EC air quality standards begin to take shape

Recommendations for four new EC air quality standards, currently being considered by the European Commission, could spell significant changes to the UK's air quality strategy. The Commission is expected to propose a relatively tough standard for nitrogen dioxide - but its proposal on sulphur dioxide is likely to be considerably less stringent than the UK's standard.

The EC framework Directive on air quality, formally adopted last September, was a major step forward in harmonising Member States' approaches towards managing air pollution.

Although the Directive adopts a similar approach to the UK's air quality strategy, several significant differences are contained in the detail. The Confederation of British Industry and the Chemical Industries Association have complained that their members will be placed at a competitive disadvantage because the UK's air quality objectives must be met by 2005 while most of the forthcoming EC standards will not have to be met until 2010 (ENDS Report 262, pp 33-34 ).

The impact of the EC standards in the UK will depend to a great extent on the approach adopted by the new Labour Government. In opposition, Labour pledged a thorough review of the UK's air quality strategy and complained that several of its standards and objectives were too weak (ENDS Report 266, pp 33-34 ). However, the new Ministers have yet to say whether they intend to modify the existing strategy and the draft regulations which will underpin it.

The Commission is to propose daughter Directives setting air quality standards and monitoring requirements for 12 pollutants. Interim values are likely to be set for several pollutants. Member States will be required to identify areas of poor, improving and good air quality, and take action to ensure compliance with the interim values and, by the specified deadlines, with the limit values.

The Commission has confirmed that the World Health Organization's recent recommendations for air quality guidelines in Europe will form the basis of its proposals. It is now considering the recommendations of its working groups for the first four standards, with a view to publishing proposed "daughter" Directives in the summer.

An interim cost-benefit study is understood to have concluded that the health and environmental benefits of the proposed standards for NO2, SO2 and particulates would far outweigh the costs. The opposite applies to the proposed standard for lead.

Working groups on carbon monoxide, benzene and ozone have recently been set up, and the Commission hopes to issue proposals for these in early 1998. Standards for polyaromatic hydrocarbons and various metals are unlikely to be proposed before the end of 1999.

The groups' deliberations have been shrouded in confidentiality. However, ENDS understands that they have made the following recommendations:

  • Fine particulates: Growing evidence linking particulates with a diameter of less than ten microns (PM10) with adverse health effects has made them a priority for regulators.

    The Commission's working group, chaired by Germany and the UK, has proposed a 24-hour limit value of 50µg/m3. This figure is identical to the UK standard. However, the WHO declined to put forward a standard on the grounds that it was unable to identify a safe level of exposure.

    The UK's provisional objective is to secure 99th percentile compliance by 2005, but the working group has proposed a less demanding 98th percentile compliance by 2010. Its main concern is that high natural levels of dust in southern Member States could make the standard hard to meet - indeed, derogations for some southern areas are likely.

    The working group's proposal differs from the UK strategy in two further respects. Firstly, an annual mean level of 20µg/m3 is proposed which could prove difficult to meet in major cities or coal-burning areas.

    Secondly, the group has recommended that the smaller PM2.5 fraction should also be measured with a view to replacing the PM10 standard with one for PM2.5 at the first revision. Increasingly, epidemiological studies have shown that PM2.5 has a stronger association with ill health than PM10. However, pressure to move towards PM2.5 has so far been resisted by the UK's Department of the Environment - and could mean added work and expenditure for local authorities.

  • Nitrogen dioxide: Last December, the UK's Expert Panel on Air Quality Standards (EPAQS) caused controversy by proposing an hourly average standard for NO2 of 150ppb (286µg/m3) - considerably weaker than the new WHO standard of 200µg/m3 (ENDS Report 263, pp 8-9 ). The Government accepted the recommendation.

    However, the NO2 working group has endorsed the WHO figure which, it says, should be achieved at the 99.9th percentile by 2010. If the proposal is accepted by the Commission and Member States, the UK would have to move to the tighter standard.

    A tougher hourly standard may, however, not cause too much trouble for the UK. Firstly, the EC standard would have to be met by 2010 - five years after the deadline in the UK strategy. Secondly, the UK strategy retained a backstop in the form of an annual NO2 limit of 21ppb (40µg/m3) - identical to that proposed by the working group.

    Finally, the working group also proposed an annual standard of 30µg/m3 to protect sensitive ecosystems. This would not apply in built-up areas.

  • Sulphur dioxide: The working group has put forward an hourly limit value of 350µg/m3, with 24 permitted exceedences per year. Unlike proposals for other pollutants, the standard would apply in 2005 and not 2010. A "margin of tolerance" of 150µg/m3 would effectively set a standard of 500µg/m3 for the first five years after the Directive takes effect.

    The proposal is apparently based on an extrapolation of the WHO's new guideline of 500µg/m3, which applies as a 10-minute average. Although medical evidence has linked short-term peak concentrations of SO2 to adverse health effects, the group felt it impractical to set a standard based on an averaging period of less than one hour.

    The group's conclusions have important implications for the UK, where EPAQS' standard of 100ppb (262µg/m3) as a 15-minute average has been accepted. The UK standard - which has been widely criticised by industry - is considerably more demanding than the working group's proposal. Under the terms of the framework Directive, the UK could choose to retain a national standard tougher than that set at EC level.

    The working group also proposed a daily limit value for SO2 of 125µg/m3 and an annual mean value of 20µg/m3 to protect ecosystems. A tougher annual limit of 10-15µg/m3 would apply in zones with monuments sensitive to SO2 damage.

  • Lead: The WHO, the UK and the Commission's working group have all proposed an annual mean limit of 0.5µg/m3. The working group has also recommended a limit value for lead deposition, which is believed to contribute more to exposure than lead in air.

    Industry bodies have lobbied hard to retain the old WHO standard of 2µg/m3, arguing that the new standard will be difficult to meet near smelters and other industrial plant.

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