As others of posted the big difference here - and also the big challenge - is that indoor air is a definitively NOT a public service. It requires a slew of reg

As others of posted the big difference here - and also the big challenge - is that indoor air is a definitively NOT a public service. It requires a slew of regulation, enforcement bodies, and - from a US perspective - profitability for litigation attorneys. Again with a US slant, ADA is the obvious legislative model for similar clean air regulations. So it's possible, just more challenging than public sewage.