Given the increasing awareness of air filtration and ventilation and the impact it has on transmission of infections like COVID it is increasingly becomming important to people, espeically those who are immunocompromised to know if a venue or building will clean the air.
This is my first time putting together a proposal so I apologise if there are any glaring mistakes or breaks from convention. At the moment it is a v rough draft. Please feel free to either leave feedback here or on the talk page either on specific components of the tag or if you believe there is a better way to integrate this data than a new tag.
I am not familiar with this topic. Are there examples of buildings or amenities having parts (eg some rooms/floors) with air filtering and other parts without? If so, a tag like air_filtration=limited or =partial could be useful, as a third option besides yes and no.
I agree! I did also add that it can be applied to building:part=yes ways so you could map out specifically where the air filtration is. But knowing coverage from an amenity point of view is a good idea.
Thinking air_filtration=full|partial|none instead of the air_filtration=yes|no, lemme know what you think?
Many air conditioning systems have filtration as one of their functions. The obvious exceptions being some ‘cassette’-type installations that just recirculate air after heating / cooling / dehumidifying it.
Then there is the matter that while the system might be designed to deal with pollen, it might not be particularly good at dealing with viruses. And then the question of whether it is maintained properly.
As mentioned, verifiability would be a real issue.
I have to triple down on the unverifiability of this.
In industrialized countries it is a forgone conclusion that just about any building with a mechanical ventilation system, i.e. which uses at least one air handling unit (AHU) with one or more fans in it, will have filtration. At the very least to protect the equipment itself. As such, respectfully, basically every building could be tagged with the proposed air_filtration=yes, rendering the tag completely redundant.
It is impossible for anyone to field-verify the level of filtration in a building without access to the mechanical room(s). You couldn’t possibly guess at this.
Likewise with the building pressurization. Just about any building will be designed to be slightly positively pressurized, overall. Some rooms will be negatively pressurized with respect to the adjacent rooms, e.g. toilets or locker rooms. (Or something much more heavily controlled and monitored, like an airborne infectious isolation room in a hospital, which is designed to keep infectious patients isolated from the rest of the population and will have HEPA filtration on the exhaust out of the room.) There is no way for you to verify the pressurization, short of direct access to a building automation system with active pressure monitoring. This is something no mapper could ever expect to have access to.
To address verifiability concerns: Some air purification systems are very visible and all it takes is looking up a brand name to find out what type of air purification they use. A lot of ‘after market’ UV-C purifiers are often installed in big boxes on a wall or high up on the wall like a commercial air conditioning unit. Portable air conditioning units, especially those like the ones Breathe Easy Sheffield lend to event organisers are very recognisable. I plan to grab photos of what I mean in future.
I’m also planning a scheme locally to get stickers made for venues to signal that they are filtering their air and what is specifically filtered as both pollutants and airborne pathogens are of increasing concern. I know of a few events that already advertise they clean air to prevent the spread of infection, it probably won’t be that much of a jump for a venue to begin advertising air filtration/ventilation as a selling point.
Beyond that while the average surveyor probably can’t verify the quality of air in a space a more equipped surveyor definitely could measure the levels of pollutants and the number of respiratory drops (the main way airborne pathogens are transmitted) in the air and could even do so at the exit to a vent. I think this would need a different tagging scheme seeing as the verifiable thing there would be the quality of air not how it is filtered but it’s not out of the question and is verifiable. Personally I don’t want to go down that road though.
RE @VictorIE and different types of filtration: If a system can filter out pollen it will likely filter out respiratory particulates which are much bigger than the pathogens that it carries. Any kind of mechanical filtration will help reduce the transmission of pathogens. And there are sub-tags for the different types of filtration as well as a rating tag (though I’m looking at changing/removing this) to specify the type if filtration present.
Regarding filtration being a foregone conclusion (@hoserab): I can see from your HDYC that you seem to mainly edit in North America. While in a lot of Canada and the US AC systems or furnace based systems with air purification are the norm that is not true in every industrialised nation. Here in the UK air conditioning is not nearly as commonplace so having air filtration is not a foregone conclusion. We also shouldn’t be designing tags with only the industrialised world in mind especially when a lot of the developing world and global south relies so heavily on OSM for any kind of maps at all. Having air filtration at a medical facility is not always an assumption that can be trusted and for immunocompromised people living in countries like that knowing where has filtration is probably incredibly critical information.
Regarding Presurisation verifiability: The tag is meant to signal when pressurisation is intentional for the purposes of air quality or for the purposes of preventing leaks from inside into the environment. Buildings experience minor pressure fluctuations as does the outside world, this tag and scheme isn’t concerned with that. If part of the design of a space involves keeping it at a certain pressure to keep contaminants in/out then it will be incredibly obvious when entering that space.
I think this covers everything brought up since my last reply, thank you for all your contributions to this discussion!
EDIT: Forgot to add, gonna be adding a bunch of changes to the current proposal when I’ve had a think about all the conversations I’ve had about it and gotten a little bit more feedback. Will ping specific users in here when I think that their concern has either been addressed or added to confirm they are convinced the issue is resolved.
Yes, I do map things in Canada (and a smattering of the US), because those are places I’ve been and have personally verified.
I’m also a building services engineer, licenced as a professional in multiple Canadian jurisdictions, who designs HVAC systems in buildings for a living.
Air conditioning, which is to say mechanical cooling, is also not all that commonplace in homes here, and in many larger buildings (e.g. schools, which are empty all summer anyway, so why bother cooling them when no one is there?). However, ventilation is a basic building requirement. I understand that in British homes and other small buildings you may not have mechanical ventilation (relying instead on natural ventilation through windows), but in larger buildings I can (mostly) guarantee you do. Your building regulations require it (see “Approved Document F” and CIBSE Guide B2). And if you have a ventilation system you have filtration, if only to protect the air handling unit itself from the accumulation of dust and debris.
With all due respect I think you’re thinking of tagging places that have some sort of portable or supplementary “air purifier”. I’ve taken this snapshot from that “Breathe Easy Sheffield” website, and circled what I think you mean:
That space is mechanically ventilated, and therefore already has air filtration of some sort.
As I wrote before, most buildings with mechanical ventilation systems will be designed for a slightly positive pressure relative to the outdoors, precisely to keep contaminants out. (And to prevent damage to the building envelope!) You think it’s “incredibly obvious” but truth is the opposite: a well-designed and balanced ventilation system will make this pressurization imperceptible to human senses. We’re talking 5-10 Pa, or about 0.05-0.10% of standard atmospheric pressure.
I fully agree here. Talking about air filtering, a boolean is kind of useless and the filtration grade you might not be able to verify. Even if there is a device accessible to mappers having a type plate indicate a filtration grade, still the device can be simply bypassed/deactivated/…
I’m not loving how this discussion is going, and it’s beginning to drain more mental energy than I’m willing to invest given the lack of collaboration. I don’t want to risk burnout with OSM again, so I’m going to abandon this proposal and potentially work on pathogen control tagging in the future without air purification or ventilation components.
I still think air ventilation and filtration tags would be useful. Especially here in the UK, where only ~20% of schools have mechanical ventilation due to building age. I just don’t have the capacity to advance this proposal under the current discussion dynamics without risking burnout.
I’d also rather not have people using Breathe Easy Sheffield’s images without their consent and don’t particularly love the idea of having to explain why their volunteers have been posted on a random forum in a discussion they were not involved in.
Anyone who wants to take up this proposal or use it in any way is more than welcome to do so.
One solution I suggested is to change air_filtration= to air_purifier= , limiting the proposal to “portable” but permanent or installed devices in rooms. Would this be acceptable to the skepticism/opposition on verifiability?
For your schools need alone, I have found in wild, and used ventilation= with =natural vs =mechanical etc, mainly for tunnel (in case anyone doubts this, it’s verifiable from jet fans, ventilation shafts, and air duct openings)
Late to this, but worth noting there’s existing tagging in this space that wasn’t referenced above.
air_conditioning=* is already a de facto key, documented on the wiki and in use on libraries, restaurants, cinemas, apartments and hotels. It’s defined as covering mechanical systems that remove heat and moisture from an occupied space, which is the same class of equipment hoserab was describing (any AHU will have filtration to protect itself, if nothing else). Given that overlap, it might be worth asking whether “does this space filter its air” should live as a subtag of air_conditioning=* (something like air_conditioning:filter=*) rather than as a standalone air_filtration=* key. That would also sidestep some of the verifiability objections, since you’re not asserting a new fact about the building, just qualifying one that’s already tagged.
On ventilation=natural|mechanical: worth flagging this isn’t actually a documented general wiki key. It’s seen informal use on tunnel ventilation shafts, but there’s no established page defining it for buildings, so proposing it for schools would effectively be extending a niche infrastructure tag into a new domain rather than reusing a settled scheme. That’s not necessarily a problem, but it should probably be argued for explicitly rather than assumed as “already in use”.
Separately, since there’s no existing air_filtration or air_purifier key to collide with, a narrower air_purifier=* scoped to visible, portable/installed units (as CanopyFalls originally suggested) wouldn’t run into a naming clash, and sidesteps most of the verifiability arguments raised, since a mapper can actually see the unit on the wall.
As I understand, what @CanopyFalls is mainly talking about are dedicated air purifier. They just suck air from within a room through a filter and push them back in the same room. There are also in room humidifier and de-humidifier or chillers (where you put ice in) and of course also heaters.
If someone want’s to put effort in, it’s worth to think about a schema covering all the air handling stuff.
Especially on the purification side the range goes somewhere from “some filter” to “clean room in a lab”
The qualification would have the same verifiability concerns though, wouldn’t it? (How is one supposed to verify the kind of filters an aircon is equipped with?)
