Please forward this to the City of Philadelphia.Proper ventilation is needed a range hood and it must be properly sized.
It is important that your installer conducts a worst-case depressurization test. This combustion safety test determines if any non-sealed combustion appliances will backdraft or spill combustion products into the living space. Tell your installer this test should use an established procedure such as Appendix D of the International Fuel and Gas Code or ASTM E1998 "Guide for Assessing Backdrafting and Spillage from Vented Combustion Appliances"
Please forward this to the City of Philadelphia.
There are probably well over 1/4 million gas ranges w/o any ventilation whatsoever there.
Locals find that acceptable, probably as a result of brain damage from combustion products in their homes.