It’s the law of unintended consequences at work.
See...told you so.
European Union efforts to fight climate change favored diesel fuel over gasoline because it emits less carbon dioxide, or CO2. However, diesel’s contaminants have swamped benefits from measures that include a toll drivers pay to enter central London, a thriving bike-hire program and growing public-transport network.
“Successive governments knew more than 10 years ago that diesel was producing all these harmful pollutants, but they myopically plowed on with their CO2 agenda,” said Simon Birkett, founder of Clean Air in London, a nonprofit group. “It’s been a catastrophe for air pollution, and that’s not too strong a word. It’s a public-health catastrophe.”
How bad is it? Here's a comparison:
The EU limits NO2 to a maximum of 40 micrograms per cubic meter of air. The concentration on Marylebone Road, a stone’s throw from Regent’s Park, was almost 94 micrograms in 2012, according to the most recent data from the EEA.
The level for the site last year was 81 micrograms, and it’s averaging 83 micrograms this year, according to King’s College London. In 1998, when the King’s College data begins, it was 92. That’s about the time the switch to diesel started.
In contrast, Beijing had a concentration of 56 micrograms last year, according to China’s Ministry of Environmental Protection. The Chinese capital has a worse problem with other pollutants, registering almost triple the level of PM10 particles (bigger than PM2.5s) as on Marylebone Road.