I agree that earth-normal atmospheres are overrated. By the time we can cheaply terraform Mars, the inhabitants will have learned to LIKE having an endless supply of near-vacuum. Instead of sprinklers (which can damage things), fires trigger pressure-relief valves that drop the habitat pressure to 0.5 atm; humans can survive lower oxygen partial pressures than most fires. When your farm module gets infested with pests, just drop the pressure until their little carpaces explode. Paint fumes in your newly-renovated apartment? Vent the pressure and offgass the solvents in minutes. Kitchen or bathroom odors? Vent the pressure. All the nasty organic stench will get broken down by the UV and peroxide soil outside; when you compress the external atmosphere to pump it into your agriculture pods, it'll be clean, odorless CO2 and argon.