Nitrogen dioxide levels over Europe decreased by between 20% to 30% on average across Europe between 2005 and 2010, and air quality over the continent improved, say researchers.
Satellite observed trend in nitrogen dioxide (NO2) over Europe and the industrial production index reported by the statistical office of the European Union (EUROSTAT) (source: Patricia Castellanos)
The new research, published in the Scientific Reports, suggests these decreases come from a mix of the impact of both national and EU wide environmental policy and the global recession.
The study found that in 2009, NO2 concentrations were at least 10% lower than 2005 values and as high as 20-40% lower in industrialised regions in Germany, Italy’s Po Valley, north-east Spain and large cities.
This coincides with the change in anthropogenic activity in Europe from sharp downturns in GDP, industrial production and consumption experienced during the economic downturn of 2008-2009, according to researchers.
The study also found that reductions in NO2 generally slowed towards the end of 2010, possibly indicating the beginning of economic recovery.
The researchers found gradual reduction of nitrogen emissions being reported over the period to 2004 and 2008 despite economic growth, indicating the success of environmental policy.
The non-linear concentrations seen in 2008-2009, however, suggest that some of the air quality improvements by the end of 2010 were independent of EU environmental policy.
Some of the highest reductions were seen in areas with large power stations, including in south-western Germany, eastern Germany along the Polish border and north-western Spain, suggesting the installation of NOx emissions controls or more efficient combustion techniques.
There were also increases in NO2 seen around the largest cities in the UK, Ukraine and Turkey – corresponding to new or upgraded power stations.
In the UK, increases in the London region could represent rises in vehicle activity around the city from motorway improvements and the congestion charge, according to the study.
In 2009, the report found sharp declines in NO2 between the UK and continental Europe, as well as along the coastlines of Belgium, France, the Netherlands and Europe, which they believe is due to sharp declines in shipping activity from the recession.
Overall in many large European cities, emissions reductions in one year of the economic downturn outweighed roughly four years of policy improvements, says the study.
The researchers aimed to highlight the non-linear nature of emissions reductions, both reflecting policy measures and economic activity across the continent.
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