The London Congestion Charge Scheme may have had a "modest benefit" on levels of air pollution and life expectancy in the capital, finds research published ahead of print in Occupational and Environmental Medicine.
Extending it more widely and directly tackling vehicle emissions may see greater benefits for public health, say the authors.
AdvertisementThe Mayor of London introduced the vehicle levy in designated areas five years ago this month, in a bid to ease traffic in central London during working hours. The Congestion Charge Zone originally covered an area of 21 km2, and a resident population of 200,000 people. It was subsequently extended west to a much larger area last year.
The researchers focused on the original zone, and assessed the impacts of air pollution on health within the zone and across London as a whole.
They used models of annual levels of air pollution based on measurements of changes in traffic flow across London.
They focused on nitrogen dioxide (NO2) and particulate matter and the expected increase in life expectancy from reduced exposure to these pollutants.
The results showed that there was little change in pollutant levels in London as a whole. But there were more substantial falls in the charging zones.
Levels of NO2 fell the most. There were smaller falls in particulate matter levels, which the authors ascribe to the comparatively large amount that comes from outside the capital and the fact that sources other than vehicles contribute to this form of pollution.
But the changes in both pollutants were greatest in the most deprived areas of London.
The scheme has resulted in 1888 extra years of life gained across the overall population of Greater London (roughly 7.2 million people) and 683 years of life gained across the population in the congestion charging zone wards (approximately 370,000 people).
On a per population basis, the number of life years gained was therefore greater in the congestion charging zone, say the authors.
The Congestion Charge did not set out specifically to improve health, and it covered a comparatively small part of inner London, say the authors. But they conclude: "Policies affecting a larger geographical area and residential population, and which directly aim to reduce vehicle emissions, are likely to have larger public health impacts."
Traffic monitoring data published by Transport for London suggest that there has been a 26% fall in the number of cars and a 7% fall in heavy goods vehicles within the charging zones since the introduction of the Scheme.