The degradation of urban air has been principally caused by transportation systems, buildings and industry. Atmospheric pollutants such as particulate matter 2.5 (PM2.5) and nitrogen dioxide (NO2) represent a major risk to public health and are particularly harmful to children and the elderly. Studies undertaken by the WHO suggest that they could be the root cause of nearly a quarter of all adult deaths attributed to heart disease and stroke. They are furthermore responsible for nearly a third of all lung cancer deaths, and over 40% of terminal chronic obstructive pulmonary diseases. Children are likely to suffer grave health outcomes in later life, if exposed to these noxious substances. There are, of course, a range of fantastic environmental charities and research projects out there. Many among us will support these causes with our time and money. It is tempting to hope that, by doing so, we are equipping the experts with the tools they need to figure it all out. But as professionals working in the built environment, we are experts ourselves. The world looks to us for leadership; we each have a crucial, participatory role to play.
Cities are the world’s economic catalysts. They occupy 2% of the world’s land, consume 75% of its natural resources, produce 50% of global waste and contribute to 80% of greenhouse gas (GHG) emissions. Projections indicate that, by 2030, the world will be home to 43 megacities (>10 million inhabitants) most of which will be situated in developing regions. The United Nations predicts the urbanised population will grow from 55% of the global total in 2018, to 68% in 2050. At current rates of population growth, that means the world will, in just 30 years time, be home to an additional 2.5 billion city dwellers. Such demand can only be accommodated by the construction of around 230 billion additional square meters of urban living space. For context, that is roughly equivalent to building an area the size of Paris, with all its embodied carbon and resource requirement, every single week. As urbanisation continues apace, cities will require ever more energy to sustain their populations and support productivity. Failure to plan for growth in a carbon conscious manner will only lead to continued use of fossil fuels, increased GHG emissions, further air quality depletion and species loss. Too often the link between climate change and public health is missed. The people of the world’s cities are already suffering immeasurable damage as a result of this dual crisis.