I do not know of an established way to do this, but it would certainly be a good indication to measure and publish the following things:
What is the ratio of hydrogen to carbon? The more hydrogen, the more water is produced. Usually this means more energy density (compare oil to methane). Despite the scare in mass media this is almost irrelevant regarding both health and environmental concerns however (water vapour and carbon dioxide are very comparable in regards to greenhouse effects). This can used to guess the next point:
How much 1) soot 2) carbon monoxide is produced in a particular engine (or oven or whatever). Something like nitrocellulose burns rather clean even if there is not much oxigen present.
Are there other elements present(for example nitrogen, sulfur etc) Those certainly burn much "dirtier", often producing irritating gases (nitrous gases etc.) This is probably the greatest concern regarding health.
As a side note: One should also consider whether there are volatile things which are unhealthy, benzene rings come to mind.