Progress report on Particular Matter Pollutants (PMP) Informal Working Group activities for GRPE-95. Updates on proposals for a new Supplement to UN R179, a new UN Regulation on brake replacement parts, additions to GTR 24 for light-duty vehicles with limited speed, a new GTR for heavy-duty brakes, and a new UN Regulation for heavy-duty vehicle brakes. Reports on ongoing inter-laboratory studies for calibration procedures and brake emissions testing. Discusses technical developments in brake testing facilities, electromechanical brakes, and conformity of production procedures.