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  3. PhD Candidate - Measuring the General External Exposome 2: Addressing the Modifiable Spatiotemporal Unit Problem

PhD Candidate - Measuring the General External Exposome 2: Addressing the Modifiable Spatiotemporal Unit Problem

Utrecht University's Faculty of Geosciences is looking for a PhD Candidate. Are you interested? Then please read the full profile and apply.

11 dagen geleden


Domplein, Utrecht, Utrecht
Tijdelijk contract / Tijdelijke opdracht
Uren per week:
36 - 40 uur
€ 2325 - € 2325 per maand


The physical and social environments we live in have significant impacts on our health. They contribute to about 70% of the world’s chronic disease burden. Since many aspects of our environment are modifiable, this provides a huge potential for disease prevention. Leading scientists in Europe and the USA have formalized this perspective as the Exposome concept. The Exposome comprises aspects of the built environment, the social environment, the physicochemical environment, and people’s lifestyle.

To study the Exposome, we need to examine both the multitude of interrelated individual exposures, the wider behavioral and social context in which these exposures occur, and their impact inside the human body. The external Exposome encompasses the context in which humans spend time, move through, and in which behaviors take place and, eventually, which impacts human health. Uncovering individuals’ Exposome will thus require capturing the dynamics of environmental exposures at the individual level along people’s daily movement over long periods of time. This will require a combination of several advanced geospatial technologies, such as GPS tracking, mobile sensors, and geospatial big data. Through deploying advanced geospatial methods and data, this part of the Exposome NL project focuses on measuring the general external Exposome by developing and validating methods not only for obtaining detailed data about environmental factors like pollutants and psychosocial stressors but also for assessing their health impacts while addressing significant methodological issues. Since contextual variables are derived on different spatial and temporal units as well as different scales, aggregation and discretization schemes may be different, research results may differ when different units of analysis are used.

Job description
This part of the Exposome NL project aims to develop analytical frameworks and methods to address the modifiable spatiotemporal unit problem. The research tasks include:
  1. To study how different spatial and temporal frameworks would influence research results on the external Exposome, and how do the modifiable areal and temporal unit problem might interact to complicate any attempt to mitigate the modifiable spatiotemporal unit problem. We will develop a high-dimensional analytical framework for high-resolution space-time analysis by extending 2D GIS to 3D and 4D. We will then integrate environmental data over space-time using various temporal scales, segmentation schemes, and temporal boundaries as well as over multiple spatial scales for studying the external Exposome. We will also assess the effectiveness of the methods developed using different geodata sources. We will examine how much bias the modifiable spatiotemporal unit problem may introduce into estimates of statistical parameters and measures of association when one moves from one spatial/temporal scale to another.
  2. To develop analytical frameworks and methods to address the modifiable spatiotemporal unit problem, including developing high-dimensional analytical frameworks that can flexibly integrate large amount of environmental data over multiple spatial and temporal scales for studying the external Exposome, with high space-time resolution that enables fine-scaled space-time analysis. We will also assess the effectiveness of these frameworks and methods using a GPS dataset collected from participants in the panel study.
  3. Another important task is to help the main group to develop data collection instruments and survey questions and help to link this part of the Exposome NL project to other parts of the project.


We are looking for a passionate candidate with a strong motivation to pursue a PhD-degree, who:

  • has a degree in health science, geographic information science, geography, or related disciplines by the time of appointment;
  • has proven interest in and enthusiasm about the outlined research topics and methods;
  • is well versed in quantitative data analytics (e.g., in R) and geographic information systems;
  • has good knowledge in conducting a survey and is familiar collecting GPS data;
  • is proficient in both spoken and written English and have excellent communication skills.


We offer a temporary position (1.0 FTE), initially for one year with extension to four years in total upon a successful assessment in the first year, and with the specific intent that it results in a doctorate within this period. The gross salary ranges between €2,325 and €2,972 (scale P according to the Collective Labour Agreement Dutch Universities) per month for a full-time employment.
Salaries are supplemented with a holiday bonus of 8% and a year-end bonus of 8.3% per year. In addition, Utrecht University offers excellent secondary conditions, including an attractive retirement scheme, (partly paid) parental leave and flexible employment conditions (multiple choice model). More information about working at Utrecht University can be found here.

Additional information

For more information about this position, please contact: Dr Marco Helbich (Associate Professor), via m.helbich@uu.nl


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