Pollutant levels drop in central London 17 years after carbon tax introduction

Marylebone, Bloomsbury and Westminster had lower levels of carbon monoxide, nitrogen dioxide and sulphur dioxide in 2020, compared to 2003, a study found

By Shagun
Published: Friday 10 January 2020

Carbon monoxide (CO) levels fell 62 per cent, nitrogen dioxide (NO2) 24 per cent and sulphur dioxide (SO2) 60 per cent, on an average, in at least three areas in London where congestion charges were introduced 17 years ago, a recent study claimed. 

Congestion charges are collected from motor vehicle drivers on entering demarcated zones in central London between 7 am and 6 pm, Mondays-Fridays.

CO reduced significantly soon after the congestion charge was brought in 2003 and kept falling at the three sites — Marylebone, Bloomsbury, and Westminster — according to the study by vehicle-leasing company Select Car Leasing.

Levels of SO2 — produced by combustion engines when sulphur reacts in the atmosphere to form fine particles and other pollutants — fell 62 per cent in Marylebone, 75 per cent in Bloombsury and 25 per cent in Westminster. 

The reduction in NO, however, was less dramatic. In Marylebone, in fact, it rose in the years immediately after the introuction of the charges, but then fell 25 per cent. In Bloomsbury too, the levels first rose and then fell from 2006. By 2019, there was a 25 per cent reduction from 2003 levels. Westminster recored a 30 per cent fall. 

The study was aimed at gauging the impact of the congestion charge on the city’s air quality in the three sites. The levels of emissions today were compared with before the introduction of the concept in London in February 2003.

Due to the success of the London congestion zone, 20 other cities are either planning or have confirmed they will be implementing low emission or clean air zones in the near future. 

“The purpose of these zones is to target diesel cars and older, more polluting petrol-powered vehicles. The trend of increasing toll roads, low emission zones and congestion charges shows no sign of slowing down as the move towards conserving the environment grows stronger and more urgent,” said a press release by Select Car Leasing. 

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