Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - MobiliSense (Air pollution and noise exposure related to personal transport behaviour: short-term and longer-term effects on health)

Teaser

- Building on methods from Epidemiology, Geography, and Transport sciences, the objectives of MobiliSense are to quantify the contribution of personal transport to the air pollution and noise exposure of individuals; to compare the air pollution and noise exposure in the...

Summary

- Building on methods from Epidemiology, Geography, and Transport sciences, the objectives of MobiliSense are to quantify the contribution of personal transport to the air pollution and noise exposure of individuals; to compare the air pollution and noise exposure in the different transport modes; to investigate whether total and transport-related personal exposure to air pollutants and noise are associated with short-term and two-year changes in respiratory and cardiovascular health; and to examine whether transport-related exposures mediate socioeconomic disparities in health.
- The MobiliSense project is strongly related to ongoing policy efforts both at the national and European levels (i) in the field of Transport, (ii) for the regulation of air pollution, and (iii) for the regulation of noise. Overall, in the context of the insufficient evidence available attributable to the limitations of scientific studies, it is important to develop innovative research strategies to derive more reliable data on transport-related environmental exposures and on their health effects, to support international, European, and national policy efforts. The main and critical limitation of previous literature on this topic is that studies have evaluated the influence of air pollutants and noise separately; previous studies may therefore be heavily biased.
- The MobiliSense project will explore the short-term and longer-term effects that air pollution and noise exposures related to personal transport behaviour may have on respiratory health and cardiovascular health. Its final aim is to converge towards the development of a flexible simulation tool for decision-makers to orientate policies to mitigate the detrimental health effects of transport-related exposures.

Work performed

This first period of 30 months was entirely devoted to the preparation of the MobiliSense data collection, which is extremely complex. MobiliSense involves the recruitment of 1000 participants, monitored with complex tools, and seen again for a second evaluation after two years.
Briefly, we were able to take the following actions:
- We conceived the sampling frame of the MobiliSense cohort (sample size, several participants allowed per household, survey of new household when target household has moved, Grand Paris as the study territory, definition of the geographic strata for sampling, definition of clusters of neighbourhoods within strata, inclusion and exclusion criteria, definition of individual-level strata of hypertensives, respiratory disease participants, and public transport users, decision to measure blood pressure during the recruitment and to perform a spirometry test only for participants with at least one positive answer to 7 questions, calculation of the probability of selection in each individual stratum, protocol for taking non-response into account).
- We developed and performed an extensive testing of the different questionnaires (eligibility questionnaire, acceptation questionnaire, sensor equipment and measurements questionnaire, biological sample questionnaire, main questionnaire, VERITAS mobility questionnaire, post-questionnaire, Trip Builder Web mobility questionnaire, and smartphone-based questionnaires). We closely followed the electronic implementation and debugging of these questionnaires with the dedicated companies. All these applications are now fully ready to start the data collection.
- We conceived additional applications for the management of the process of recruitment of participants: a Participant manager, an Activity manager, and a Device manager. We closely followed the development of these applications, which are now fully ready, with the dedicated companies.
- We validated the final list of sensors to use in the data collection, and prepared the measurement protocols for these sensors (decisions on the configurations after testing). We bought and parameterised these numerous devices. We also bought the numerous other furniture needed for this project.
- We conceived the organisation of the data collection period (definition of how to establish the contact with participants, of the sequence of operations on the recruitment day, of how to take the biological samples and how to store them, of the sensors to carry on each day, of the different forms and instruction sheets given to the participants, of which text messages are sent to the participants on each day to support the data collection, of the exposure and health reports sent to the participants after the study, etc.).
- We obtained all the legal allowances for conducting this project and we were able to obtain the official label from the National Statistical Information Committee, meaning that our MobiliSense study is now part of French Statistics system, which is extremely rare for an epidemiologic study.
- We thus obtained the right to sample our participants from the French Population Census, and have performed the sampling with the French National Institute of Statistical Studies. We performed the double entry of information from 33501 census sheets in a scanned format.
- We prepared all the operational and management procedures for the recruitment of participants (assignment of participants to research assistants, preparation of the guidebook of instructions for the research assistants and of instruction sheets for the participants, management of working days and day-off, etc.).
- We hired survey technicians and trained them to the many complex technologies to be used during the data collection.
- We performed a pilot study recruiting real participants from the Grand Paris study territory in order to train the survey technicians and test the study procedures. This pilot study appears to be successful.

Final results

- To contribute to strengthen the partnership at the local, national, and European levels between Public health and Urban planning decision-makers and inform European and national policies designed to mitigate the environmental hazards associated with motorised transport, our project aims to provide a more comprehensive evaluation of the health effects of exposures related to personal transport behaviour than previous studies, by building on innovative data collection and analytic methods from Epidemiology and Social epidemiology, Geography, and Transport sciences.
- Regarding measurement strategies, a key strength of the project is that it systematically relies on objective measurement approaches for the assessment of exposures, confounders, and health outcomes. The protocol uses passive sensors of location, behaviour, environmental conditions, and health (GPS receivers, accelerometers, air pollution and noise sensors, heart rate monitors, and ambulatory blood pressure monitors) and active sensors, i.e., devices requiring an action of the subject for measurement (blood pressure at rest and spirometry). The use of some of these sensors / monitors is extremely innovative: the recently developed ambulatory blood pressure monitor that will be used (TensioMed Arteriograph) measures central blood pressure (which is more predictive of target organ damage than brachial blood pressure) and aortic pulse wave velocity and the augmentation index as markers of arterial stiffness; the BioPatch will allow us to assess heart rate variability but also accelerometry and the respiratory rate; and no study has ever relied on a repeated smartphone survey to assess respiratory symptoms as close as possible from their onset.
A second measurement strength of the project, integrating methodologies from Public health / Nutrition and Transport sciences, is related to the precise measurement of personal transport behaviour over 6 days using GPS receivers and a GPS data-based electronic survey of activities and transport modes. This approach allows us to decompose in a precise way the 6-day follow-up period into time spent at the different activity places and trips and trip stages (segments of trips with a unique mode), permitting to ascribe the data collected with the behavioural, environmental, and health sensors to each trip or activity place time segment of the mobility survey.
- Moreover, based on a systematic survey assessment of how people regularly go to their visited places, we will develop a methodology to distinguish between casual transport behaviour over 6 days and regular transport behaviour (over a longer period), as needed to investigate short-term and longer-term effects of transport on health.
- Other measurement strengths of the project include, as very few studies have done, the simultaneous monitoring of air pollution and noise with personal monitors, and the comparison of exposure measures based on personal sensors and GPS tracks (Geographic methodology).
- As important information for the development of European and national policies, these ground-breaking innovations will permit, compared to previous research, (i) to precisely quantify the percentage of exposure to various air pollutants and noise that is attributable to the transport activity; (ii) to establish a more precise link between the use of each transport mode and the exposure to air pollutants and noise as a way to better understand source-specific impacts as recently recommended; and (iii) to assess the health impacts of scenarios of changes both in personal transport behaviour and in exposure levels during transport.
- The latter simulations will test scenarios of interventions changing in a probabilistic way the transport behaviour of individuals (number, length, destination, and transport modes of trips) and / or the level of environmental exposure during trips. Our perspective is to package this methodology to perform flexible simulations of scenarios in a tool