The European Environment Agency (EEA) report finds that ground-level ozone pollution levels remain unchanged despite Europe reducing emissions of the precursor air pollutants that cause it.

The report says: “Ground-level ozone has become a hemispheric or even global air pollution problem.”

Measurements at European sites show background ozone concentration has increased by six per cent or two parts per billion each decade since 1980. The report warns this is “expected to rise further”.

And, it says climate change “could also lead to increased ground-level ozone concentrations in many regions of Europe”.

The EEA calls for global action to combat the problem.

“Ozone is an important greenhouse gas, ranked third behind carbon dioxide and methane,” the report says.

“There are therefore good arguments for integrating ozone abatement into local and regional, but also global strategies and measures addressing air pollutants and greenhouse gas emissions simultaneously.”

Ground-level ozone is among the most harmful air pollutants.

It is formed when sunlight reacts with pollutants and naturally occurring chemicals in the air. These chemicals are emitted by a range of sources, including vehicle exhausts, industry and natural sources such as plants.

At elevated levels it can cause health problems.

Its effect on peoples’ respiratory systems is blamed for many premature deaths. Children, the elderly and asthmatics are vulnerable.

In 2003 1,582 deaths were attributed to ozone in the UK – a toll expected to rise by 51% to 2,391 in 2020, according to a report from The Royal Society, the national academy of science, published last year.

It also reduces crop yields and quality and damages natural ecosystems.

Last Monday’s (July 20) EEA report examines why ozone levels remain unchanged in many countries despite Europe cutting precursor gas emissions.

“European countries have significantly reduced anthropogenic emissions of ozone precursor gases since 1990,” it said.

“In general, however, ambient air measurements in urban and rural areas of Europe do not show any downward trends in ground-level ozone.”

The EEA study used computer models and data from European air quality database, AirBase, gathered from some 200 stations in 18 countries between 1995 and 2005.

Transport, weather variability and a lack of long term data may all help explain why ground-level ozone concentrations are not falling.

Up to 30% of western Europe surface ozone levels are made up of ozone “imported” in by intercontinental transport, the report says.

Meanwhile, year-to-year weather variations have a “significant impact on yearly ozone levels”. They spiked in 2003, which had a very hot summer.

But, the report authors say the study should be treated with “caution” in the absence of longer term data to overcome these weather variations.

To read the report click here.

David Gibbs

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