Accounting for mobility in air pollution exposure estimates in studies on long-term health effects

This study aims to improve our understanding of the contribution of individual mobility in air pollution exposure estimates. The investigators will use location tracking on a mobile phone application for 2,000 individuals in the Netherlands and Switzerland.

Poster abstract for HEI Annual Conference 2023

MOBI-AIR: Accounting for MOBility in AIR pollution exposure estimates in studies on long-term health effects

Kees de Hoogh^1,2, Nicole Probst-Hensch^1,2, Medea Imboden^1,2, Danielle Vienneau^1,2, Ayoung Jeoung^1,2 Benjamin Flückiger^1.2 Gerard Hoek³, Roel Vermeulen³, Kalliopi Kyriakou³, Derek Karssenberg⁴, Oliver Schmitz⁴

¹Swiss Tropical and Public Health Institute; Allschwil, Switzerland

²Basel University; Basel, Switzerland

³Institute for Risk Assessment Sciences (IRAS), Utrecht University; Utrecht, the Netherlands

⁴Department of Physical Geography (Geo), Utrecht University; Utrecht, the Netherlands

Background. Large scale epidemiological studies investigating long-term health effects of air pollution can typically only consider the residential locations of the participants, thereby ignoring the space-time activity patterns that likely influence total exposure. People are mobile and can be exposed to considerably different levels of air pollution or air pollution mixtures when inside vs. outside, commuting, recreating, or working. Neglecting these mechanisms in exposure assessment may lead to incorrect distributions of exposure over the population, which may lead to incorrect exposure health relations in epidemiological studies. The main aim of this study is to assess whether more sophisticated estimates of individual exposure, considering population mobility, decreases the bias in health studies.

Methods. An agent-based modelling framework combining space-time mapping of pollution and activity-based mobility simulation has been developed and applied to address locations of individuals of the SAPALDIA cohort and the Swiss National Cohort (SNC) in Switzerland and the EPIC cohort in the Ntherlands to facilitate further epidemiological analysis. To test how well the agent-based model simulate tracks, we are conducting tracking campaigns in Switzerland and the Netherlands where participants are asked to fill in a time activity diary using a purpose-designed app and carry a GPS sensor for 2 weeks.   

Results. In Basel we sent out invitation emails in September 2022 to 731 COVCO-Basel (recent COVID research cohort) participants who reported their willingness to participate in environmental research. 304 of 731 people responded (response rate ~42%) and of those, 210 completed the tracking campaign. A second wave of 732 invitation emails was sent out in January 2023. In the Netherlands, invitation letters were sent out in September 2022 to 3000 randomly selected addresses across the Netherlands. We received only 41 positive responses (response rate 1.4%), prompting new recruitment strategies through social media. In total 78 subjects (41 from the letters and 37 via social media) registered and of those, 43 completed the tracking campaign. We aim to continue with the tracking campaigns in both Basel and the Netherlands until April 2023. This will give us ample time to recruit and track as many participants as possible and enough time to analyse the data and use it as a validation dataset for the ABM modelling.

Conclusions. Next step is to link the track data to long-term average hourly air pollution surfaces by weekday and weekend day and to compare residential exposures with agent-based modelling derived exposures.