Shockingly, 2017 is the third year in a row that London had breached the annual air pollution limit within seven days, and this year, it only took five days for it to happen. On Thursday night, an air-quality monitoring station on Brixton Road in south London breached the limit 19 times, reaching 347.7 ug/m3 at 9 p.m.
European Union rules demand that maximum hourly concentrations of nitrogen dioxide - which can cause severe health problems - mostly caused by road traffic in towns and cities, are not exceeded for more than 18 hours a year.
But by January 5, readings on a road in the city had passed those limits.
"The mix of these toxic air pollution levels with freezing temperatures poses a serious risk to people with lung conditions and can affect all of our health".
Londoners might want to consider wearing an air filter mask, with news that the city's annual air pollution has been met in the first five days of 2017.
Last month Paris made public transport temporarily free in an attempt to tackle high levels of pollution.
Six city-wide "clean air zones" - in which owners of large diesel vehicles would be hit with charges to deter them from driving in - were already in line to be in force by 2020 in Birmingham, Leeds, Southampton, Nottingham and Derby, and by 2025 in London. And while London's mayor is trying to improve the city' air quality, the United Kingdom government's national plans to tackle pollution have been ruled to be illegal, and sent back to the drawing board for the past two years.
To make these ambitious initiatives a reality the Mayor has allocated more than £875million to help tackle this invisible killer - more than double the funding allocated by his predecessor. He also announced a £50 million programme to give buses priority over other traffic, reducing so-called idling, where they keep their engines running while stopped because of lights or congestion.
Environmental campaigners called for tough action to clean up Britain's air - including phasing out the sale of diesel vehicles.
"The government needs to match the mayor's commitment to improving air quality as quickly as possible".
Friends of the Earth is among those calling for urgent action to tackle air pollution which it says causes nearly 10,000 premature deaths in the capital every year.
Cleaner buses and taxis have an important role to play and change to the perverse taxes that encourage people to buy diesel over cleaner cars is needed.