Dust, pollen, soot and smoke particles contaminate London’s air.
Small particles enter Londoners’ lungs and damage their health. Nitrogen dioxide and ozone are two of London’s main pollutants. These modern pollutants are very different to London’s earlier pollutant – the sulphur dioxide gas caused by burned coal.
Particulate matter comes in coarse fractions from PM 2.5 up to PM10 and includes earth, grit and other ‘fugitive dust’ from the city’s roads and industry. Smaller fine and ultra-fine particles consist of acids, gases and aerosols. They vary aerodynamically so travel differently. They also position themselves within the lungs differently too.
London’s 21st century pollutants represent an invisible threat. For instance, a human hair is 60 micro-metres in diameter. Six PM10 particles can be lined up across one hair or 24 PM2.5 particles. Millions and even billions of such particles can come out of a diesel vehicle’s exhaust every minute. These much smaller particles reach farther inside our bodies.
The Department of Health’s Committee on the Medical Effects of Air Pollutants (COMEAP) reported in 2010 that long-term daily exposure to particulates leads to the equivalent of 29,000 premature deaths or an average loss of at least six months of life for everyone. Of course, those are mathematical calculations. Some people lose a few days whilst others lose years, depending on genetics, exposure levels and where and how people live. Yet COMEAP reported that air pollution could reasonably be linked to the premature cardiovascular deaths of up to 2,000 people in 2008, with an average loss of life of about two years for each afflicted person.
Death caused by pollution sits at the top of a much larger pyramid. Pollution contributes to respiratory, heart and blood vessel conditions. Pollution also results in more visits to doctors and hospitals and increased use of medication. Everyone is afflicted to some extent.
Traffic is the main source of pollution in cities.
In London, it is primarily diesel traffic. For example, diesel buses and taxis fill Oxford Street and the Euston Road. Diesels emit slightly less carbon dioxide than petrol engines but emit more particles and nitrogen dioxide. A controlled experiment in northern Sweden – where the air is pure – involved volunteers exercising on bikes in a chamber whilst exposed to diesel emission levels found on Oxford Street. A bronchoscopy revealed black carbon in the lungs.
Cells patrol the lungs and remove these foreign materials so they can be swallowed and excreted. But cells die when they take in too much diesel and so the body is less protected against further pollution and other viruses. Similar experiments show black carbon present in lung fluid coughed up by school children in east London. Such experiments show traffic pollution worsens school children’s breathing and allergies and lessens their quality of life.
Pollution-related illnesses present Londoners with a political choice. London’s Low Emission Zone (LEZ), established in February 2008, aims to progressively reduce traffic-related air pollution – and so improve the city’s air quality and the health of Londoners. Vehicles must meet emissions standards, or pay a daily charge. The LEZ affects larger diesel vehicles, such as vans, trucks and coaches but not cars and taxis. They must meet EU emission standards to enter the zone, or pay a penalty fine. The LEZ has progressively affected more vehicles and imposed stricter emissions limits.
But some studies have concluded that the LEZ has had no beneficial impact, including for schoolchildren struggling with respiratory and allergic symptoms.
Other ways to eradicate pollution exist. For instance, the New West End Company pedestrianises Oxford Street and Regent Street once a year. Black carbon levels disappear on those no-vehicle days.
Cleaner fuels could be developed and used. The congestion zone could be extended and the charge increased. Diesel vehicles could be phased out and replaced with more hybrid hydrogen and electric buses and taxis.
Other cities offer potential solutions. Public transport in Paris is made free on selected days to reduce car usage. Lyon and Perth are piloting the use of driverless autonomous electric buses.
Can driverless autonomous electric cars also be part of 21st Century London?
© Paul Coleman, London Intelligence, December 2016