Toxic smog: hazard or hype?

Saturday 28 October, 16:0017:15, Frobisher Auditorium 1City life


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The issue of air pollution is rarely out of the news these days. Earlier this year, the ‘toxic smog’ that enveloped London was accompanied by claims that the city’s air pollution levels now surpass those in the ‘airmageddon’ of Beijing. Public officials urged children to remain inside schools at playtimes and warned older people to reduce their physical activity. Some reports suggest that nearly 40million people – more than half the UK population – now live in areas with illegal levels of air pollution. Worldwide, Bjørn Lomborg, self-styled ‘skeptical environmentalist’, says that the threat posed by global warming, estimated by the UN as 141,000 deaths per annum, is minor compared to the deadly threat of outdoor air pollution, which the UN says kills about 3.5million people each year. The Guardian’s John Vidal notes that pollution is now openly talked about as an ‘assault on a basic right to breathe clean air’.

Despite ominous reports, the issue of air pollution is complex and the extent of the deterioration and danger of air quality are disputed. An oft-cited report by the Committee on the Medical Effects of Air Pollution (COMEAP) estimates that annually in the UK there are 29,000 ‘attributable deaths’ from PM2.5 (particulates smaller than 2.5 micrometres). But Cambridge statistician Professor David Spiegelhalter shows the same data can be interpreted to mean a reduction in life expectancy of just three days. This doesn’t sound much, given that UK life expectancy at birth has increased by well over two years in the past decade.

Is concern about pollution today a legitimate interest in living longer, or is it simply morbid? After all, there has been considerable progress since the famous London smog of 1952, when particulate levels soared to many times higher even than today’s ‘emergency’ levels, which resulted in 12,000 deaths in just nine days. Is there legitimate concern that black smoke and air acidification from coal burning have been replaced by more dangerous pollution from microscopic particles and nitrogen dioxide (NO2), which Vidal argues is a ‘threat made more sinister by the fact it is largely invisible and unavoidable’.

While the extent of the threat is still debated, the clamour for action has grown. Some estate agents ensure property listings inform people of the air quality in their neighbourhood, while local authorities are considering ‘grey plaque’ health warnings on buildings in areas of high risk. Smart fabrics are being designed so that we can be alerted to incidents of high pollution. Elsewhere, the association between NO2 pollution and diesel vehicles, and anger over incidents such as the 2015 Volkswagen emissions scandal, have resulted in calls for new controls on car use, like introducing ‘ultra low emission zones’. But UK cities have also attracted criticism for failing to match the likes of Paris or Oslo, which are advancing plans to redesign their centres to exclude cars.

Do statistical models on pollution offer enough evidence to justify bans and redesigns? When the UN Environment Programme defines CO2 – a gas essential to almost all life on Earth – as pollution and the UK building regulations have policies on ‘noise pollution’ and ‘light pollution’, are we going overboard? Or is there a danger that rational policymaking is being overtaken by speculative fears?