Particle filter test procedure and quality standard for diesel engines

A new approach is needed to test particle filters for retrofitting Diesel engines. Considering the toxicity of the particles as also the physical and chemical attributes of particle filters, the optimal scheme is to test the components themselves independent of the deployment. That scheme ensures the highest effectiveness with least effort. It also enables evaluation of worst-case situations and assesses the hazards of secondary emissions. The Swiss standard SNR 277 205, which mandates the VERT test procedure, is a first step in that direction. Occupational health specialists have studied the toxicity of ultraflne particles for more than 100 years. Extremely toxic are the particles intruding into the lung. Larger particles, which are always naturally present, are intercepted in the upper respiratory paths. The body then expels these larger particles rapidly via the mucus and cilia. The new manmade particles less-than l mi m, however massively intrude into the fine pulmonary alveoli, which do not have the cleansing mechanism. The targeted efficiencies for evaluating modern filters are evident from the progress achieved. Many filters have filtration rates exceeding 99.9%, albeit the directives [4] only require 97%.