I believe it's more complicated than you think to come up with general answers.I cant see that being a thing standing in the way of running reasonable and accurate tests. If they can measure air quality in a kitchen, exhaust emissions, cigarette smoke and list with accuracy, then the technology is there already to measure what vapers are inhaling. No need to to spend half a century procrastinating, we have the technology. Wouldnt take more than a week or two to produce the data at any modern lab, depending on their work load. I cant imagine it even being an expensive or difficult exercise in 2019.
Are the results from a juul or other device that runs at a single-digit wattage going to be comparable to the results from an rda run at a triple-digit wattage? Will there be actual vapers present to sample the setups to ensure that they're being run in a realistic manner and not overheated and dry puffed? What PG/VG ratio will be used? What flavorings will be used in the liquids and at what percentage?
We know from experience that such studies can show very bad results (formaldehyde, etc.) if the devices are pushed too hard, in a manner that real vapers simply don't. We know that some flavoring ingredients have the potential to be problematical, and I don't just mean diketones.
The variety of gear, liquid compositions, and today even nic (salt) formulas, make this a far bigger task than it appears at first glance.