Ozone pollution on the rise

Ozone pollution is rising across Britain, especially in the cities, the government's air quality statistics for 2006 show.

Following a weekend of sunny weather that caused ozone-rich photochemical smog to form across urban areas in Southern England, statistics released on Tuesday indicate an upward trend in ozone levels over the last two years.

Urban levels of ozone averaged 61 micrograms per cubic metre (ug/m3) in 2006, compared to 57 in 2005 and 44 in 2004, continuing an increasing long-term trend since 1992 when regular measurements began.

Ozone pollution is produced when sunlight causes nitrogen oxides from traffic fumes react with volatile organic compounds, and thus is highest in urban areas, peaking in times of sunny, windless weather. Warm, sunny weekends when city dwellers head for the countryside produce the perfect conditions for ozone formation – a mix of traffic fumes and sunlight.

High ground-level ozone levels cause lung irritation as well as damaging crops.

In rural areas ozone levels rose from 68 ug/m3 in 1993 to 74 ug/m3 in 2006, but there is no clear trend, the government statistics show.

The ozone data released on Tuesday is part of the Government’s “air quality indicator for sustainable development,” alongside data on particulate matter (PM10) pollution levels and the number of days in the year when a cocktail of five key pollutants is particularly high.

Ozone and PM10 are targeted as the two pollutants thought most likely to cause serous health impacts.

Particulate matter pollution rose slightly over the last two years, although overall PM10 levels have been falling in earlier years since records began in 1993.

Pollution peak days, when moderate to high levels of a mix of five pollutants – carbon monoxide, nitrogen dioxide, ozone, fine particles (PM10) and sulphur dioxide – were recorded are increasing in the countryside as well as in cities, but are weather-dependent and so vary strongly from year to year.

Goska Romanowicz

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