In compliance with the new EU Air Quality Directive, which entered into force in 2008, Portugal requested additional time to meet the PM^ standard. The Commission has decided to send a final written warning to three Member States that have not met the PMjq standard, including Portugal. The IQAr, calculated for specified zones/agglomerations, is determined by the worst pollutant concentration measured at one or more monitoring stations. Pollutants considered in the calculation include N02, 03 and PMi0.