Mechanism Assessment

Workpackage 2 – Mechanism Assessment
Led by Hanneke Kruize, RIVM

Potential mechanisms of the health benefits in relationship to exposure to the natural (green) outdoor environment have been investigated. Included are physical activity, stress reduction, restoration, social contacts, and reduction of exposure to environmental hazards. These have not been measured simultaneously and the studies have mostly been conducted in northwest Europe and the USA. Inconsistency and variation in indicators for green or natural space have often made it difficult to compare results from different studies.

WP2 explores the mechanisms underlying the relationship between the natural environment and health & well-being for different population groups. The focus will be on different levels of urbanity and rurality, and include both ‘green’ and ‘blue’ areas. One thousand volunteers are recruited in Lithuania, the Netherlands, Spain and UK, to provide detailed information on the natural environment and mechanisms/determinants of health impacts related to the natural environment.

New data is being collected collected on:

Characteristics of the natural environment; Frequency and way people use the environment; Indicators of the potential mechanisms; Self-reported health & well-being; Socio-demographic variables.

Conventional land use maps, remote sensing data and aerial photography are used, and discussions held with volunteers and stakeholders to produce comparable classifications of the natural environment.

Qualitative and quantitative data will be collected to characterise the natural environment. Different spatial scales will be examined such as city/town, neighbourhood or street level. Comparable indices will be produces in the different countries to be able to analyse the results. New technology called ‘Calfit’ is used to collect information on the mechanism in question. Calfit is a cell-phone body sensor that runs on a Google Android 2.2 operating system that can collect data on physical activity with accelerometry, geographic location though a global positioning system (GPS), air pollution likely to arise from automobile traffic, and interactive text messages capable of eliciting ecological momentary assessment (EMA).

Through random or fixed interval texting to the volunteer, Calfit can monitor his/her emotional state, the local environment and the social setting, to contextualize the exposure journey through time and space. The EMA uses a real-time data capture strategy to assess self-reported behaviour, mood, social and physical contexts as antecedents, concomitants, and consequences of environmental exposures. EMA is a novel approach to elicit responses to electronic surveys throughout the course of daily life. EMA has advantages over retrospective self-report measures for investigating time-varying processes by: Reducing the delay between the experience of the volunteer and the assessment period. This reduces memory errors and biases of the person involved. EMA collects multiple observations over the course of a day, which permits the investigation of daily and within-daily variability. Electronic entries are time-stamped and therefore allow for valid comparisons of temporal relationships.

EMA reduces human error introduced through data management because data are sent via SMS to a secure computer database, eliminating the need for manual data entry.

WP3 will liaise closely with policymakers, land use planners, health professionals and green space managers and other stakeholders to obtain results that can be used in WP5 (Implications, Policy and Guidelines) to develop implementation guidelines for policymakers, and others involved with design and management of the natural environment.