In the air quality directive (2008/EC/50) the EU has set two limit values for nitrogen dioxide (NO2) for the protection of human health: the NO2 hourly mean value may not exceed 200 micrograms per cubic metre (µg/m3) more than 18 times in a year and the NO2 annual mean value may not exceed 40 micrograms per cubic metre (µg/m3). These limit values come into force for concentrations measured from 1.1.2010 so during 2009 a margin of tolerance equal to an annual mean value of 42 micrograms per cubic metre (μg/m3) is still in place.
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Keep your dog on a lead if it is likely to run off and disturb wildlife.
In particular, be careful of nesting birds in early spring and early summer, and roosting or feeding birds in winter. If you have a dog, keep this in mind when you're taking it for a walk!
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