Penetration of diesel exhaust particles (DEPs) through fibrous filters produced using melt-blown technology

Abstract

It is well known that diesel fumes are carcinogenic to humans and may cause inflammation of the respiratory tract, cardiovascular problems, etc. Diesel exhaust particles (DEPs) occurring in diesel fumes are fractal-like aggregates with diameters ranging between 10 and 2000 nm, with various compounds adsorbed on their surface. The fractal-like structure of DEPs and their nanosize leads to the problem of theoretically predicting the DEPs’ filtration efficiency. Thus, experimental studies on effective protection against DEPs as well as theoretical modeling are essential. This study analyzes both experimentally and theoretically the mechanical and electret filters and their potential effectiveness in the filtration of DEPs. The theoretical analysis of the filtration process on fibrous fabrics was performed using classic filtration theory, assuming that the filtration layer can be treated as a system of a single fiber located in the Kuwabara cell. The experimental results show that the fibrous filters, produced using melt-blown technology, provide a high level of protection against DEP aerosols (93 %–99 %). The obtained filtration efficiencies are (in some cases) even higher than requested for particulate respiratory half-mask type 2 (made from a fibrous filter). However, the theoretical results obtained using classic filtration theory indicate lower filtration efficiencies than the experimental ones.