Doctoral Dissertation Research: Segregation and Its Effects on Social Disparities in Exposure to Air Pollution

这一博士论文研究项目将通过考虑个人每天经历的各种空间(例如，家庭、工作场所和休闲活动地点)来研究种族和民族隔离如何影响空气污染的不平等暴露。博士生将开发一种个人层面的隔离措施，将这种更全面的隔离概念纳入其中，并将其与以高时空分辨率评估个人暴露于空气污染的方法相结合。这种新的细粒度方法将使研究人员能够更可靠地检查隔离和暴露在空气污染中的差异之间的联系，因为它可以改进之前研究中的几个方法学问题，这些问题完全是基于居住地的。超越单纯基于住宅隔离的简单化理解，研究结果将对环境暴露的差异如何通过复杂的社会空间过程形成以及非住宅隔离如何导致这些差异产生新的见解。调查人员将与相关组织和机构合作，传播项目调查结果。研究结果将通过强调考虑人类日常流动性的政策的必要性，为未来的政策建议提供更多细微差别的知识。调查结果还将有助于提高公众对空气污染造成的不公平负担以及解决这种差距的迫切需要的认识和理解。这个项目解决了三个具体的研究问题：1)个人在一天中是否经历了不同程度的隔离，如果是的话，少数族裔在白天(即在非住宅区)和晚上(即在住宅区)经历的隔离程度是否比多数人更高？2)不同种族群体的平均接触水平是否不同，如果是的话，哪个群体面临最高的空气污染暴露水平？3)观察到的一天中不同时间的隔离如何影响每天暴露在空气污染中的总差异？第一个问题将通过制定一种新的隔离措施来解决，该措施考虑到个人之间的时空接近程度，并结合活动-旅行日记数据集，其中包括个人特征和详细的每日旅行信息(例如，旅行的地理编码地点和持续时间)。将使用重复测量方差分析(ANOVA)来检验不同时间段之间的差异。为了回答第二个问题，博士生将使用地理信息系统(GIS)将暴露水平数据与日记数据以及通过空气扩散模拟产生的每小时空气污染数据整合在一起。然后将进行方差分析以比较种族差异。第三个问题的答案将是利用地理信息系统对不同时间的隔离和不同的空气污染暴露之间的空间关系进行地理可视化，并对这种关系进行回归分析。该项目将以佐治亚州大亚特兰大地区为基础，但将产生适用于美国许多其他大都市地区的信息。

This doctoral dissertation research project will examine how racial and ethnic segregation impacts the unequal exposure to air pollution by considering the full range of spaces individuals experience daily (e.g., home, workplace, and leisure activity locations). The doctoral student will develop an individual-level segregation measure that incorporates this more comprehensive conceptualization of segregation and combine it with a method for assessing personal exposure to air pollution at a high spatiotemporal resolution. This new fine-grained approach will enable investigators to more reliably examine the association between segregation and the disparity in exposure to air pollution because it can improve on several methodological problems in previous studies that were solely residence-based. Moving beyond simplistic understandings based solely on residential segregation, the research findings will yield new insights into how the disparities in environmental exposures are shaped through complex socio-spatial processes and how non-residential segregation contributes to those disparities. The investigators will collaborate with relevant organizations and agencies to disseminate the project findings. Findings will provide more nuanced knowledge for future policy recommendations by emphasizing the need for policies that consider human daily mobility. The findings will also help promote general awareness and understanding of the unfair burdens of air pollution and the urgent need to address such disparities. This new knowledge will contribute to a more inclusive and comprehensive participation in policy-making and engagement in a constructive dialogue about environmental justice and a wider range of social disparity issues stemming from segregation.This project addresses three specific research questions: 1) Do individuals experience different levels of segregation over the course of a day, and if so, do racial minorities experience higher levels of segregation both during the daytime (i.e., in non-residential areas) and at night (i.e., in residential areas) than the majority? 2) Are the average exposure levels of different racial groups different, and if so, which group faces the highest level of exposure to air pollution? 3) How does the observed segregation at different times of day affect the disparity in total daily exposure to air pollution? The first question will be addressed by developing a new segregation measure that considers spatiotemporal proximity among individuals in combination with an activity-travel diary dataset that includes personal characteristics and detailed daily travel information (e.g., geocoded locations and time durations of trips). The differences between time periods will be examined using a repeated-measures analysis of variance (ANOVA). To answer the second question the doctoral student will use a geographic information system (GIS) to integrate exposure level data with diary data, as well as hourly air pollution data produced from air dispersion modeling. An ANOVA will then be conducted to compare the racial differences. The third question will be answered by geo-visualizing the spatial relationship between segregation at different times and differential exposures to air pollution using GIS and by conducting regression analyses on the association. This project will be based in the greater Atlanta, Georgia, region, but will be generating information that will be applicable to many other metropolitan locations in the United States.