3. General conclusion

The introduction of grids in the materials does not fundamentally alter the emission factors. The most decisive variables seem to have more to do with the use of the planer (i.e. machine speed, milling speed, conveyor belt speed, watering, suction, planing depth, etc.). However, the influence of the grids on the particle size distribution of emissions is not negligible, especially with regard to micrometric particles. In this case, emissions are significantly lower for particles with diameters greater than 3 µm. The use of warm asphalt concrete seems to reduce this reduction, but this remains to be confirmed.

Observation of the heaps of planed material reveals: 1) the presence of centimetric fragments of grids and 2) glass fibres ranging from several millimetres to several tens of micrometres in length. Some fibers are trapped in a gangue of aggregates. However,...