Four years ago Sophie Power was walking along Marylebone Road, thinking of the son she was pregnant with at the time. The buses, lorries and cabs clogging the central London thoroughfare make it one of the most polluted places in the UK.
“I wondered how to protect him,” she says, pointing to a study that found children in polluted areas develop stunted lung capacity that is 8 to 10 per cent smaller as a result. “The pollution inevitably has an impact,” she says.
Although London’s air often appears clear to the naked eye, the city has suffered from illegal levels of air pollution since 2010, with particularly dangerous levels of nitrogen dioxide, which comes mainly from diesel vehicles. This summer’s unusually hot and sunny weather has caused surges in ozone — produced when sunlight reacts with nitrogen dioxide — that have prompted multiple pollution warnings.