The trick is to adjust only the parameter you were targeting. Say you also change temperature and humidity and they are the real culprits, or big contributors. This is why the unethical method would be more precise because conceivably it's easier to introduce specific pollutants in the experiment.
Of course this would be irresponsible so I'm hoping that by combining data from multiple studies and getting a better grip on how to control the test environment to selectively adjust (remove) only the studied parameters (pollutants) we can still get a good idea of what's happening.
Would it be unethical to provide a free filter that takes out all particles, then re-adds one specific pollutant back into the air at the exact same level?
On the one hand, the machine is specifically administering the pollutant to humans; on the other, without the device they'd be getting the exact same and worse.. I'd say yes if offered that for my house and it could help research.
It would definitely be very impractical and expensive to achieve. Also the fact that you add back those particles still feels at least a bit unethical. Definitely not a simple issue.
But using a filter that selectively removes just that pollutant and changes nothing[0] else would probably be the cleanest way to do it.
If the result to the user (getting a machine that leaves them with clean air except 1 type of polutant at exactly the level that polutant would be without the machine), is it really different ethically based on whether the machine leaves that polutant or removes then replaces it?
Seems kind of like saying (although this example is certainly less ethical to those of us who oppose murder and death penalties) that there's a difference ethically between killing someone by putting poison into their body vs. killing them by preventing food/water to go into their body.
But as to achieving it, sure I wasn't proposing it as necessarily a good or feasible option - other the little bit of research I did when choosing which air purifier for my bedroom I don't know much about the technology.
I was more just thinking about the ethical question if it were possible, since I can appreciate the argument against it but like I said, I personally would be completely happy for a research team to offer me the hypothetical machine.
This is probably more of a philosophical point. But if you removed all pollutants then by putting one back in you're actually poisoning your subject.
I guess it's the difference between a surgeon operating and taking out 90% of a tumor, and a surgeon taking out the whole tumor then putting a bit back in. But again, I am not an ethics expert, this is just me bouncing ideas.
If you are talking about things like PM10 or PM2.5, then it would be infeasible to re-add an identical or even plausibly equivalent pollutant, unless it's the one removed.
By definition, it is a concentration of things small and solid. Whether they are ground tires, engine soot, rock/dirt, pollen, mold spores or powdered cyanides, they are counted the same.
If you wish to replicate pollutants, then consider ethical implications of: Looks the same to me, my colleagues and everyone I know, yet it's not, or is it?
Of course this would be irresponsible so I'm hoping that by combining data from multiple studies and getting a better grip on how to control the test environment to selectively adjust (remove) only the studied parameters (pollutants) we can still get a good idea of what's happening.