Thanks for joining @waki and great question! This sounds like a tough situation to be in, but I’m sure there are some ways you can improve your air quality.
Yes, I agree. I don’t think it is a responsibility that should fall on you and I also don’t think it would make that much of a difference since other parts of the vent are likely blocked/dirty too. I guess you could try adding a filter at your end, but since it’s quite dusty anyway I’m not sure how great the airflow would be.
Do you normally run the ventilation system (I’m assuming it’s an extraction system?) or not since it’s dusty? One thing that I used to do in the first apartment I lived in in Korea (similar situation with the bathroom having no windows or an extraction fan) was to keep the bathroom door open at most times so it never got too damp.
Overall, your PM2.5 levels look quite good (but lower is always better!). This brings us to VOCs… which are very tough. In short, I wouldn’t pay too much attention to VOC readings from low-cost monitors unless there is a significant/regular trend. I’ve had quite a few discussions on this topic here already, and I would recommend reading these two posts for more details:
If you’re worried about VOCs and HCHO in particular, I wouldn’t look at air quality monitors, but rather getting a professional test (I discussed that a bit in the thread link above) as they are far more accurate and will likely put your mind at ease. They also tend to be affordable in most countries.
When it comes to radon, then yes, I think a monitor could be a good choice! Since you already have the Temtop monitor, would you be primarily looking for a radon monitor, or would you like an all-in-one device (like the Airthings View Plus)?