▁exchange ▁capacity . ▁In ▁some ▁cases ▁the ▁tum or ▁will ▁fill ▁the ▁al ve oli . ▁ ▁Cav it ary ▁p neum onia ▁is ▁a ▁process ▁in ▁which ▁the ▁al ve oli ▁are ▁destroyed ▁and ▁produce ▁a ▁cav ity . ▁As ▁the ▁al ve oli ▁are ▁destroyed , ▁the ▁surface ▁area ▁for ▁gas ▁exchange ▁to ▁occur ▁becomes ▁reduced . ▁Further ▁changes ▁in ▁blood ▁flow ▁can ▁lead ▁to ▁decl ine ▁in ▁lung ▁function . ▁ ▁Em phys ema ▁is ▁another ▁disease ▁of ▁the ▁l ungs , ▁where by ▁the ▁el ast in ▁in ▁the ▁walls ▁of ▁the ▁al ve oli ▁is ▁broken ▁down ▁by ▁an ▁im bal ance ▁between ▁the ▁production ▁of ▁neut roph il ▁el ast ase ▁( e lev ated ▁by ▁cig aret te ▁smoke ) ▁and ▁alpha - 1 ▁ant it ry ps in ▁( the ▁activity ▁var ies ▁due ▁to ▁gen et ics ▁or ▁reaction ▁of ▁a ▁critical ▁m eth ion ine ▁resid ue ▁with ▁to x ins ▁including ▁cig aret te ▁smoke ). ▁The ▁resulting ▁loss ▁of ▁el astic ity ▁in ▁the ▁l ungs ▁leads ▁to ▁prolong ed ▁times ▁for ▁ex hal ation , ▁which ▁occurs ▁through ▁pass ive ▁re co il ▁of ▁the ▁expanded ▁lung . ▁This ▁leads ▁to ▁a ▁smaller ▁volume ▁of ▁gas ▁ex changed ▁per ▁breath . ▁ ▁Pul mon ary ▁al ve olar ▁mic rol ith ias is ▁is ▁a ▁rare ▁lung ▁dis order ▁of ▁small ▁stone ▁formation ▁in ▁the ▁al ve oli . ▁ ▁Fl uid ▁A ▁pul mon ary ▁cont usion ▁is ▁a