Cities are crucial to public health. They are sources of cultural, technological and economic innovation, but they can also be breeding grounds for injustice, disease, environmental destruction, and violence.
By 2030, they will be home to seven of every 10 humans on the planet. Through history, urbanization has changed our understanding of public health, and today, there is an emerging paradigm based on human life in cities. We now know that health and well-being are not only a matter of access to medical services, but are determined by the social conditions—dictated by political, social-cultural and economic forces—in which people live, work and age. Building a healthy city therefore requires access to good-quality housing, public transportation, education, work, recreation, and cultural facilities. Social protection and a healthy environment are equally important. Finally, equity—or, the fair distribution of these assets—is crucial to overall urban health.
Urban social injustice is epitomized by shantytowns and squatter settlements. Today, these are home to approximately 1 billion people, and that number may double in the coming decades. But shantytowns are also motors of urbanization. In their constant search for opportunities, residents generate a variety of new enterprises—economic, cultural, educational, and social—as well as strong social support networks.
The urban environment affects human health in three principal ways. The first is related to the social and behavioral impact on individuals—their eating habits, levels of physical activity, sexual practices, safety, and drug use. The urban poor have limited access to information and services, an abundant supply of high-caloric and processed foods, and living conditions that don’t favor healthy behaviors. This results in higher rates of diseases such as obesity, hypertension, heart attacks, diabetes, and cancer. Migrants’ loss of connection to their original cultures affects mental health, which is connected, along with corruption, police brutality and inequality, to high rates of urban violence—the primary cause of death among persons aged 15 to 45 in Brazilian cities. Likewise, vulnerability to AIDS among urban residents is associated with poverty, gender inequality and access to education.
The second is related to the physical urban environment itself. Poor living conditions favor disease transmission and increase the risk of contact with contaminated air, water, food, and soil. Respiratory disease caused by air pollution kills thousands of people each year in cities such as São Paulo and Mexico City (and 130,000 worldwide). The planet’s 800 million cars pollute the atmosphere and kill approximately 750,000 people every year due to accidents.
Climate change is the third factor. Three-quarters of global greenhouse gas emissions come from urban centers in developed countries. Yet it is these cities’ residents, especially the poor, who will suffer the most from the likely effects of global warming: heat waves, insufficient supplies of water and food, changes in infectious disease patterns, and rising sea levels.
Questions of injustice and inequality are intimately related to both the quality of the urban environment and health. In São Paulo, the wealthiest sections of the city have 176 times more green space than poorer sections. Poorer neighborhoods also have 1,000 times fewer libraries and report teenage pregnancy and mortality rates that are nine and 14 times greater than in wealthier ones.
Such inequalities are increasingly considered unacceptable, and an emerging movement is aiming to achieve greater urban health and justice. The movement is powered by social participation and the concept of healthy governance: integrated urban planning initiatives in public health, environment, education, transportation, economic activity, education, and culture based on partnerships between governments, the community and the private sector.
Several programs in Latin America have pointed the way. In Brazil, the Programa de Saúde da Família (Family Health Program) reaches 100 million people, the majority in poor areas. It is working with urban residents in at-risk areas on issues such as degradation of green spaces and public spaces, waste disposal and recycling, sanitation, and home hygiene and ventilation. Grassroots groups such as the Rede de Comunidades Saudáveis (Healthy Communities Network) in Rio de Janeiro have helped empower citizens by promoting dialogue between communities and the government. In São Paulo and in 20 other cities that make up the Rede Brasileira de Cidades Justas e Sustentáveis (Brazilian Network of Fair and Sustainable Cities), citizens and nongovernmental organizations are demanding transparent and egalitarian governance based on verifiable goals. Urban planners are beginning to rethink the design and planning of cities, and are favoring walkways and bicycle paths. New initiatives in the favelas are beginning to invest more in participation and in social actions.
In Colombia, citizenship and governance programs have radically changed the face of cities such as Bogotá and Medellín over the last 10 years, resulting in an improved quality of life.
For this movement to expand, we need new leaders who are open to a style of governance that is both participatory and fair. Governance that places health, sustainability and quality of life at the center of its actions can go a long way toward correcting inequalities and building cities that are more just and environmentally healthy.