{HEAD ~ A source} of {TAIL ~ fugitive gases} is directed to the air intake of the engine 
of
{ HEAD ~ A source } of { TAIL ~ fugitive gases } is directed to the air intake of the engine
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH