> A difference between 8 and 12 PM 2.5 levels won't change that
Yes, it will, and that's the point I was making.
There are some things that have no harmful affects below certain concentrations, in that they are not toxic at low levels. PM 2.5 particles are not one of those - they are toxic at all levels. It's quite similar, in this context, to ionizing radiation. There is no safe level of ionizing radiation - every X-ray you get will slightly increase your chance of getting cancer. Of course, in the risk/benefit analysis, the risk is low and the benefits for medical X-rays are high.
It's the same with PM 2.5 pollution - every percentage reduction results in fewer health effects and related deaths. It's fine to argue that some level of pollution is worth it to get the benefits of industrialization, but it's simply false to say a reduction from 12 to 8 PM 2.5 levels won't reduce related deaths.
So about ionising radiation: UNSCEAR recommendation is to act as if no threshold effect exist at low doses for indeterministic effects (even though effectively we act as if a 100mSv threshold exists), but the medical literature isn't as clear cut. Precautionary principle should be respected in any cases.
The most recent epidemiology studies (studies on _very_ large cohort) do seems to favour a linear model without threshold (or, if the threshold exists, it is so low ambient radiation is enough to go past it), so I think you're right, but I wanted to nitpick because you wrote it like it was settled science and it's not yet, so I had to look up the PM 2.5 stuff too.
Yes, it will, and that's the point I was making.
There are some things that have no harmful affects below certain concentrations, in that they are not toxic at low levels. PM 2.5 particles are not one of those - they are toxic at all levels. It's quite similar, in this context, to ionizing radiation. There is no safe level of ionizing radiation - every X-ray you get will slightly increase your chance of getting cancer. Of course, in the risk/benefit analysis, the risk is low and the benefits for medical X-rays are high.
It's the same with PM 2.5 pollution - every percentage reduction results in fewer health effects and related deaths. It's fine to argue that some level of pollution is worth it to get the benefits of industrialization, but it's simply false to say a reduction from 12 to 8 PM 2.5 levels won't reduce related deaths.