The FDA would likely have faced legal challenges to a menthol ban
The FDA, after being sued for inaction on the said issue, reported in April 2021 that it is slated to remove menthol from the said tobacco products
Nielsen, Blackwell Science, CORESTA, p398-439 Baker RR (2006) Smoke generation inside a burning cigarette: modifying combustion to develop cigarettes that may be less hazardous to health
(@ ~5 ACH) The Alen Flex occupies the sweet spot between the gas-phase specialists (IQAir, Austin Air) and the high-speed particle removers (LEVOIT)
It is a less harmful alternative to smoking, as it does not produce any tar or carbon monoxide
Some of them are more from the academic point of view, some of them from the journalistic point of view, but they are very good and they have a lot of information