§ Mr. BercowTo ask the Secretary of State for Environment, Food and Rural Affairs how many days of(a) moderate, (b) high and (c) very high air pollution there were (i) in the United Kingdom and (ii) in Buckinghamshire in each year since 1997; and if she will indicate the suspected causes of high and very high readings. [27790]
§ Mr. MeacherDEFRA operate a National Automatic Urban and Rural Network that currently includes about 120 sites throughout the UK. Data are produced continuously on an hourly basis. Ratified data are available up to 30 September 2001. After this date care must be taken in interpretation of the pollution levels recorded since high measurements may be the result of instrument error that is still to be identified.
An analysis of moderate, high or very high pollution during 1997–2001 has been undertaken to identify the number and severity of such incidents. Pollution at each site is defined according to the pollutant that is in the highest band during the day. The numbers of days in each band for each pollutant in the United Kingdom since 1997 are given in the table.
There are no National Automatic Urban and Rural Network monitoring sites in Buckinghamshire.
Number of days of moderate, high and very high air pollution in the United Kingdom (at one or more sites) in each year since 1997 Moderate High Very high 1997 269 70 14 1998 259 49 12 1999 269 51 15 2000 240 38 7 2001 250 69 19 High air pollution episodes due to ozone are only recorded in the summer months. The pollution is linked to hot sunny weather when industrial and motor vehicle 794W emissions react under these conditions to form ground-level ozone. Light easterly winds sometimes bring this pollution across to the UK from central Europe. If conditions are very still for several days then high pollution can be generated by pollution emissions from the UK only.
High air pollution episodes due to sulphur dioxide are either due to emissions from domestic heating systems (coal or oil), or from industrial processes. The former episodes are measured during the winter in urban areas with significant use of these fuel types. Industrial related incidents can be many miles away from the source of the pollution when the plume from the process comes to ground.
High air pollution episodes due to nitrogen dioxide are related to motor vehicle emissions and, although infrequent, are usually during very cold, still conditions in the winter months.
High or very high particulate matter (PM10) can be from a variety of industrial, motor vehicle, construction or "natural" sources such as Saharan dust, volcanic eruptions, agricultural dust or fireworks.
There are no high or very high CO episodes.