Which of the following appears to be true? a) increasing aerosol viscosity has no impact on the distance polycyclic aromatic hydrocarbons travel. b) no clear relationship between aerosol viscosity and the distance polycyclic aromatic hydrocarbons travel exists. c) increasing aerosol viscosity leads to an increase in the distance polycyclic aromatic hydrocarbons travel. d) decreasing aerosol viscosity leads to an increase in the distance polycyclic aromatic hydrocarbons travel.