Evidence of the strongest links between environmental factors, health inequalities and impacts on health is summarised in the table below.

This is based on the findings of the The Marmot Review: Implications for Spatial Planning.

Environmental factor Health inequalities impact Health impacts
Air pollution Poorer communities have a higher prevalence of cardio-respiratory and other diseases Strong evidence that reductions in traffic to reduce air pollution are successful in improving health
Green/open space 35 per cent of people in the lowest social grade visit green spaces infrequently (less that once a month), which is likely to be due to low availability and poor quality of green space in deprived areas. Strong evidence that provision of green space effectively improves mental health.
Less strong/inconclusive evidence that provision of green space improves levels of physical activity.
Transport and traffic* Children are four times more likely to be hit by a car in the 10 per cent most deprived wards than in the least deprived wards Strong evidence that traffic interventions reduce road accidents.
Some inconclusive evidence that traffic interventions improve physical activity.
Food Low income and area deprivation are both barriers to purchasing fresh or unfamiliar foods Anecdotal evidence that local access to healthy foods improves diets
Housing Children in bad housing are more likely to have mental health problems, such as anxiety and depression, and a range of other ill health effects ? cold housing can affect the numbers of winter deaths and respiratory diseases Some evidence that targeting home improvements at low-income households significantly improves social functioning as well as physical and emotional wellbeing
Community participation and social isolation In many communities facing multiple deprivation, stress, isolation and depression are all very common, and low levels of social integration and loneliness significantly increase mortality Some evidence that increasing community empowerment may result in communities acting to change their social, material and political environments

* Note that the review finds that the links between transport and health are ?multiple and complex? ? as well as the negative health impact set out above, transport (of some form) provides access to work, education, social networks and services, which can also have a positive health impact.
Source: Plugging health into planning (Local Government Group, 2011)

The evidence base for the links between the wider determinants of health, health promotion interventions targeting these, and health outcomes continues to improve ? updates from organisations such as Public Health England and NICE should be kept under review. However, waiting until a perfect dataset is produced is not a sensible option.