Instrumental and bio-monitoring of heavy metal and nanoparticle emissions from diesel engine exhaust in controlled environment

In the present article we characterized the emissions at the exhaust of a Common Rail (CR) diesel engine, representative of lightduty class, equipped with a catalyzed diesel particulate filter (CDPF) in controlled environment. The downstream exhausts were directly analyzed (for PM, CO, CO2, O2, HCs, NOx) by infrared and electrochemical sensors, and SEM-EDS microscope; heavy metals were chemically analyzed using mosses and lichens in bags, and glass-fibre filters all exposed at the engine exhausts. The highest particle emission value was in the 7–54 nm size range; the peak concentration rose until one order of magnitude for the highest load and speed. Particle composition was mainly carbonaceous, associated to noticeable amounts of Fe and silica fibres. Moreover, the content of Cu, Fe, Na, Ni and Zn in both moss and lichen, and of Al and Cr in moss, was significantly increased. Glass-fibre filters were significantly enriched in Al, B, Ba, Cu, Fe, Na, and Zn. The role of diesel engines as source of carbonaceous nanoparticles has been confirmed, while further investigations in controlled environment are needed to test the catalytic muffler as a possible source of silica fibres considered very hazardous for human health.