diff --git a/parcel/parcel.jl b/parcel/parcel.jl
index d1862f7627..7e12f6aedb 100644
--- a/parcel/parcel.jl
+++ b/parcel/parcel.jl
@@ -88,8 +88,8 @@ function parcel_model(dY, Y, p, t)
     dqi_dt_new_immers = FT(0)
     if "ImmersionFreezing" in ice_nucleation_modes
         Δa_w = T > FT(185) && T < FT(235) ?
-            CMO.a_w_xT(H2SO4_prs, thermo_params, x_sulph, T) - CMO.a_w_ice(prs, T) :
-            CMO.a_w_eT(thermo_params, e, T) - CMO.a_w_ice(prs, T)
+            CMO.a_w_xT(H2SO4_prs, thermo_params, x_sulph, T) - CMO.a_w_ice(thermo_params, T) :
+            CMO.a_w_eT(thermo_params, e, T) - CMO.a_w_ice(thermo_params, T)
         J_immersion = CMI_het.ABIFM_J(prs, aerosol_type, Δa_w)
         if "Monodisperse" in droplet_size_distribution && "ImmersionFreezing" in ice_nucleation_modes
             r_l = cbrt(q_liq / N_liq / (4 / 3 * π) / ρ_liq * ρ_air)