"Levels of PM2.5 were measured before, during, and after 8 cannabis social-smoking sessions in one 20-m2 household living room" Isn't the amount being smoked r

"Levels of PM2.5 were measured before, during, and after 8 cannabis social-smoking sessions in one 20-m2 household living room" Isn't the amount being smoked relevant? It seems to vaguely compare weed smoke to cigarette smoke without factoring in what normal usage looks like for each. How does this compare to burning incense? Seems like a poorly designed study.