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We wanted to know about nitrogen dioxide and air quality in Leeds, and we know that if you want to know what's really going on in Leeds, you need to go to the Town Hall, and ask a lion.
Folklore has it that when those four stone lions hear the Town Hall clock strike twelve, they awake, while the city freezes; and they make their rounds, seeing that all is well. They know.
The one to ask about air pollution is the one to the right, nearest the doors. He's been there since the peak of the industrial revolution, and peered at Leeds through thick, city-shutting smog into the mid-1950s; on and on into the clear, clean air we enjoy now. And he wears the scars. His proud head is corroded by the chemical-carrying air that enveloped him for so long, a visual reminder of the effects of air pollution.
The days when the city centre's air would be so dense with smoke, grit and danger that the streets had to be evacuated are now, mostly, a memory, but not entirely behind us. As recently as March 2015 clouds of air pollution triggered smog warnings in Yorkshire, raising concerns for anyone with respiratory problems and the elderly. For many people leaving the house was not an option; for others, they could only go around with inhalers to hand.
On most days, though, our air is clear. But does that mean it's clean? It's not only on days of discolouring smog that folk can have trouble breathing easily, and prescriptions for the treatment of asthma in Leeds cost £14,359,074m in 2014.
The threat now is from the chemicals we can't see. Nitrogen dioxide (NO2) is a major contributor to air pollution, and can cause increased likelihood of respiratory problems, reduced immunity to lung infections, and more frequent and intense attacks in asthma sufferers. The main source of NO2 is vehicle emissions, and although modern cars are manufactured to minimum standards and only produce small quantities of pollutants, large numbers of cars add up to a bigger problem.
NO2 levels are controlled by the European Union, and levels in Leeds city centre were above the EU's mandated limit last year, averaging 28.09parts per billion, compared to the target of 21ppb. That is much less than is found in the centre of London (47.47ppb), but more than you get walking down Piccadilly in Manchester (20.20ppb) or Fishergate in York (13.13ppb).
Not all of Leeds is affected the same way, though. Temple Newsam, for example, has an average of only 10.29ppb, positively easy-breathing compared to the city centre. Despite that, it also has some of the highest spend per person on asthma prescriptions in the city, £2,267, and a high rate of prevelance of asthma: 6.3% of the population. Car use in Temple Newsam is among the highest in the city, 37% of people making their daily commute by car. What impact are those commuters having on the local population; and how can asthma prevalence be reduced when the local NO2 levels are already low?
Commuters in the city centre are split much more evenly between drivers (16.7%) public transport users (13.2%) and, out in front, people who walk to work (23%). And yet people who limit their own emissions by walking to work in the city centre are still breathing some of the highest levels of NO2 in the city. So what else needs to change? Where do those high levels of air pollution come from?
The causes and effects of air pollution are tangled, interlinked and interdependent; Leeds is a city, after all, and in a city we all depend on each other. We made these short films to show the ways different lifestyles have different effects on our environment, and to show that the environment we affect is not always our own, but that of our neighbour. When it comes to the air we breathe, we're all in it together.
One fact stands out, though. On the day of the Grand Départ, when cars were banned from the centre of Leeds and cyclists took over, NO2 levels dropped by 20%. The lions, watching over the start line from the Town Hall steps, no doubt appreciated the difference. We can't host the Tour de France every day, though, so the question and the challenge is this: what else can we change in our lives to make another 20% change in the environment and the lives around us?
City centre living can offer the lifestyle benefits that come with a short commute, and many of Leeds' central residents take that advantage, 23% of them walking to work every day, the highest proportion of the areas we looked like. Another 13.2% use public transport, beaten only by Kirkstall's 17%, but more people use cars, at 16.7%.
Central Leeds is better known as a place of work than of living, though, and the density of commuters by car or bus must contribute to the city-highest average NO2 levels of 28.09ppb, in excess of the EU's limit of 21ppb. 74% of the NO2 measurements in 2014 were over 21ppb, compared to 37% in Headingley, 27% in Kirkstall, and just 8% in Temple Newsam.
Asthma prevalence is high, at 5.77% of the population, but prescription costs are low: £35,965, or £280 per 1,000 people, just 12.4% of the spend per person in Temple Newsam, where asthma prevalence is only marginally higher, at 6.3%.
Headingley residents have the lowest car usage of our four areas, and are evenly split along their ways to work; driving is the most popular, at 13.9%, closely followed by 12.6% who walk and another 12.6% who use public transport. Of those, 3% take the train, producing CO2 emissions of 3.45g/km, compared to 112g/km produced by an average driver in neighbouring Kirkstall.
Despite that, Headingley's average NO2 levels are only just below the EU limit of 21parts per billion, at 18.6ppb; it had the city's highest peak, with a recording of 246.7ppb, and 37% of recorded levels were above 21ppb. Asthma prevalence is the third highest of our four, at 5.4%, but spend on prescriptions is second highest, to a total of £122,794, or £984 per 1,000 people. Prevalence of strokes is also highest in Headingley, at 2.2%, as is heart disease, affecting 4.9% of people.
38.7% of commuters from Temple Newsam drive to work, the largest proportion in the areas we looked at; 12.1% use public transport, while only 4.9% walk to work. Another 4.9% do, however, are driven to work as passengers, the most significant car-sharing levels in these four areas.
CO2 emission levels from drivers are predictably high, at 129grams per kilometre, and asthma prevalence is the largest, affecting 6.3% of people in the area. The total annual cost of asthma prescriptions in Temple Newsam is £220,029; £2,267 per 1,000 people.
Despite that, average NO2 levels in Temple Newsam are the lowest of these four areas: just 10.29ppb, compared to 28.09ppb in the city centre, while life expectancy is also four-and-a-half years longer in Temple Newsam.
Kirkstall recorded the highest use of public transport of our four areas, at 17%; but only Temple Newsam had more car commuters, with 27.7% of Kirkstall residents driving to work, compared to 38.7% in Temple Newsam and just 13.9% in nearby Headingley.
Despite having twice as much car usage, Kirkstall has lower average NO2 levels than Headingley, 16.3parts per billion compared to 18.6ppb, and the lowest prevalence of asthma of our four areas, at 4.9%. Prevalence of strokes and heart disease are also lowest in Kirkstall, at 1% and 2.3%. Asthma prescriptions costs £380 for every 1,000 people, £100 more than in Headingley, but overall spend is lower: £100,410 compared to £122,794.
“WHEN IT COMES TO THE AIR WE BREATHE, WE'RE ALL IN IT TOGETHER. ”