Table 1.

Limitations of current green space work and work undertaken by PHENOTYPE to address these

Limitations of current available work	What PHENOTYPE will do
Inconsistency and variation in indicators for green or natural space have often made it difficult to compare results from different studies	Minimise the potential differences due to classification of natural space, by combining the use of conventional maps and data sources with remote sensing data and aerial photography, gather individual-level data through detailed discussions with participants living in the areas, and use considerable stakeholder engagement to develop comparable classifications of the natural environment in different countries Produce a more robust and comparable evidence base on links between exposure to natural outdoor environment and human health and well-being
A number of disease outcomes have been studied but, besides the routinely collected data (which use ICD coding), not always in a standardised and comparable manner in different countries	Produce a more robust and comparable evidence base on links between exposure to natural outdoor environment and human health and well-being, using well studied and new outcomes with standardisation between countries
Potentially very sensitive groups such as pregnant women/fetus have not been studied at all	Extend the evidence base to new outcomes and vulnerable populations, for example, pregnant women and their fetus, chronic respiratory and cardiovascular patients, ethnic minorities and low socioeconomic class
Most studies focused on green space; the evidence base for the effects of blue space is very limited	Not only examine the effects of green space, but also of blue space
Most of the green space studies have been conducted in the USA or the northwest of Europe	Conduct comparable studies across Europe and produce evidence for northwestern, eastern and southern Europe. This will deliver insights into regional, social and/or cultural differences in relation to natural space
Most studies do not include actual use of the natural environment	Consider actual use of the natural environment, an often neglected but fundamental indicator in relation to exposure to natural environments
There appeared to be differences in social group, with some apparently benefiting more than others from natural space, but the evidence is sparse	Produce a more robust and comparable evidence base on links between exposure to natural outdoor environment and human health and well-being, with special attention to effect modification by social groups
A number of potential mechanisms have been suggested, including increased physical activity and social contacts for those living near natural space, natural environments exerting stress lowering or attention restoring effects, and reducing environmental hazards (eg, air pollution, high temperatures). However, the studies of potential mechanisms have often been limited to assessing one mechanism at the time, which increases the likelihood of unmeasured confounding effects and misses the opportunity to study these potentially interrelated mechanisms in coherence. To study the mechanisms in coherence even though they may be interrelated	Examine the proposed mechanisms (physical activity, stress, social contacts, and environmental risk factors) simultaneously in a large sample in various countries (WP2). This will enable us to study specific factors while adjusting for others, and thereby strengthening the interpretation of the results
Unable to answer what specific quantitative and qualitative characteristics of the natural environment have a positive effect on health and well-being, and through what pathways is still largely unknown	Make classifications for the type and level of the indicators, which is important for policymakers Examine the importance of quantitative (amount, type, access, use) and qualitative characteristics (acoustic quality, identity, variety, safety) of the natural environment
Limited research exploring the sustained affective, cognitive and physiological responses to a single exposure and the effects of a repeated exposure to the same natural environment Unable to explain how policymakers and planners can design a natural environment to maximise health benefits	Explore longer term changes in affective, cognitive function and physiological indicators that have to date only been studied during, or immediately after engagement with the natural environment Explore the immediate, maintained and long-term effects of repeated engagement with the same natural environment on affective, cognitive function, and physiological indicators of well-being
Guidelines of lifestyle, health and well-being have largely undervalued local populations	Include lifestyle, health and well-being factors of the local populations

ICD, International Classification of Disease.