Membrane based apparatus for measurement of volatile particles

A method of separating vapors from particles comprising:

• collecting particulates of an exhaust gas from an exhaust plume of an engine;
• heating the particles of the exhaust gas in a temperature controlled chamber of a vapor particle separator, wherein a temperature of the temperature controlled chamber is selected to desorb gas phase molecules from the particulates of the exhaust gas;
• introducing the particles of the exhaust gas and the gas phase molecules that were desorbed from the particles of the exhaust gas into a separation chamber of the vapor particle separator that includes a particle passageway to a particle exit in a first direction and an vapor passageway to a vapor exit in a second direction, wherein an interface between the particle passageway and the vapor passageway is provided by a micro porous membrane;
• and
• applying a cross flow to the separation chamber to draw the vapors from the vapor exit of the vapor particle separator and to draw the particles of the exhaust gas from the particle exit of the vapor particle separator.