Challenges and Recommendations for the Study of Socioeconomic
Factors and Air Pollution Health Effects
Michelle L. Bell, Marie S. O’Neill, Luis A. Cifuentes, Alfésio L.F. Braga, Collin
Green, Arize Nweke, Jorge Rogat, and Katherine Sibold with input from
participants of the International Symposium of Socioeconomic Factors and Air
Pollution Health Effects
Published in the journal Environmental Science and Policy in October 2005
Environmental Science and Policy, 8 (5):525-533
Environmental Science & Policy 8 (2005) 525–533
www.elsevier.com/locate/envsci
Commentary
Challenges and recommendations for the study of
socioeconomic factors and air pollution health effects
Michelle L. Bell a,*, Marie S. O’Neill b, Luis A. Cifuentes c,
Alfésio L.F. Braga d, Collin Green e, Arize Nweke e, Jorge Rogat f, Katherine Sibold g
with input from participants of the International Symposium of
Socioeconomic Factors and Air Pollution Health Effects
a
Yale University, School of Forestry and Environmental Studies, 205 Prospect St., New Haven, CT 06511, USA
b
University of Michigam, School of Public Health, Ann Arbor, MI, USA
c
Catholic University of Chile, Santiago, Chile
d
Laboratory of Experimental Air Pollution, University of São Paulo Medical School and Environmental Pediatrics Program,
University of Santo Amaro Medical School, São Paulo, Brazil
e
National Renewable Energy Laboratory, Washington, DC, USA
f
UNEP Risoe Centre, Energy, Climate and Sustainable Development, Denmark
g
U.S. Environmental Protection Agency, Washington, DC, USA
Available online 24 August 2005
Abstract
Persons with lower socioeconomic status (SES) may face higher risk from polluted air. This disproportionate burden may result from
elevated exposure, due to proximity to roadways or indoor air pollution from burning of biomass, and from differences in nutrition and access to
health care, among other factors. Several studies have explored this topic, however, there remain many unanswered questions. Research on how
SES affects the relationship between air pollution and health faces challenges including the choice and interpretation of SES indicators;
distinguishing indicators that describe the present state and those that describe historical conditions; the correlation between SES indicators and
other variables; differential diagnosis and use of health care services based on SES; and varying perceptions of health. This paper summarizes
these and other challenges and provides recommendations for how to move this research forward. Recommendations relate to what geographical
locations, health outcomes, and pollutants should be studied; community involvement; choice of socioeconomic indicators; and policy concerns.
The conclusions presented here are intended to encourage collaborations to better understand and reduce disparities in environmental health.
# 2005 Elsevier Ltd. All rights reserved.
1. Introduction
While the relationship between socioeconomic conditions and air pollution as determinants of health has been
considered and studied for decades, at least as early as the
environmental justice movement, it is not fully understood. Collecting appropriate data, improving methods for
assessing socioeconomic status (SES), and encouraging
the application of uniform and sound methodology could
enhance the study of this topic. To help address these
* Corresponding author. Tel.: +1 203 432 9869; fax: +1 203 432 3817.
E-mail address: [email protected] (M.L. Bell).
1462-9011/$ – see front matter # 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.envsci.2005.06.003
research needs an international symposium was held to:
(1) discuss policy needs and motivations; (2) identify gaps
in currently available data; (3) share current research
results and theoretical approaches; and (4) identify future
directions for the study of socioeconomic conditions and
air pollution as determinants of health. The meeting was
held on September 23, 2003 in Perth, Australia, in
conjunction with the 15th Conference of the International
Society for Environmental Epidemiology (ISEE). The
symposium was attended by over 90 participants including
professors, public health officials, physicians, researchers,
economists, company managers, and doctoral students
from academic, government, research, and policy institu-
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M.L. Bell et al. / Environmental Science & Policy 8 (2005) 525–533
tions. Participants came from about 20 countries,
including Guatemala, Brazil, Singapore, Chile, the United
Kingdom, Australia, Taiwan, South Africa, Italy, Ghana,
and Germany.
The issues of air pollution exposure and socioeconomic
disadvantage are of special concern to rapidly developing
regions, which often have widespread poverty in conjunction with the high air pollution levels that typically
accompany industrial and economic growth. The proper
evaluation of the health effects associated with air pollution
and socioeconomic factors is of paramount importance in
establishing the real costs of development and lack of air
pollution control policies, and the distribution of those costs
among segments of society. Therefore, the attendance of
researchers from many countries of the developing world
was crucial for providing realistic suggestions on research
approaches, identifying challenges related to data collection
and quality, and describing policy-relevant topics.
The symposium builds on several previous initiatives.
The American Lung Association (ALA) held a workshop in
1999 to discuss air pollution and health inequities in U.S.
cities, with respect to the disparities between the air
pollution health consequences for the general population
versus those for urban populations with high proportions of
racial/ethnic minorities and people with lower incomes
(ALA, 2001). The Integrated Environmental Strategies
(IES) program and other sponsoring agencies held an
international meeting at the 2001 ISEE conference in which
participants recommended the development of hypotheses
on the modifying effect of SES on air pollution effects (Bell
et al., 2002a). A similar follow-up symposium was held in
Vancouver in conjunction with the 2002 ISEE conference
(Bell et al., 2002b). A related workshop on air pollution and
socioeconomic conditions was held at the Harvard School of
Public Health in 2002, and a review paper outlining
hypotheses, summarizing current knowledge and recommending next steps was developed afterward (O’Neill et al.,
2003). These workshops (Bell et al., 2002a,b; O’Neill et al.,
2003) identified the need for a meeting of international
experts on socioeconomic factors, air pollution, and health,
which led to the organization of the symposium discussed
here. The following describes the participants’ conclusions
and recommendations regarding future research efforts.
Additional information regarding the symposium, the
agenda, participant list, and detailed information on the
presentations is provided at http://www.airimpacts.org/isee/.
For the purposes of the workshop, the term socioeconomic
status was used in a broad sense, generally reflecting the
concept of a person’s relative position in a stratified society. A
rich tradition in sociology and philosophy is concerned with
societal stratification and its consequences. Detailed discussion of these traditions, as well as the variety of ways SES can
be measured, is found in Lynch and Kaplan (2000).
Discussions in the ISEE 2003 workshop were not aimed at
reaching a consensus on the definition of SES, but rather on
discussing issues and challenges related to the research and
the political, social and economic context in which such
research is conducted and results applied. Therefore, the term
SES in this paper should be understood to reflect that
researchers in attendance were interested in using data on both
personal characteristics (educational attainment, income,
race/ethnicity, occupation) as well as characteristics of
geographic places (housing features, neighborhood characteristics) to help them understand better the consequences of
environmental exposures in stratified societies.
Although the conference focused on SES, participants
highlighted the importance of also considering race and
ethnicity. Race and ethnicity are often highly correlated with
socioeconomic factors, such as educational opportunity or
income. Further, race and ethnicity can also affect environmental burdens. Racial minorities and lower income
populations may be exposed to higher air pollution levels
than white or richer populations (Apelberg et al., 2005;
Brown, 1995; Finkelstein et al., 2005; Sexton et al., 1993;
Thurston et al., 1992) and are more likely to reside near
hazardous facilities (Faber and Krieg, 2002; Morello-Frosch
et al., 2002). Both income and race appear to play a role in the
distribution of environmental health burdens, and the U.S.
Environmental Protection Agency’s definition of ‘‘environmental justice’’ considers race, ethnicity, and income
(USEPA, 2000, 2005). In addition, discrimination, displacement, and segregation are experienced differently by people
according to their race and ethnicity. The experience of the
Aboriginal peoples of Australia, the host country to the ISEE
conference, is an important example. Though we recognize
that SES is properly used as a concept distinct from race,
ethnicity, and/or immigrant status, information on both was of
interest to workshop participants, and is necessary for
improved research to understand and eliminate health
disparities (Ver Ploeg and Perrin, 2004). In a specific study,
it is important for researchers to carefully describe and
provide the rationale for their use of information on a person’s
race or ethnicity, education, neighborhood, or other data used
to categorize and compare individuals.
In the context of air pollution research, individual
socioeconomic indicators often represent underlying characteristics that affect susceptibility, exposure, or disease
diagnosis and treatment. Group-level information can reflect
characteristics of neighborhoods and groups of people that
can influence health and quality of life. SES, measured in
these ways, may influence the relationship between air
pollution and health through several pathways. Firstly,
persons in lower socioeconomic conditions have poorer
health in general, which could make them more susceptible to
the damaging effects of air pollution. Secondly, those in lower
socioeconomic circumstances may experience greater exposure to air pollutants, as they may live closer to roadways and
polluting industrial facilities and have larger occupational
exposure. Thirdly, they may have less access to health care
than other populations, creating an exacerbation of any health
response. This combination of increased susceptibility and
exposure suggests that SES indicators may be useful for
M.L. Bell et al. / Environmental Science & Policy 8 (2005) 525–533
characterizing populations that could face disproportionate
burdens from the environmental health danger of air pollution.
Several studies address relationships among socioeconomic factors, air pollution, and health (e.g., Gouveia and
Fletcher, 2000; Jerrett et al., 2004, 2005; Martins et al.,
2004; O’Neill et al., 2004; Perlin et al., 2001; Wojtyniak
et al., 2001). Research has shown differential exposure from
traffic-related air pollution with respect to SES (Gunier
et al., 2003), greater exposure to indoor air pollutants in
economically developing countries based on income (Smith
et al., 2000), and in some cases greater occupational
exposure to air pollutants for those in lower income brackets
(e.g., Rotko et al., 2000). In addition to exposure, baseline
health status and health-related behaviors differ by SES; for
example, smoking (CDC, 2005; Watson et al., 2003) and
physical activity (Giles-Corti and Donovan, 2002). A
discussion of hypotheses and research methods relevant to
the study of air pollution, SES and health, as well as a
summary of studies of socioeconomic factors and particulate
matter are given in O’Neill et al. (2003).
2. Challenges and recommendations
This workshop provided researchers and policy-makers
with an opportunity to explore how SES affects the
relationship between air pollution and health in terms of
research methods, data needs, policy considerations, and
future directions. Symposium participants were divided into
four working groups, each of which discussed separate
issues and presented their conclusions to the entire group.
Questions posed to the working groups included: what
geographical areas would be useful to study and why?
Which health outcomes are we interested in? Which are
most practical to study? Which have the biggest potential to
influence public policy? A full list of the questions is posted
online at the workshop website (http://www.airimpacts.org/
isee/). The following describes several key conclusions and
recommendations resulting from this symposium.
2.1. SES and research design
2.1.1. Place- and context-specific variation in the
meaning of SES
A crucial research issue is the choice and interpretation of
SES indicators. Local, regional, national, and international
variations in political and economic culture mean that SES
variables will have different meanings in various contexts.
Deciding what SES indicator should be used to identify
susceptible populations is as important a research consideration as determining exposure to air pollution, and bias
or measurement error. Common indicators of SES, such as
education, income, or income inequality, should be used for
multiple studies where feasible to aid comparisons, and in all
cases, the method by which SES was determined should be
clear.
527
Perceived SES may also differ by actual SES and by
region. In other words, people may actually be better or
worse off than they perceive themselves to be. For example,
in one study, working class adolescents were more likely
than upper middle class teens to misclassify their socioeconomic status (Goodman et al., 2000). Thus, an understanding of how SES itself affects self-perceptions of SES is
an important consideration.
2.1.2. Temporal aspects of SES
Participants discussed many variables used to classify
people in terms of SES (broadly defined), including poverty
levels, social networks, educational attainment, social
mobility, access to health services, insurance, housing
characteristics and location, crowding, occupation, income,
immigration status, and transportation use. These variables
are often highly correlated (Fukuda et al., 2004; Lahelma
et al., 2004). Some indicators define the current state (e.g.,
present-day income) and others provide historical information (e.g., income over the past 10 years). As in air pollution
research, cross-sectional or shorter-term data are generally
more widely available, but it is increasingly recognized that
SES over the lifecourse is an important determinant of health.
2.1.3. Correlation between SES indicators and other
variables
SES may be correlated to exposure to air pollution. For
instance, poorer persons may reside closer to roadways and/
or have higher occupational exposure. This is but one of the
potential connections between air pollution, SES, and
health. However, SES variables may also be connected with
other traits, such as age. The distinct contributions of these
factors to defining vulnerability may not be discernible, but
design and analysis methods can help address these
correlations. For example, different health effects by SES
could be studied only among elderly people so that age is
less likely to confound observed differences.
2.1.4. Identifying characteristics of interest
Because many indicators of SES are available, symposium participants recommended choosing suitable SES
indicators based on the potential policy action the research is
designed to inform. If a community has plans for an
intervention or legal action that pertains to particular
locations (e.g., diesel bus stops) or health-promoting
behaviors (e.g., access to parks or fresh fruits and
vegetables), using data that capture these characteristics
(e.g., proximity to bus stop, parks, or stores; income level, or
car ownership) would be important.
2.2. Health outcomes
2.2.1. A wide range of health outcomes
A variety of health effects could be considered for the
study of SES and air pollution, from more common, less
severe outcomes, such as respiratory symptoms to more rare
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and severe outcomes, such as death. Advantages of using
mortality for this type of research are that it can be defined
unambiguously, is of extreme health importance, and has
large economic and social costs, making it of interest to
policy-makers. Recent studies have found that those with
lower education are at the greatest risk of air pollutionrelated mortality (HEI, 2000; Hoek et al., 2002). Because
different pollutants may have varying effects on specific
causes, studies of cause-specific mortality can provide
insights into biological mechanisms, although all-cause
mortality will provide greater statistical power. As the
background rates of mortality and other diseases are elevated
in the lower SES groups, it may be more difficult to detect
the signal of air pollution effects. Other health outcomes
may be difficult to study in low SES populations because of
less access to and less seeking of health care, reporting bias,
and interpretation of questionnaires.
2004). Further, health responses in questionnaires may have
different meanings across regions. In the Central European
Study of Air Pollution and Respiratory Health (CESAR)
study, researchers noted different symptom prevalence
among the European countries, which could be the result
of actual prevalence differences, or the result of differences
in language and the interpretation of questionnaires. For
example, in Germany, there could be regional differences in
interpretation of terms like ‘‘wheeze.’’ Some subsets of the
population, such as immigrants, may be wary to report
health problems or participate in studies. The perception of
feeling ill also differs across social class, with people who
are less well off possibly having lower expectations of
health. Objective measures of health, such as pulmonary
function and cardiovascular outcomes, may be somewhat
better indicators of health status than subjective or selfreported measures.
2.2.2. Differential diagnosis and/or use of health care
services
Some subgroups of the population may be more likely to
use emergency rooms as health care rather than physicians’
clinics (Padgett and Brodsky, 1992). For example, immigrants are more likely to use emergency rooms than nativeborn residents in Copenhagen (Norredam et al., 2004), and
lower-income elderly African Americans were found to
have higher frequency of emergency room visits corresponding with lower access to physician services (Bazargan
et al., 1998). Hence, emergency room visits for respiratory
or cardiovascular disease may be appropriate outcomes for
these populations. In-depth community studies may be
necessary to identify health responses in cases where some
persons may not seek or have access to health care for
particular health endpoints.
2.3. Air pollutants and sources
2.2.3. Access to health data
The availability of health data may vary by SES. For
example, in Brazil, morbidity data are available from the
public health system, which attends to the poorest fraction of
society (Braga et al., 2001). The private medical care system
does not provide access to medical records at either the
individual or aggregate level. While mortality records
encompass information from the whole population, existing
morbidity data are limited, impairing effects estimates by
SES. Other regions may have missing or inaccurate
mortality data as well. In communities that face limited
health data, alternative sources of health information need to
be defined to allow a broad range of investigation.
2.2.4. Perception of health and health care
Perceptions of health can vary with SES, which should be
considered when using questionnaire data. In fact SES status
itself may have an impact on self-rated health (Nishi et al.,
2004), and the relationship between SES and self-perception
of health can vary by region (e.g., Jelsma and Ferguson,
2004; Reijneveld and Stronks, 2001; Szaflarski and Cubbins,
Numerous air pollutants have been associated with
adverse human health effects and many share similar sources
(Holgate et al., 1999). Thus, the choice of what pollutants to
study is not trivial. Participants discussed whether to
research individual pollutants (e.g., particulate matter,
ozone), pollution mixtures involving multiple contaminants
(e.g., sulfur dioxide and ozone together), or whole classes of
pollution sources (e.g., motor vehicle, stoves). This choice
will depend on the dominant sources and exposure pathways
for the study region, and what mitigation measures for
controlling sources and exposures are available to decisionmakers. For instance, environmental tobacco smoke and the
burning of biomass for cooking and heating are significant
sources of exposure, which may be related to SES. In India,
indoor air pollution from biomass as a cooking source is a
serious health threat, with associations between income
level and the types of fuel and cooking stoves (Mishra,
2003). A study in Guatemala identified an association
between the type of indoor fire and socioeconomic factors,
such as possession of a radio and television and floor type
(Bruce et al., 1998).
Exposure to traffic emissions is a major issue in most
countries, and a growing problem for rapidly developing
nations. The relationship between transportation-related
pollution and SES will differ by region, the nature of the
transportation fleet (e.g., diesel versus gasoline-fueled
engines), and the socioeconomic residential and working
patterns that affect proximity to roadways. In other cases,
industry will be the primary source of air pollution. Studies
could begin by focusing on the emissions sources that are the
major contributors to air pollution and/or those that are
poorly understood. These include the cement industry and
the petrochemical industry for some cities in Taiwan (Lin
et al., 2001; Yang et al., 2002, 2003); transportation,
electricity generation, industry, and home heating by wood
and coal in Australia and New Zealand (Kjellstrom et al.,
M.L. Bell et al. / Environmental Science & Policy 8 (2005) 525–533
2002); the burning of fossil fuel and increasing vehicular
emissions in Egypt (Anwar, 2003); and biomass burning in
Kenya (Ezzati and Kammen, 2001a,b).
529
population, which retains the same general population
characteristics with regard to SES and other factors, thus
controlling for some potential confounders, such as
smoking.
2.4. Geographic areas
2.5. Data needs
The choice of study region for research on socioeconomic
factors, air pollution, and health is critical as it determines
how the results can be interpreted and applied. Studies can
be conducted at the local, regional, or national scale, and the
choice of scale affects study design and the relevance to
policy. Because conditions such as baseline population
characteristics differ by region, results from one area may
not be readily applied to another location. Symposium
participants had several key recommendations regarding
choice of geographic area.
2.4.1. Leverage existing research
Basing study designs on areas for which other research
is already underway takes advantage of resources already
in place, such as datasets, knowledge of local communities, and a relationship with the local population and
government. Several examples of on-going relevant work
on air pollution that could integrate socioeconomic factors
are:
the IES program with studies in Beijing, Shanghai, Seoul,
Manila, Hyderabad, São Paulo, Buenos Aries, Santiago,
and Mexico City (www.nrel.gov/environment/environmental_strategies.html);
the meta-analysis of the Italian Studies on Short-term
Effects of Air Pollution (MISA) (Biggeri et al., 2001);
the Air Pollution and Health: a European American
Approach (APHENA) project, which builds on the Air
Pollution and Health: a European Approach (APHEA)
(Atkinson et al., 2001; Samoli et al., 2001, 2003; Sunyer
et al., 2003) and National Morbidity, Mortality, and Air
Pollution Study (NMMAPS) projects (HEI, 2003; Samet
et al., 2000a,b,c);
the Health Effects Institute (HEI) Public Health and Air
Pollution in Asia (PAPA) initiative (HEI, 2004).
Participants noted several data-related challenges. For
example, air pollution monitoring networks are typically
designed for regulatory compliance, and may not be ideally
located for health research or for evaluating SES factors.
Regions without extensive data should not be overlooked,
although there is a need for methodology to address datapoor areas, such as imputing missing data or using airport
visibility data to estimate pollution levels (e.g., Vajanapoom
et al., 2001).
2.6. Research needs
In addition to the data needs described above, research
needs include methods to compare results from different
locations; approaches to study areas with limited data on
SES, health outcome, and/or air pollution exposure; and
methods for data collection in various communities and
settings. A further research need is for statistical models to
help analyze the relationships between SES, air pollution,
and health. This issue is complex as the analysis of air
pollution health effects and SES must take into account nonlinearity, various lag structures, and confounders. The
multi-dimensional characteristics of this issue could be
addressed through hierarchical models that look at the
relationship in multiple levels, and through structural and
pathway models that account for a web of causation. The
symposium participants acknowledged the multi-disciplinary aspects of this topic and recommended collaborating
with social epidemiologists and health economists in
designing research on SES and air pollution. Case studies
were recommended as a way to explore research approaches
and to demonstrate the relationships between SES, air
pollution, and health.
2.7. Coordination and communication
2.4.2. Natural experiments
Studies encompassing changes in air pollution that take
place quickly, such as changes in transportation during the
1996 Olympic Games in Atlanta (Friedman et al., 2001) or a
ban on coal sales in Dublin (Clancy et al., 2002), can provide
insight into how SES affects the relationship between air
pollution and health. Future possibilities include the 2010
World Expo in Shanghai and the 2008 Olympics in Beijing,
which are likely to have significant changes in air pollution
concentrations. These occurrences offer unique opportunities to study public policy ‘‘interventions,’’ whether or not
intended for the purpose of health improvements. Additionally, since the studies compare health outcomes before
and after the event, the health impact is measured in the same
A key recommendation was enhanced communication
and coordination on several fronts. There should be better
synchronization among research efforts including the
addition of SES research to on-going investigations, which
can make use of existing research structures, databases,
and relationships with local communities. Further, there
should be increased involvement of the community, local,
regional, and national organizations at all stages, from
study design through to implementation and results’
dissemination. Strengthening ties between the community
and researchers can aid in multiple issues, such as
recruitment of study participants, researchers’ understanding of subjects’ perception of questionnaires, and
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M.L. Bell et al. / Environmental Science & Policy 8 (2005) 525–533
community trust in the study results. Also, involvement at
multiple organizational layers increases the probability of
successful response strategies, which may come from
different levels. Researchers should also coordinate with
decision-makers to determine whether their interest lies in
the health impacts of air pollution, SES, or both.
Consideration should be given to what types of information
are most useful to promote or support actions by policymakers and citizens. For example, some may respond more
to studies that include valuation and co-benefits. To
encourage this communication, symposium participants
recommended a follow-up workshop with researchers and
policy-makers. In particular, many thought that a useful
next step would include discussion of a series of in-depth
case studies where specific local problems were addressed
and research results affected policy.
2.8. Community involvement
A key feature of a successful study is involvement from
the local government and community, which is necessary to
ensure recruitment of study populations, researcher credibility, and an accurate understanding of local conditions,
such as health care systems and local income levels. This is
particularly important if the research is an intervention
study. The collection of data in lower SES may involve low
response rates due to community fears and language
barriers. Risk perceptions and health expectations may also
differ by SES.
Without local involvement, communities may perceive
that they are being used for research. These ‘‘overstudied’’
communities want solutions, not more research results. As
an example, local residents of the far over-drained and
extensively researched Aral Sea jokingly commented that if
every scientist brought a bucket of water, the sea would be
full by now (Hidalgo, 1999).
Community involvement in research can help address
residents’ concerns. Successful community participation
requires involvement at all stages: design, implementation,
and interpretation. Researchers should write about the
tangible advantages from collaborations with communities
and alternatives to the classic power relationship between
researcher and subject, in order to encourage community
participation by other research efforts. Such involvement
provides multiple benefits including cooperation of participants; access to indigenous knowledge; enhanced dissemination and understanding of results and related health
issues by the community; improved public perception of the
health research community; and heightened interest in and
application of results by local decision-makers. A strong
relationship between the researchers and community can
help illuminate the connections between risk factors and
health outcomes for both the researchers and local residents
(Smith, 1998). To succeed, community involvement should
be formalized (Steiner et al., 2005) and regularly assessed
(e.g., South et al., 2005).
2.9. Policy and decision-makers
2.9.1. Relationships to policy and other issues
This type of research delves into the social and political
structures that generate or perpetuate an SES gradient that
affects health, outside of the adverse impacts of air pollution.
Therefore, this work must be conducted with a broader
perspective of economics, society, and culture than would be
required by more traditional air pollution and health
research. These complex issues should not be examined
in isolation, especially as SES and air pollution can be
interconnected. For example, in China, the SES is generally
rising and more people can afford vehicles, which increases
emissions (Nehru et al., 1997). Increased access to
electricity may raise air pollution levels through emissions
from power plants, but also bring about changes in how food
is kept and prepared, leading to improvements in health.
Many air pollution control technologies, such as newer
automobiles and more technologically advanced indoor
cooking stoves, are expensive, creating additional connections between a community’s SES and exposure levels.
2.9.2. Interpretation of results
Studies of SES and air pollution are likely to be of
significant interest to policy-makers and the public.
However, the intended impact of the results may be
ambiguous. If disadvantaged populations are more affected
by air pollution, this raises the issue of how to address the
disproportionate impact and the origin of this burden. A key
issue for researchers is the degree to which these
components (air pollution, health, and SES) matter
separately to decision-makers and the public. For example,
a response to results identifying disproportionate impacts
from air pollution by income could be strategies to lower air
pollutant concentrations, policies to raise the SES of
populations, or both. Research results can be presented
and interpreted for decision-makers in a way that informs
development of interventions on both environmental and
socio-economic fronts.
2.9.3. Involvement of multiple agencies
The regulatory structures and governmental agencies that
address air pollution and poverty/development may be
separate. For example, in the U.S. issues of air pollution,
health, and socioeconomic concerns are addressed by
numerous organizations, such as the Environmental Protection Agency (USEPA), the Department of Health and
Human Services, the Centers for Disease Control and
Prevention, and the Department of Transportation. Thus,
addressing SES, air pollution, and health can involve
multiple agencies, such as those relating to transportation,
the environment, health, and energy. In order to get
meaningful decision-making and allocation of resources,
coordination between multiple organizations is required.
National, regional, and community-level organizations
should be included as they have different capacities for
M.L. Bell et al. / Environmental Science & Policy 8 (2005) 525–533
providing solutions. Whereas larger organizations can
enforce national policy, local agencies may be better
equipped for other solutions, such as public education and
change in the type of indoor cooking fuels.
3. Conclusions
In this international workshop, researchers and policymakers were provided with an opportunity to explore how
SES affects the relationship between air pollution and health
and make recommendations regarding research methods,
data, policy considerations, and communication. This
workshop was one of several recent activities that reflect
increased recognition of the importance of both social and
environmental determinants of health. The USEPA, for
example, published a Framework for Cumulative Risk
Assessment in 2003, which includes social stressors along
the spectrum of determinants of health that would be
important to consider in risk assessment (USEPA, 2003).
The USEPA subsequently invited the National Environmental Justice Advisory Council (NEJAC) to recommend
ways to implement concepts in the Framework to ensure
environmental justice (NEJAC, 2004). These efforts by
USEPA and NEJAC, previous workshops (ALA, 2001; Bell
et al., 2002a,b; O’Neill et al., 2003), and a growing number
of research studies highlight the rising concern regarding the
relationship between air pollution and health with respect to
SES.
By bringing together a group of international researchers
to discuss common research goals, challenges, and findings,
this workshop achieved the objectives of exchanging ideas
on research; making recommendations related to research,
interpretation, and policy; and providing new insights for the
participants on future directions and collaborations. International and interdisciplinary collaboration on social and
environmental determinants of health, as facilitated by
workshops such as this one, is critical to better understand
and to reduce the factors that unequally burden vulnerable
members of society.
Acknowledgements
We thank all participants of the symposium. This work
was sponsored by the U.S. Environmental Protection
Agency, the National Renewable Energy Laboratory, the
Health Effects Institute, the United Nations Environment
Programme (UNEP) Energy Programme Secretaria of
France, the U.S. Geological Survey, Australian National
University, the Clean Air Initiative Asia Secretariat, the
London School of Hygiene and Tropical Medicine, Monash
University in Australia, the World Bank, the World Health
Organization, the U.S. National Institute of Environmental
Health Sciences (grant T32 ES07069-24), and the International Society for Environmental Epidemiology.
531
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Michelle L. Bell is an assistant professor of environmental health at the Yale
School of Forestry and Environmental Studies, with a secondary appointment at the Yale School of Public Health. She holds degrees from the
Massachusetts Institute of Technology, Stanford University, and Johns
Hopkins University. Her research interests include air pollution and human
health, meteorological and air quality modeling, policy implications, and
the health consequences of climate change.
Marie S. O’Neill is a Robert Wood Johnson Health & Society Scholar at the
University of Michigan. She earned degrees from Brown University,
Harvard University and the University of North Carolina at Chapel Hill.
She has worked in the U.S. and Mexico in public health and environmental
organizations. Her research interests include health effects of air pollution
and temperature extremes, environmental exposure assessment, and socioeconomic disparities in environmental health.