Air pollution is a true invisible killer. We take the air around us for granted, but just as fish depend on clean water, clean air is obviously vital for our health and the health of our wider environment.
Back in the 1950s, smog was all too visible, and the deaths from it were front page news. The notorious Great Smog of London, even though it lasted just five days, is now believed to have killed as many as 12,000 people, and it led to the 1956 Clean Air Act.
While that legislation brought about significant improvements, mostly restricting the burning of coal in urban areas, the problem has not gone away. Government figures suggest that more than 2000 adults each year die in Scotland because of particulates in the atmosphere, particulates which are primarily a result of vehicle emissions.
It's a grim way of looking at it, but that same research estimates that more than 22,000 "life years" are lost as a result to adults alone. If something this lethal was more visible, it would surely be at the very top of our public health debate.
While the elderly are most at risk, children and young people are also seriously affected. The simple fact is that children in pushchairs are closer to the source of exhaust fumes. Similarly, people on lower incomes bear the brunt of this problem, as they are more likely to live nearer busy roads and further from green spaces.
Constituents of mine in western Edinburgh have raised concerns about this, especially around traffic lights, where air quality monitoring regularly shows pollution above the level which is seen as safe for children walking to school. It's a widespread problem across Scotland, with Friends of the Earth recently reporting that 38 areas breached safety limits last year, up from 33 the year before.
These figures should be enough to persuade the Government to act, but the ill health our polluted atmosphere causes costs us both personally and as a society. Treatment for avoidable illness and days off work make up the bulk of the financial costs, estimated at £20 billion across the UK.
The primary cause remains petrol and diesel engines, but in some areas, such as western Edinburgh, flights are part of the problem too. Flight numbers from Edinburgh airport last year were up by a million, which is great for their bottom line, but local residents (and the wider climate) are paying the price.
Airport expansion is too often seen in the narrowest terms: more bums on seats means more profits. These profits are made at our collective expense, though, both in terms of climate change and local air quality, and increased car journeys to and from our airports aggravate both problems too. Especially for domestic and short-haul flights, we need to see an end to runway expansion and more efficient and affordable rail network.
In 2015 the Scottish Government published a document sharing some of these concerns, but offering little practical action. More recently their focus has been on introducing Low Emission Zones for Aberdeen, Dundee, Edinburgh, and Glasgow by 2020. This would keep the most polluting vehicles off our most polluted streets, which is welcome, but do nothing to improve air quality in areas where the problem is less acute but still significant.
Instead we need a radical rethink of how we plan communities and how we travel. Most European cities have increased pedestrian areas, and their roads include kerbed-off cycle lanes and clear routes for public transport. Planning policy can put an end to the dependence on out-of-town shopping and start to support places where people can live and work without long commutes. Communities designed this way, for homes, work and play, bring all sorts of tangible and intangible benefits, including fresh clean air for us all.
Electric cars are no panacea: shifting away from petrol and diesel is worthwhile, but we also need to reduce the volume of traffic so our roads are safer for pedestrians and cyclists. In urban areas car-share services already work well for occasional drivers: government should be supporting access to services of this sort in our smaller towns too. Publicly-owned electric buses, running on renewable energy: these must be part of our future here too. Low emission zones must not just mean shifting dirtier old buses away to parts of the country that currently have better air quality.
This article first appeared in the National