Air quality standards proposed for next phase of LAQM

The Government has proposed a raft of new air quality standards to drive the local air quality management (LAQM) regime forward over the next decade. It has sparked controversy by putting forward a less stringent objective for particle pollution in London than elsewhere in England, while Scotland also intends to go further than England - the first time such variations have been proposed for any UK environmental quality standard.1

The UK air quality strategy, introduced in January 2000, set objectives for eight pollutants to be achieved between the end of 2003 and 2008 (ENDS Report 300, pp 37-38 ). The LAQM regime requires local authorities to take action to control emissions if these objectives are likely to be breached.

In September, nine months later than promised, the Government published proposals for updating the strategy. It has put forward new objectives for three pollutants - particles, benzene and carbon monoxide - and proposed an objective for polycyclic aromatic hydrocarbons (PAHs) for the first time (see table).

The objective for carbon monoxide will directly replace the existing objective for 2003. Other existing objectives will stand, but will be complemented by new targets to be achieved by 2010. The move effectively heralds a second phase for the LAQM regime in the second half of the decade.

  • Particles: The objectives for fine particles (PM10) have been amended with bewildering frequency.

    Last year's strategy came under fire for weakening the air quality objective for PM10. It set a 24-hour mean of 50µg/m3 with 35 permitted exceedences per year as an "interim" target, along with an annual mean of 40µg/m3. Both objectives were to be achieved by the end of 2004.

    Meanwhile, concern about the health impact of particles has continued to grow. In 1998, the Department of Health's Committee on the Medical Effects of Air Pollutants (COMEAP) estimated that short-term particle pollution episodes kill around 8,000 people every year in England and Wales. This year, the Committee warned that long-term exposure could be up to ten times more significant (ENDS Report 316, p 15 ).

    COMEAP now estimates that for every 1µg/m3 reduction in average annual particle levels, life expectancy across the UK population would be increased by around 0.2-0.5 million life-years, or 1.5 to 3.5 days per person. Moreover, these figures are towards the low end of possible scenarios and could be as much as an order of magnitude higher.

    The Government has used this advice to justify a significantly tighter objective to be met by 2010. For England and Wales, the 24-hour mean of 50µg/m3 could be exceeded just seven times a year, while the annual mean would be halved to 20µg/m3.

    However, a more ambitious annual mean of 18µg/m3 will apply in Scotland. The Welsh Assembly is also considering adopting a tighter objective.

    In contrast, the Government has sparked controversy by proposing a weaker set of objectives for London. In the capital, the proposed annual mean objective is 23-25µg/m3 - and 10-14 annual exceedences of the 24-hour mean objective would be permitted.

    Richard Mills of the National Society for Clean Air slammed the proposals to treat London differently. "Targets should be set in order to drive action, not adjusted for problematic areas so that they can be met with existing measures," he said. "Are the residents of Hounslow and Hillingdon to expect a lower standard of protection than those in neighbouring Surrey and Berkshire?"

    Mr Meacher defended the proposals. "I'm not keen on two-tier systems, but if we had the same standard for London it would be letting the rest of the country off," he said. "Air pollution levels in London are such that a target that is challenging for London would be pretty straightforward for the rest of the country? and one that is challenging for the rest of the country would frankly be impossible for London."

    He also pointed to proposals for a long-term annual mean of 20µg/m3 for London to be met by 2015. "We're not letting London off," he insisted. "This is a very, very demanding set of measures."

    Annual mean particle levels across the country are currently around 22µg/m3. Levels in London are around 27µg/m3, though in some hotspots they can be as high as 48µg/m3. Existing measures will see levels fall considerably over the next few years.

  • PAHs: The other main innovation is a "provisional" objective for PAHs to be met by 2010. The Government has followed the advice of the Expert Panel on Air Quality Standards (EPAQS) and adopted an annual mean target of 0.25ng/m3 using benzo(a)pyrene as a marker for the complex mixture of PAHs.

    The objective is considerably more demanding than a limit value of 1ng/m3 being considered by the European Commission (see p 49 ).

    However, the provisional objective will not be subject to control under the LAQM regime and local authorities will not have to introduce specific measures to meet it. The only other pollutant which has been dealt with in this way is ozone. However, ozone is impossible for local authorities to control effectively because much of it originates from transboundary pollution. This argument does not wash for PAHs, which are mainly produced by domestic heating, traffic and certain industrial processes.

  • Carbon monoxide and benzene: For benzene, the Government proposes that EPAQS' long-term target of 3.25µg/m3 as a running annual should be achieved by 2010. It says that this will be difficult to achieve, with around 125 roadside locations predicted to exceed it in 2010 without additional action.

    The objective for carbon monoxide is not as ambitious. The Government has adopted the slightly tighter 8-hour mean limit value set by an EU Directive (ENDS Report 311, p 49 ), but has brought forward the compliance date by two years to 2003. Background concentrations at most urban locations are already in compliance, and no additional measures should be required.

  • Options for compliance: The Government is not committing itself on how the proposed objectives will be met. Instead, it offers a selection of illustrative measures such as mandatory fitting of particulate traps to heavy and light diesel vehicles, the introduction of sulphur-free petrol and diesel, more compressed natural gas vehicles and zero-emission buses.

    Industrial Emission abatement options include fitting electrostatic precipitators or flue gas desulphurisation equipment to coal-fired power stations; fitting filters and scrubbers to sites like refineries, steel works and cement plants; and fuel switching away from oil and coal to gas.

    Based on these scenarios, the overall annual cost of meeting the targets is put at between £785 million and £1.1 billion in 2010. The costs are dominated by technologies to reduce particle emissions.

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