The Directive establishes the first ever limits on ambient concentrations of ultra-fine particles (PM2.5), which have the most damaging health impacts. But debate over the limit and its deadline has been considerable ever since it was proposed (ENDS Report 369, pp 44-45 ). Some MEPs have tried to weaken the new rules (ENDS Report 381, p 47 ).
The agreement limits PM2.5 to 25 micrograms per cubic metre by 2015. Member states will get a margin of tolerance for meeting the limit, starting at 20% above the target. This will be phased out gradually by 2015. A provisional binding limit of 20µg/m3 by 2020 has also been agreed.
For larger fractions of particulates, PM10, the existing 40µg/m3 limit remains.