Range from Full dE/dx for 5.5MeV alpha using Geant4 10.7.2
Air has identical composition and density to G4_AIR
Air Original is Air composition (N, O only, density 1.29 mg/cm3) from original source code of TestEm1
default EM physics is emstandard_opt3 (in PhysicsList.cc)
SRIM Results are from Ziegler et al.'s SRIM-2008.04 program (http://www.srim.org/)

EM Physics List        Air Original      Air               G4_AIR
                       N,O 1.29 mg/cm3                     1.20479g/cm3

emstandard_opt0        ---               4.294 cm          4.295 cm
emstandard_opt1        ---               4.294 cm          4.292 cm
emstandard_opt2        ---               4.295 cm          4.294 cm 
emstandard_opt3        3.923 cm          4.193 cm          9.291 mm
emstandard_opt4        ---               4.194 cm          9.289 mm             
empenelope             ---               4.194 cm          4.192 cm             
emlivermore            ---               4.194 cm          4.192 cm      

SRIM Program           3.864 cm          4.476 cm          4.476 cm