In our opinion environmental pollution should be

In our opinion, environmental pollution should be considered as a common risk factor for both dementia and schizophrenia. Studies are warranted to test this hypothesis, and if confirmed, the clinical implications could be of great importance for public and mental health. Future research, including large population-based studies, is likely to focus on investigation of the effects of specific components of environmental pollution on increased risk for mental, neurodevelopmental, and neurodegenerative diseases in human beings, with the aim to plan possible prevention strategies. Policy measures, regulatory interventions, and aggressive air quality management programmes are needed to reduce current air pollution levels and the associated burden of disease, so bringing substantial health benefits across a broad spectrum of disease.
One of the key lessons that can be learnt from the history of public health is that many major public health advances—from clean drinking water to tobacco control—have been led at the local level. As we enter the Anthropocene, and strive to embrace an ecosocial approach that can address the implications for population health of the global ecological changes humans are creating, once again much of the leadership and action will need to occur at the local level. This position does not deny the need for global-level action to address boundary-spanning issues such as climate change, ozone depletion, or persistent organic pollutants (three examples for which international agreements have recently been made). Unfortunately, such global-level action is usually time-consuming and fraught with difficulties. Meanwhile, local governments have often shown more commitment and been quicker to act. Earth\'s human population is now mostly urban, with almost 55% of people living in cities, a proportion expected to grow to 66% by 2050. Cities produce about 80% of global gross domestic product, and are responsible for more than 75% of natural resource consumption, 60–80% of citco consumption, and 75% of global carbon emissions. It can, therefore, be argued that the battle for planetary health will be won or lost in the world\'s cities. One way to understand the scale of human impact on the Earth is the ecological footprint (EF). Globally, the EF exceeded the Earth\'s biocapacity (put simply, the Earth\'s capacity to produce resources and ecological services) in about 1970, and as of 2012 had grown to 1·6 times that figure, even though in that period biocapacity itself grew slightly due to increased agricultural productivity. Moreover, high-income countries (HICs) required 6·2 global hectares per person in 2012, which was 3·6 times the available biocapacity of 1·7 global hectares per person. In other words, people living in HICs require, on average, 3–4 planet\'s worth of biocapacity to sustain present ways of living. Because this situation is unsustainable, we must learn to live on the one small planet that is our home, but in a way that also ensures a good quality of life, and a long and healthy life, for all. This predicament has led to the concept of so-called One Planet living, in which all individuals, communities, and nations have to abide by inherent resource constraints. The challenge is particularly hard for people living in HICs because of the need to reduce their ecological footprint by up to 75%. However, HICs have a responsibility and ethical duty to do just this for several reasons: they have become the model to which many people in many other countries aspire, and they take far more than their fair share of the Earth\'s resources and have done so for many decades, if not centuries. The transformation in societies, economies, and ways of life to achieve One Planet living represents a key 21st century population health challenge. International movements are already based on local approaches to these issues, such as Healthy Cities, Sustainable Cities, and the Transition Network, but effective co-ordination between and integration of health and sustainable development is frequently not prioritised. Because of One Planet living\'s concern to address both life quality and wellbeing and the EF, it offers an integrative approach with the potential to release synergies at local and regional levels. Bioregional, a UK-based charity and social enterprise working around the world with developers and municipal governments, among others, created its One Planet Living initiative in 2003. Its ten One Planet Principles () begin with health and happiness and also address other social concerns (eg, culture and community, equity and local economy) in addition to environmental and urban planning focus areas.