On the Brink: All we need is the air we breathe

The average human being takes around 20,000 breaths each day. Simple arithmetic tells us that, by age 50, we will each have filled and emptied our lungs roughly 400 million times. For those of us living and working in cities, it is an uncomfortable reality that, more often than not, we are filling our chests with dangerously polluted air. In the modern metropolis, the simple act of walking to the supermarket, sitting in traffic, or taking the subway can seriously stress the respiratory system.

It is estimated that 95% of the global urbanised population is exposed to air pollution levels that exceed World Health Organization (WHO) recommendations. In other words, poor air quality is endemic in the world’s cities. It is also both a cause and side effect of climate change.

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.

In 30 years time, the world will be home to an additional 2.5 billion city dwellers. Such demand can only be accommodated by building a city the size of Paris every week.

Recent research published by C40 Cities has underlined the scale of both the challenge and the opportunity. Their analysis of 25 cities showed that cleaner, greener transport networks, greater use of renewables to power buildings and decarbonisation of energy grids would result in huge environmental gains. PM2.5 levels could be brought down by 49%, while GHG emissions could be reduced by as much as 87%. The health benefits of any such improvements in air quality would be massive: up to 223,000 premature deaths could be averted each year in C40 cities alone. Actions undertaken to reduce emissions will enhance urban air quality and, by extension health outcomes for the most vulnerable among us. Clearly establishing that link between the climate emergency and our personal health and wellbeing will be a crucial factor in driving meaningful behavioural and policy change.

Climate change is undeniably a human made emergency. We have dragged our planet to the brink of disaster. GHGs and other emissions are poisoning the air we breathe. Biodiversity loss and ecosystem obliteration is compromising the agricultural supply chain and spoiling the food we eat. I have no doubt that built environment professionals understand the link between air quality degradation and planetary warming. Our challenge is to communicate this link, and then practice what we preach in the ways we work.

The adverse effects of climate change are already manifest – not least in the increasingly lethal properties of the air we breathe. We must remember that the present is simply time borrowed from our children’s future. We each have guiding hand in designing that future; the world we leave behind must be better than that which we inherited. This is a call to action, and I extend it to each and every one of our readers.