November 2000, Pollution watch
When the National Air Quality Strategy was initially launched in 1997 the air quality objective for particulates was set at 50 m g/m3, measured as a running 24-hour mean, to be achieved by 2005. However, to avoid the cost implications of enforcing rigid, 100% compliance to the objective an allowance was made for PM10 levels to exceed the objective for four days per year (subsequently changed to 35 days). This 'breathing-space' was intended to allow for uncontrollable natural sources, adverse weather conditions and national festivals such as Bonfire night.

Despite the end of October and beginning of November being characterised by gale-force winds and torrential rain over most of the country there was a lull in the storms on the fifth of November itself. This year the fifth fell on a Saturday, so that for once the majority of bonfires and firework displays occurred on the same night, rather than being split between Guy Fawkes' Night itself and the closest weekend. Combined with the cold, calm conditions this led to elevated levels of PM10 across much of the country. Levels of particulates exceeded the air quality standard at 13 sites up and down the country, from Leeds to Southampton. London was particularly bad with 'high' levels of particulates being recorded over 17 hours at Bexley in South London and 'moderate' levels at seven other stations across the city for much of the day. By the next day the winds had picked up again and the pollution dispersed. Aside from this event levels of air pollution were low for most of the month aside from a few localised problems.
Tim Chatterton and Steve Dorling are air quality researchers at UEA