Spatial patterns of air toxins in the region
Transcript of Spatial patterns of air toxins in the region
Portland State University Portland State University
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Urban Studies and Planning Faculty Publications and Presentations
Nohad A. Toulan School of Urban Studies and Planning
Winter 2009
Spatial patterns of air toxins in the region Spatial patterns of air toxins in the region
Linda Acha George Portland State University
Vivek Shandas Portland State University
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Citation Details Citation Details Vivek Shandas and Linda George,” Neighborhood, Neighborhood, Neighborhood: Spatial Patterns of Air Toxins and Implications for Metroscape Residents and Urban Planners”, Metroscape, Winter 2009.
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Periodic Atlas of the Metroscape
Metroscape Page 13
Studies from England to Boston to Los Angles have long documented health impacts associ-ated with dirty air, but an increasing number
of researchers are connecting air quality with urban form and human health. A recent landmark study found that children living near high-traffic areas in Los Angeles suffered long-term damage to lung tis-sue and contracted respiratory illnesses.
Ironically, while each breath we take is a product of the air quality in our immediate surroundings, few studies have described how the quality of air varies within a single city. Air quality research usually fo-cuses on isolated areas or large regional scales. These preferences are partly due to the fact that extensive monitoring of air quality is expensive, which makes it is difficult to know what the conditions are for neigh-borhoods around a city.
All of this changed when the Oregon Department of Environmental Quality (DEQ) decided to under-take a highly technical modeling exercise. Known as the Portland Air Toxics Assessment (PATA), DEQ used land use, topographical, transportation, and meteorological data in the metroscape to identify the possible sources of air toxics emissions and wind patterns, and then modeled the resulting air quality for nearly 1,000 sites in the region (Figure 1). It is important to note that the points on Figure 1 do not represent actual monitored data, but a modeled pre-diction as to what could be going on in those loca-tions. Monitoring throughout the city would be cost-prohibitive.
Thanks to the efforts of DEQ, the PATA study represents one of the highest resolution datasets of modeled air quality in the nation. Additional in-formation about the methods used for creating the air pollution data can be found on DEQ’s website (http://www.deq.state.or.us/aq/toxics/pata.htm). In essence, the study documents emission and disper-sion of 12 urban air pollutants in the Portland area known to have toxic health effects.
This Atlas draws on the PATA study to explore the regional variation of air quality. The PATA study presents an extraordinary opportunity to think about how the creation of new information can help us better plan our cities, but it also challenges us to think about the impacts of the choices we make.
Air Quality
Using a series of spatial analysis techniques, we are able to take individual points of information and create a “layer” of information. The layer provides additional information by drawing on known air quality data and estimating air quality in areas for which no data exist. We use this pro-cess to create several maps of different pollutants for our region. Here, our objective is not to look at every pollut-ant in the PATA study, but to highlight a few pollutants that represent different activities in the metroscape. While the range of concentrations may vary, the protocol for determining concentrations remains the same. We have mapped the "relative cancer risk" associated with each compound (for the cumulative risk map we added the risks). Relative risk refers to how many times the modeled concentrations exceed the baseline risk. The baseline risk is 1 excess cancer in 1 million population due to lifetime exposure to a pollutant. One in a million is baseline level of concern for the EPA. For instance, a relative risk value of "6" predicts 6 excess cancers in a million population as a result of lifetime exposure to a pollutant. The values can be interpreted as the severity of impact associated to exposure to that compound at that location.
Lake Oswego
I84
I5
I405
I5
I205
Portland
Gre
Beaverton
Tigard
TualatinWest Linn
Oregon City
Milwaukie
Fairv
Sherwood
Happy Valley
Gladstone
W
King City
Durham
Rivergrove
Maywood Park
Johnson City
Figure 1
Spatial Patterns of Air Toxins in the Regionby Vivek Shandas and Linda George
MetroscapePage 14
Lake Oswego
I84
I5
I405
I5
I205
Portland
Gre
Beaverton
Tigard
TualatinWest Linn
Oregon City
Milwaukie
Fairv
Sherwood
Happy Valley
Gladstone
W
King City
Durham
Rivergrove
Maywood Park
Johnson City
BenzeneValue
High : 30
Low : 2
Neighborhood Boundary
City Boundary
UGB
Neighborhood Boundary
City Boundary
UGB
Diesel ParticulatesValue
High : 82.6511
Low : 2.7104
Lake Oswego
I84
I5
I405
I5
I205
Portland
Gre
Beaverton
Tigard
TualatinWest Linn
Oregon City
Milwaukie
Fairv
Sherwood
Happy Valley
Gladstone
W
King City
Durham
Rivergrove
Maywood Park
Johnson City
Figure 2
Figure 3
Relative Cancer Risk:Concentration of Benzene
Relative Cancer Risk:Diesel Particulates
Source: DEQ
Source: DEQ
Metroscape Page 15
We begin by looking at mobile sources of air pollution. These are pollutants from cars, trucks, trains, and boats. One
byproduct of burning fossil fuels is illustrated in Figure 2, which shows the variation in benzene concentrations for the region. As might be ex-pected, the highest concentrations (darkest areas) are along highway corridors. A second byproduct is the creation of diesel particulate matter, tiny frag-ments of carbonaceous material that are created by burning diesel fuel (Figure 3). While both benzene and diesel come from internal combustion engines, one noticeable difference is the concentration of diesel along major truck routes, including inter-states 84 and 5. Most boats also use diesel fuel, and this fact is represented along the Willamette River, which also serves as a major transportation corri-dor. The largest source of diesel particulate matter comes from non-road engines, such as construc-tion equipment.
While mobile sources of air pollution tell one sto-ry about the driving and boating we do, stationary sources tell another. In this case we look specifically at Perchlorethylene (or ‘Perc’), a toxic compound used in the U.S. since the 1940s in several indus-trial processes, including dry cleaning. Unlike mo-bile sources, concentrations of Perc do not follow freeway corridors, but discrete areas throughout the region (Figure 4). Often the high concentrations of some air pollutants can be due to specific land uses that emit these compounds—in this case, probably dry cleaning facilities.
Lake Oswego
I84
I5
I405
I5
I205
Portland
Gre
Beaverton
Tigard
TualatinWest Linn
Oregon City
Milwaukie
Fairv
Sherwood
Happy Valley
Gladstone
W
King City
Durham
Rivergrove
Maywood Park
Johnson City
Neighborhood Boundary
City Boundary
UGB
PerchlorethyleneValue
High : 2.79444
Low : 0.314995
Figure 4
Relative Cancer Risk:Concentration
of Perchlorethylene
Source: DEQ
MetroscapePage 16
Figure 5
While these three examples provide a glimpse into specific concentrations of air pollutants in the metroscape, the PATA study contains
eight other compounds, including chloroform, chromi-um, formaldehyde, nickel and others. When we add up all of these compounds, we can assess their combined con-centration. Figure 5 illustrates an overall estimated health impact from these pollutants. While roadways seem to be the primary indicator for compromised air quality, the pat-terns vary considerably around the region. With a higher density of highways occurring in downtown Portland, it
may not be surprising that downtown has some of the highest concentrations of air pollutants; however, these trends are not confined only to downtown. In fact, Figure 6 illustrates that suburban areas such as those long High-way 217 near Beaverton, and at the interchange of inter-states 84 and 205 near Gresham, are also affected by high concentrations of air pollutants. Unfortunately, one story emerging from these studies is that we cannot avoid air pollution by moving away from downtown areas. Spread-ing out seems to only bring the problem elsewhere.
Lake Oswego
I84
I5
I405
I5
I205
Portland
Gre
Beaverton
Tigard
TualatinWest Linn
Oregon City
Milwaukie
Fairv
Sherwood
Happy Valley
Gladstone
W
King City
Durham
Rivergrove
Maywood Park
Johnson City
Source: DEQNeighborhood Boundary
City Boundary
UGB
Health ImpactValue
High : 183.061
Low : 12.3303
Health Impact Score
Combined Health Impact
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SUNSET
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ELL
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MURRAY
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DURHAM
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HWY217-I5
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SUNSET-MURRAY
BALTIC
NICOLAI
SALTZMAN
I5
I5-HWY 217
CORNELL
SUNSET
HWY217
217
Metroscape
Metroscape
Beaverton
Portland
TigardHealth ImpactValue
High : 183.061
Low : 12.3303
Figure 6 Source: DEQ
Combined Health Impact: Hwy 217 Corridor
Health Impact Score
Lake Oswego
I84
I5
I405
I5
Portland
Beaverton
Tigard
TualatinWest Linn
Oregon C
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King City
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J
I5
I84
SUNSET
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PACIFIC
HALL
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CORNELL
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HWY 217
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UGHLIN
BARBUR
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STAFFORD
CORNELIUSPASS
A
FARMIN
GTON
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CANYON
39TH
SCHOLL
S FERRY
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YEON
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BOONESFERRY
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TUALATIN VALLEY
TERWILLIG
ER
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ETTE
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SIDE
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LLS
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65TH
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MARTIN
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KINGJR
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WALKER
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BURGARD
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SELLWOOD
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I5-HWY217
SUNSET-MURRAY
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MAIN
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PACIFIC
CORNELL
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HWY217
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HWY217
PORTLAND
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Figure 7
Traffic Volume and Air Quality Analysis
I205
Gr
ity
Fai
Happy Valley
adstone
Maywood Park
Johnson City
I205
MARINE
SR-14
OWELL
FOSTER
122ND
STARK
HWY 212
Y
DIVISION
REDLAND
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AIRPORT
82ND
181ST
I-205
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CLACKAMASRIVER
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ON
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I-205
Metroscape Page 19
UGB
City Boundary
Neighborhood Boundary
Traffic Volume0 - 26
27 - 54
55 - 82
83 - 110
111 - 138
Clear
Traffic Volume and Air Quality Index
Sources: DEQ, ODOT
Towards Cleaner Air
How does new and better information affect our decision making? In the case of regional air quality, we are getting a clearer sense for how concentrations of different pol-lutants vary around the region. While it may be premature to think that cars, trucks, and boats will improve the pol-lutants in their exhaust any time soon, in the short term, these variations suggest that communities in our region are disproportionately affected by poor air quality. For example, some individuals may be able to choose where they live or work based on environmental quality. Many others may not be able to choose where they live because their financial or social conditions constrain them to live and work in highly polluted areas. Such examples illus-trate that individual choice is only one part of a larger social landscape that affects communities and individuals. If this new information about air quality does not benefit society equally, then what are other options for improving the quality of life for all metroscape residents?
One option may be to think about the connections be-tween health, planning, and pubic policy. Several urban areas, including our own region, have started to look more closely at ways that public health and planning can work together to achieve more sustainable urban forms. One result is the creation of tools, such as health impact as-sessment, that allow for planning and public health agen-cies to examine how specific decisions will affect human health. To assist in these efforts, researchers are develop-ing techniques to assist decision makers in thinking about human health impacts of planning decisions. By drawing on traffic volume data and PATA, we are able to assess the importance of automobile traffic in creating high concen-trations of toxic air pollutants. Although several factors interact to affect air quality, Figure 7 illustrates the extent to which air quality is affected by freeway traffic volume. Those areas in red, orange, and yellow show a strong con-nection between air quality and traffic, while the areas in green are less linked to automobile traffic. As a result, we can use this simplified analysis to rapidly assess the effect of roadways and traffic intensity on urban air quality.
The air we breathe affects our ability to live. Through-out the early 1900s the fields of public health and plan-ning were working together to improve the conditions of people living in urban areas. Over the past several decades, the two fields have slowly drifted apart in their manage-ment responsibilities. New information such as the PATA results suggest an urgency for linking the two fields in order to achieve a collaborative public policy that can im-prove the quality of life for all residents.
Vivek Shandas is an Assistant Professor in the School of Urban Studies and Planning at Portland State University. Linda George is an Associate Professor in Environmental Science at Portland State Universtiy.