If you have ERVs and filters then amazing. That's still outdoor air.
Yes you have to take into account running an air filter for PM2.5, closing the window while a truck is idling outside, running your humidifier or dehumidifier if you want.
But you need fresh air coming in somehow, at a certain rate. There's no way around it. Pollution in terms of VOC's, and CO2, is always higher indoors than outdoors, because things indoor generate it and don't remove it.
> Most people don't, and cracking a window is the only option.
It's not usually the only option. Installing an ERV is an option for the more than half of the population that owns their own property in the US, and an ERV will save money and pay for itself compared to opening your windows, in addition to the other benefits.
For renters, that's where the window units I mentioned come in, but there aren't as many options there as I would hope yet. If people don't ask for ERVs en masse, then apartments won't offer ERVs as a benefit to attract tenants unless they are legally required. Helping people understand that options exist seems like the first step to changing things. Ideally, even window-unit ERVs wouldn't be the only option for renters. Nearly 90% of households in the US have air conditioning now (which I believe includes rentals), because people asked for air conditioning and were willing to pay for it. ERVs have the added benefit that they don't just make things better, but they should pay for themselves in energy savings too. Maybe I'm too optimistic. I believe the 2024 IECC building codes make ERVs mandatory in new construction in climate zones 6 through 8, as one example of a change that is coming.
Yes you have to take into account running an air filter for PM2.5, closing the window while a truck is idling outside, running your humidifier or dehumidifier if you want.
But you need fresh air coming in somehow, at a certain rate. There's no way around it. Pollution in terms of VOC's, and CO2, is always higher indoors than outdoors, because things indoor generate it and don't remove it.