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Exhausted arguments

The alleged links between air pollution, ill health and cars are largely hot air, suggests transport consultant Keith McCabe

Launching the government's new set of air quality targets in January, deputy prime minister John Prescott announced that New Labour is 'determined to deal with air pollution, to deliver on our commitment to clean air'. But what is it that needs to be dealt with to deliver clean air in the new millennium?

In the detail of its 'Air quality review', the government conceded that its targets for reducing particulate matter (PM10) and ozone would not be met by the deadline of 2005. The main cause of this problem, it argued, was no longer car exhaust fumes in Britain itself, but imported pollution from continental Europe.

The Green Party was outraged. 'Blaming Europe for our air pollution is nothing short of a total cop out', said its spokesman. 'It is obvious that road traffic pollution is fundamental to improving the serious problem of air pollution.' It may be 'obvious' to the environmentalist lobby, but is it true?

For the Greens the issue is clear-cut. 'Air pollution has serious health problems, causing cancer, asthma and many other dreadful diseases and ailments. Road traffic is responsible for the majority of pollution.' Friends of the Earth supports this view. 'Traffic pollution is a big issue. There are over 21 million cars in the UK releasing a cocktail of health-threatening pollutants.'

Yet recent evidence casts serious doubt on the assumed link between air pollution, ill health and cars.

According to the government's own experts, no link has been established between air pollution and asthma. A Department of Health report, 'Asthma and outdoor air pollution', states that: 'There is some laboratory evidence that exposure to the common gaseous pollutants can enhance the response of asthmatic patients to allergens, though the effect does not seem to be large. There is no direct evidence for such an interaction as a result of exposure to outdoor air pollution in the UK.'

Nor are non-asthmatics considered particularly at risk from air pollution. As one of the supporting documents to the 'Air quality review' explains: 'Healthy individuals are not thought to be at significant risk from current levels of air pollution in the UK, but studies have indicated associations which persist at relatively low levels, between daily variations in the levels of some pollutants and the daily variations in mortality and hospital admissions for acute respiratory conditions.'

In other words, if you are a healthy person you have little to fear from air pollution. If you have a severe respiratory complaint, the report suggests, air pollution may cause you to be admitted to hospital, or in some cases to die anything from a few days to a year prematurely. But even this is open to question. The research on premature deaths was based on a statistical association between high air pollution and increases in death rates. Since high pollution in winter occurs mainly on very cold days and in summer on hot muggy days, weather factors, as well as air pollution, could increase the levels of premature deaths. Current estimates are that the annual rate of premature deaths in Britain should fall by about 2000 to approximately 18 000 by the year 2010.

To put these figures into perspective, it is worth contrasting them to a time when air pollution really was a problem. In London one pollution incident in December 1952 resulted in at least 3000 deaths more than expected for that time of year. More than 80 percent of these were individuals with known heart and respiratory disease. This incident, combined with ones in 1948 and 1956, led to the introduction of the Clean Air Act and the setting up of smokeless zones.

The introduction to the 'Air quality review' makes the point that 'such extreme pollution is a thing of the past'. Overall, air pollution is getting better rather than worse. A recent report showed that on average urban areas have 40 days of poor air quality a year and the trend is downwards. Rural areas, however, also have 40 days of poor air quality a year and the trend is static. This means that air quality is good on average for 325 days a year, whether you live in a city or a village.

Not only is the problem of air pollution widely exaggerated today, but the scientific evidence also suggests that cars cannot be held to blame for it. Improvements in technology mean that the problems of the 1980s are disappearing. Lead and carbon monoxide - the traditional problems caused by traffic - are no longer a serious problem. The problem of nitrogen dioxide may be with us for another couple of years, but is likely to be limited to the traffic-heavy London roads.

The main air quality problems of the twenty-first century in Britain seem set to be particulate matter (PM10 and PM2.5) and ozone. This is why the government's air quality strategy no longer assumes that the car is primarily to blame for poor air quality, and why imported pollution from Europe has been targeted as the main sources of PM and ozone. The much-hyped problem of air pollution from cars, one of the principal arguments against private car use, is not the all-encompassing problem that it is cracked up to be, and nowhere near the problem that it was even five years ago.

Bert Morris of the Automobile Association argues that private motorists are being unfairly burdened by additional 'anti-pollution' taxes. 'Since 1992', he points out, 'catalytic converters have been fitted to all new cars, leading to a 32 percent reduction in toxic pollution. Yet the 500 000 buses and trucks on the road today emit more particulates - the pollutant of most concern to air quality managers - than the UK's 23 million cars'.

The Green Party and Friends of the Earth may be preaching to the catalytically converted when they attack the motor car for causing air pollution and damaging the nation's health - but they are also well wide of the mark. The problem of air pollution is reducing and the government can meet its 12.5 percent target for the reduction in greenhouse gas emissions without the introduction of drastic anti-car measures. Unlike Henry Ford's day, cars are not as black as they are painted.

Keith McCabe is a consultant for WS Atkins Planning and Management Consultants Ltd

Reproduced from LM issue 119, April 1999

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