In implementation of article 4 of Directive 96/62/EC, this Directive (i) establishes limit values for concentrations of benzene and carbon monoxide in ambient air with a view to avoiding, preventing or reducing harmful effects on human health and the environment, (ii) provides for the assessment of concentrations of the above-mentioned pollutants on the basis of common methods and criteria, and (iii) makes rules to ensure that adequate information on such concentrations is obtained and made avai