  We present maps tracing the fraction of dust in the form of polycyclic
aromatic hydrocarbons (PAHs) in IC 5332, NGC 628, NGC 1365, and NGC 7496 from
JWST/MIRI observations. We trace the PAH fraction by combining the F770W
($7.7~\mu$m) and F1130W ($11.3~\mu$m) filters to track ionized and neutral PAH
emission, respectively, and comparing the PAH emission to F2100W which traces
small, hot dust grains. We find average $R{\rm_{PAH} = (F770W+F1130W)/F2100W}$
values of 3.3, 4.7, 5.1, and 3.6 in IC 5332, NGC 628, NGC 1365, and NGC 7496,
respectively. We find that H II regions traced by MUSE H$\alpha$ show a
systematically low PAH fraction. The PAH fraction remains relatively constant
across other galactic environments, with slight variations. We use CO + H I +
H$\alpha$ to trace the interstellar gas phase and find that the PAH fraction
decreases above a value of I$_{H\alpha}/\Sigma_{H~I+H_2}$ $\sim~10^{37.5}$ erg
s$^{-1}$ kpc$^{-2}$ (M$_\odot$ pc$^{-2}$)$^{-1}$, in all four galaxies. Radial
profiles also show a decreasing PAH fraction with increasing radius, correlated
with lower metallicity, in line with previous results showing a strong
metallicity dependence to the PAH fraction. Our results suggest that the
process of PAH destruction in ionized gas operates similarly across the four
targets.
