Feature

Pollution needs a good airing

Air quality should be accurate, understandable and more widely available, says Mary Stevens

Air is essential to life and good air quality is vital to good health. Current levels of air pollution are less drastic than the dense sulphurous smogs that haunted our cities before the Clean Air Acts of 1956 and 1968. The Department of the Environment (DoE) now monitors air pollution at sites around the country and issues air quality forecasts. Similarly, the Department of Health (DoH) issues warnings to vulnerable groups when safe levels of pollutants are exceeded, so everyone should be forewarned when air pollution is heading for unhealthy levels.

Why, then, is the majority of the population still ignorant of the extent of air pollution, and the nature and effects of air pollutants?

Over the weekend of 12 - 15 December 1991, cold, still weather conditions led to the worst winter smog in London since monitoring began in 1976. The DoH issued warnings and for the first time ever the DoE asked drivers in London to leave their cars at home. These warnings received minimal, and in some cases only retrospective, coverage from the media.

The DoE made air quality information available on a daily basis last year, after campaigning by environmental organisations and pressure from the media. But it appears most newspapers are interested in the news story drastic smog produces, rather than providing an information service for their readers. Raising public awareness of air pollution is an important step in combating it.

Currently only two national daily newspapers give regular air quality information, and vague references to ‘poor’ air quality are provided in some weather forecasts. In its present form, this information is likely to confuse rather than inform - most people do not know what ‘poor air quality’ means.

Here, then, is a summary of the most common air pollutants, their sources and effects:

Nitrogen oxides (NO, NO2): mainly from road vehicles and power stations, at high concentrations these cause throat and eye irritation.

Sulphur dioxide (SO2): from coal and oil burning; power stations and industry are the main sources. High concentrations cause eye, nose and throat irritation and lower levels may cause narrowing of the airways.

Ozone (O3): a summer pollutant formed by nitrogen oxides and hydrocarbons reacting in sunlight. The main sources are road vehicles and industry. A constituent of photochemical (summer) smog, low concentrations cause sore eyes, throat irritation, breathing difficulties and reduce the resistance of the lung to disease.

The effects of these pollutants on individuals depend on several factors, but the elderly, the very young and those taking vigorous exercise or suffering from respiratory problems are at greatest risk.

Asthma attacks may be triggered by common pollutants; the past decade has seen increases of 30 - 60 percent in deaths from asthma in countries including England and Wales, and the increasing number of ‘hay fever’ sufferers in cities has been linked to air pollutants. Exercise increases the amount of air drawn into the lungs, so joggers and cyclists are particularly vulnerable on congested city streets.

Although the level of air pollution experienced today is unlikely to produce effects on the scale of the 1952 pea-souper, which caused 4,000 deaths and precipitated the clean air acts, the episode last December should serve as a warning.

Pollution reduces our quality of life and our capacity to enjoy it. If we were better informed about the pollutants in the air we breathe, vulnerable groups could avoid discomfort and distress, and an educated public would hopefully recognise the lifestyle changes necessary to reduce pollution (e.g. lessening car use and energy consumption).

There is also confusion in the criteria used to assess air quality. The World Health Organisation (WHO) has established air quality guidelines and there are EC air quality standards for NO2 and SO2. The DoH simplifies pollutant levels into very good, good, poor and very poor (poor quality means adverse health effects may occur), and some local authority environmental health departments monitor their areas and use their own standards. But, for example, the DoH ‘good’ category for ozone and SO2 exceeds maximum levels set by WHO. So, even when information is published, there is still confusion as to its implications.

The current DoE monitoring network is limited and can only give regional indications of air quality but there are plans to expand it. The case for more widespread monitoring and better information was reinforced by a survey carried out by Edinburgh City Council between October 1990 and September 1991. Out of 14 sites monitored, 13 exceeded EC standards for NO2. This has prompted the council to encourage employees to use cycles by providing a bike pool and changing facilities. If more city authorities were to conduct similar surveys, they would probably get comparable results.

This winter cities around the world - Florence, Rome, Athens, London have all had cause to request reduction of, or ban, car use because of pollution. In Sao Paulo, Brazil, electronic pollution meters flash out air quality readings around the city - normally bad or very bad. The impact of the very high profile given to air quality information has created widespread public support for measures to reduce pollution.

WHO ozone guidelines were exceeded 252 times at 11 sites around the country in 1989 and 183 times in 1991, and throughout this winter air quality in the Midlands and Wales for NO2 and SO2 has frequently been poor. How many people are aware that their health is potentially at risk?

There is a need for more information and better public education on air quality. Currently, the reluctance of the British media to publish comprehensive and comprehensible daily pollution reports assures continuing ignorance.