Urban air pollution has emerged as a major health, economic and social threat, since cities expand at unprecedented rates across the world. In 1950, one-third of the world’s population lived in cities – today this has risen to one-half, and will reach two-thirds by 2050.
As urban air quality declines, the risk of respiratory diseases and other long-term health problems increases for local residents. Poor urban air quality is responsible for 3.7m deaths every year, 90% in low- and middle-income countries, according to the World Health Organisation (WHO). The economic costs of urban air pollution already stand at 2% of GDP in developed countries and 5% in developing countries. If no new policies are implemented, the OECD has forecast that urban air quality will continue to deteriorate, and could become the top cause of environmentally-related deaths worldwide by 2050, overtaking dirty water and poor sanitation.
This background briefing reviews the main challenges facing cities as they struggle to tackle air pollution. It aims to provide readers with information on the state of play of air pollution in industrialised and emerging economies, and gives examples of successful measures taken to combat air pollution at local level.