Provisional data for air quality last year was released by the environment department (DEFRA) on 3 February.1
Average urban background coarse particulate (PM10) levels were 19 micrograms per cubic metre in 2010 and have not changed since 2008. Roadside levels rose by 1µg/m3 to 23µg/m3, bucking the downward trend.
But these figures may not be reliable. Measurements from sites using older, less accurate, equipment have not yet been corrected.
Rural and urban background levels of ozone fell for the second year in a row and are now down to 67µg/m3 and 53µg/m3 respectively. The long-term increase in urban levels may, therefore, have ended. Rural levels have remained fairly static since the late 1980s.
Ozone pollution is worse in the countryside. These areas have lower levels of ozone-destroying nitrogen oxides (NOx) than towns and cities.
This explains why rural monitoring stations detected an average of 22 days of moderate or higher levels of air pollution, compared with only ten in urban areas. Although these figures are very low, no clear long-term trend can be seen.