments, and regulatory controls for environmental abatement may lead to
economic growth slowdown which may possibly disinterest policy-makers (Jorgenson and
Wilcoxen 1990, 337-339).
Conceptual Framework
The influence of meteorology and topography of an area on air pollution is significant in
evaluating any air pollutant concentrations. Previous studies have shown that there is a
relationship between wind patterns and air pollutants (Henry, et. al. 2002, 2237). Understanding
the effects of these two factors is important for policy-making and regulations because due to
these conditions, air pollutants can travel well far off from the point sources. Therefore, regional
efforts in mitigation must be practiced. For example, in Ventura and Los Angeles counties, a
study was conducted to trace transport and dispersion of atmospheric pollutants between the two
counties (Lamb et. al. 1978, 2089). In this site, the terrain and the wind field were specifically
analyzed to show their influence on the movement of the pollutants. As a result, it was
discovered that pollutants from the Oxnard Plain in Ventura County can travel into the inlands of
San Fernando Valley in the Los Angeles Basin. The transport of pollutants in this study crosses
multiple jurisdictions where one’s mitigation efforts may not be entirely successful due to the
failure of addressing the primary source of emission. Therefore, it is important to consider
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regional governance in air pollution legislations. Furthermore, this research will produce data
analysis for the support of regional participation in mitigation of air pollution in the San
Francisco Bay Area.
Although many jurisdictions do not practice regional governance, air pollution is
increasingly considered to be a regional issue. This issue is exemplified by a case study
conducted in the Los Angeles air basin. Here, because of the sea breeze coming from the west of
Los Angeles, the accumulated air pollutant from source areas are then transported into areas such
as Riverside and San Bernardino (Blumenthal 1978, 893). This case study provides us an
example of how wind patterns can greatly influence pollution concentrations from one area to
another. It also provides us a perspective on regional effects of air pollution where local
mitigation efforts in the inland communities would be fruitless due to the major source of
pollution coming from other municipalities. However, because there is great sensitivity of
location characteristics on the results, the same effect of the interplay of meteorology and
topography may not be assumed for the San Francisco Bay Area region. Although the results
from this study may not be directly applied to the San Francisco Bay Area region, it would
however provide us an outlook of what we may expect to occur with the wind field and
topography of the San Francisco Bay Area region.
There have also been studies conducted on the transport of air pollutants on a global scale.
One example of this is a case study on the transport of air pollution from Asia to North America.
In this study, air pollutants have been traced in the air from East Asia to North America to
discover the length of time it takes for the pollutants to be transported (Jaffe et. al. 1999, 711).
The study reported that it takes about six days for the air pollutants to travel between these two
far-stretching regions. This study demonstrates how great of an impact wind has on the
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movement of air pollutants and their transport from one region to another. However, because this
study focuses on a global scale, it is difficult to determine the full impact of the transport of air
pollutants because as the area of study increases, the situation becomes more complex. For
example, in this study, local sources of pollution must be considered in the increased
concentration of air pollutants.
Another factor that needs to be addressed is the recirculation of wind in a region that can
promote the accumulation of air pollutants. For example, in the case study of the Great Lakes
lake-breeze circulation and its effects on pollutant transport in the surrounding region, the
inversion and circulation of air from the Great Lakes has been demonstrated to have an impact in
the accumulation of air pollutants around the urbanized shoreline such as Chicago, Illinois
(Lyons and Olsson 1973, 387). This case study adds more emphasize on the impact wind
patterns may have on air pollution dispersion in a particular area. Although the physical
characteristics of the Great Lakes is not comparable to the Pacific Ocean enclosing the San
Francisco Bay Area, we can, however, use this as an example of how recirculation may affect the
concentration of air pollutants in an area since according to wind pattern makes, there are some
presence of recirculating wind patterns (Ludwig and Kehaloa1974, 31).
The meteorology and topography of the region have been demonstrated to be highly
influential in the dispersion and transport of air pollutants. However, because there is a great
dependence on the region’s landscape and characteristics, this concept must be analyzed and
evaluated for case by case scenarios. In this study, I will specifically target the San Francisco
Bay Area and analyze how the wind field in the Bay area influences air pollutant concentrations
in the region in a large scale perspective. Moreover, this study will revolve around a couple
fundamental problems: How does the wind patterns in the San Francisco Bay Area influence the
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dispersion and transport of air pollution from the coastal region into the inland regions in the San
Francisco Bay Area and why it is important to consider the interplay of meteorology and
topography in policy making and regulations.
Research Design and Methods
In order to conduct this study, a couple mechanisms will be used to collect and analyze
the data on the various aspects of the San Francisco Bay Area. One main tool that will be used in
this research is the Geographic Information System. This tool will essentially assist in analyzing
the interplay of meteorology and topography in the San Francisco Bay Area region.
In order to conduct this analysis, data on the wind patterns of the San Francisco Bay Area
must be collected. This data will be located from government agencies such as the National
Oceanic and Atmospheric Administration and non-government agencies. Data would potentially
include wind pattern changes throughout the year, spanning a few decades worth. An example of
this data has been found in a report compiled by F.L. Ludwig of the Stanford Research Institute.
In this report, maps of the most common daytime wind patterns in the San Francisco Bay Area
are provided (Ludwig and Kealoha 1974, 31). Since I have proficient skills in GIS, if GIS data is
not available, I will compile the raw data into data layers with GIS in order to spatially display
them. In addition to wind pattern data, air pollution emission data on the many municipalities
will be collected in which the estimated amount of air pollutant emitted by point sources and
their locations will be given. This information will provide a sense of where major pollutant
emitters are located and their relative position in the wind field. An example of this was found
from the Bay Area Air Quality Management District which governs the nine bay area counties in
regulating sources of air pollution. The BAAQMD provides an emission inventory of the nine
counties of the Bay Area where point sources and area sources are identified with their names,
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locations, and amount of pollutant emitted (Mangat et. al. 2010, 1-37). Further data will be
collected from the BAAQMD. If GIS-ready data is not available, the raw data will be compiled
into data layers with GIS in order to spatially display them.
This research will provide the public and government officials a spatial reference of the
interplay of meteorology and topography on transporting air pollutants in the San Francisco Bay
Area. Mostly, this will also exemplify the importance in regional policy-making practices and
the necessity of conducting case by case analysis over one-size fits all models.
Part of the data collection has already been completed. Such data include emission
inventory of 2010 and wind patterns of 1957. However, data collection will continue for about
eight more weeks. This will include data of emission inventories of previous years and of wind
pattern maps of the San Francisco Bay Area region spanning several decades. After data
collection has completed, compilation of the data collected into GIS data layers will begin in
order to create a spatial element for analysis of this research.
Expected Outcomes/Deliverables
The data from this research will assist in spatializing the effects of wind patterns on air
pollution dispersion. In analyzing the data, we will be able to see that meteorological and
topographic elements have significant impacts on the transport of airborne pollutants. In
particular, this research will illustrate the movement of air pollutants generated near the coastal
area of the San Francisco Bay Area into the inland areas causing an accumulation of pollutants in
the inland region. By the comparing between the wind pattern map layers and air quality data of
each subarea, the increase in air pollutant concentration due to the transport and dispersion by
wind patterns in the inland region will become noticeable.
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The results from this research would be applied to future policy-making decisions in
areas such as public health policies or regional air pollution mitigation plans. An example of this
is the recognition of the spatial area of influence air pollution has due to meteorological and
topographic factors and the enforcement of the reallocation of pollution tax dollars. Traditionally,
allocation of pollution tax dollars would go to the surround community of the point source
emitter (Henderson 1977, 89). However, this reallocation would also consider allocating funding
to communities where point sources are not necessarily located within their boundaries but do
cause significant pollution impact.
In addition to reallocation of tax dollars, initiatives for public health improvements may
result from the use of the results of the research. The data from this research would illustrate how
stricter health regulations can yield greater health and economic benefits (Ostro and Chestnut
1998, 94). For example, by creating heavy regulations on air pollution emission, the amount of
pollutant in general decrease; therefore, the amount of pollutant transported and dispersed would
plunge. This may ultimately yield greater health and economic benefit for the entire region.
In addressing the comments received in the draft proposal, I have elaborated more in my
arguments and comments while making my literature reviews stronger.
Bibliography
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Henry, Ronald C., Yu-Shuo Chang, and Clifford H. Spiegelman. 2002. Locating nearby sources
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direction. Atmospheric Environment. 36: 2237-2244.
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