Annual nitrogen dioxide concentrations are likely to exceed legal limits in several areas of Birmingham, according to the draft 'Air Quality Action Plan' produced by the City Council's Environmental Protection Unit (EPU) this year.

Nitrogen dioxide is formed when nitrogen monoxide, a by-product of combustion in car engines, reacts with oxygen in the air. Nitrogen dioxide damages lung tissue and exacerbates existing respiratory problems even at low concentrations. Traffic is typically the source of 65 per cent of nitrogen oxides (NOx) concentrations (industry contributes 5%, and 30% is classed as background).

The EPU reports that, whereas national air pollution measures have allowed Birmingham to meet the required standards for the more familiar nasties, like lead and carbon monoxide, NOx concentrations have been rising over the last few years.

The report identifies a number of 'hotspots' in the city where significant reductions in NOx levels will be needed to meet the Action Plan's objectives by 2005. The hotspots are: Bristol Road, Selly Oak (so long, leafy, healthy campus!); Stratford Road, Sparkhill; the A34 in Sparkhill; Broad Street and Digbeth, City Centre; and the M6 (Brookvale) and A34(M) motorways.

It appears that NOx are bucking the general trend in air quality improvement brought about by the replacement of older, inefficient engines with "greener" equivalents. Climate change is a factor too, as warmer winters favour the formation of atmospheric pollutants. As car numbers increase in the city greenhouse emissions will continue to affect the climate and add to nitrogen oxides formation.

The report clearly indicates that, because of the atmospheric conditions and the trend observed, drastic emissions reductions, i.e. less traffic, will be required to curb nitrogen dioxide levels. A list of 46 actions aimed at improving the situation are listed under the following headings: (a) Reducing vehicle emissions; (b) Improving public transport to reduce traffic volumes; (c) Improving the road network to reduce congestion; (d) Using area planning measures to reduce traffic volumes; (e) Reducing air pollution from industry, commerce and residential areas; and (f) Changing levels of travel demand/promotion of alternative modes of transport. However, the report admits that pollution will remain in excess of permissible levels whatever action is taken.