A decline in the number of diesel cars would not jeopardise CO2 targets – in fact it would make them cheaper to achieve
The UK Society of Motor Manufacturers blamed February’s rise in the average new-car CO2 emissions on an “anti-diesel agenda [that] has set back progress on climate change”. Petrol v diesel cars is often presented as a trade-off between health-harming air pollution and climate-harmful CO2. Diesel cars do more miles to the litre than petrol, but this exaggerates the difference in CO2 emissions since one litre of diesel contains more energy and more carbon than one litre of petrol. If fuel were taxed on energy and carbon, rather than volume, then the tax on diesel would be 10 to 14% greaterthan that on petrol.
The International Council on Clean Transportation points out that petrol engines and petrol-hybrids have improved faster than diesel and will continue to do so. They conclude that a decline in diesel cars from around 56% to 15% would not jeopardise EU CO2 targets. Instead, it would make the targets cheaper to achievesince petrol engines cost less to make and have simpler exhaust clean-up. The future might be electric cars (or better yet for public health: cycling, walking and public transport), but in the short term new petrol cars, instead of diesel, might help both climate change and air pollution.
That London has got this far into the year before reaching these levels is a significant improvement on the past decade
Just a month into 2018 and London’s air pollution reached the legal limit for the entire year. While this is pretty dreadful, it's also a significant improvement over recent years.
In the past decade air pollution has reached illegal levels no more than a week into the year. Air toxicity has been at illegal levels in urban areas in the UK, including London, since 2010, resulting in around 40,000 early deaths a year.
The improvement can in part be attributed to Mayor Sadiq Khan’s actions to tackle the issue such as cleaner bus routes through the worst polluted areas and introducing charges to deter older, dirty vehicles into the city.
"This shows the measures we have already taken in the capital are beginning to take effect," he told The Guardian. "I am using all the powers I have to their fullest extent to tackle this health crisis. But it’s about time the government recognised the true scale of this issue."
But until radical changes are made the situation isn't drastically going to improve. Thankfully, there are some small changes you can make to help clean-up toxic air in London and reduce the amount inhaled.
Air Pollution: Current and Future Challenges
Source: EPA website