the maximum permitted mass concentration of particulate matter below 10 microns in ambient air is regulated within the EU, it is called the PM10 fraction.See the following link:
Also regulated is the maximum permitted content of several metals and other elements such as Ni, Cd, As ... Althoug there are methods available (e.g. PM10 sampling devices and ICPMS for chemical analysis) I think it is worth doing research in the field in order to increase accuracy, flexibility (temporal and spatial) and sensitivity.
Yes, i think its worth to know the variation in level of carcinogenic elements in respirable dust, for both ,public and workers engaged in occupational settings .