Particulate matter concentration measuring apparatus

摘要

A disclosed particulate matter concentration measuring apparatus (40PM) measuring concentration of particulate matter in exhaust gas passing through an exhaust line (21) includes an exhaust gas collecting line (41A) branched from the line (21), a particulate matter detection filter (42A) provided in the line (41A), a differential pressure sensor (42B) sensing differential pressure between the filter (42A), a passage wall (42E) disposed to flow exhaust gas to a downstream side of the filter (42A), an inlet side passage (42a) through which exhaust gas passes into the inlet side passage (42a) flowing into the filter (42A), and an outlet side passage (42s) though which the exhaust gas passed through the filter (42A) passes, wherein the outlet side passage (42s) has a cross-sectional area 1.0 times or more larger than that of the inlet side passage (42a).