In the directive 2004/107/EC (Fourth Daughter Directive), the EU has set a target value for nickel (Ni) for the protection of human health: the Ni annual mean value may not exceed 20 nanograms per cubic metre (ng/m3). The target value enters into force 31.12.2012.
EEA standard re-use policy: unless otherwise indicated, re-use of content on the EEA website for commercial or non-commercial purposes is permitted free of charge, provided that the source is acknowledged (http://www.eea.europa.eu/legal/copyright). Copyright holder: European Environment Agency (EEA).
Let the grass grow higher and thus encourage root growth. It will also allow the grass to self-seed. If you mow a path in the middle, it will show that it is indeed meant to be that way as opposed to being neglected.
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