Kinetics and nitro‐products of the gas‐phase OH and NO₃ radical‐initiated reactions of naphthalene‐d₈, Fluoranthene‐d₁₀, and pyrene

The kinetics and nitroarene product yields of the gas‐phase reactions of naphthalene‐ d 8 , fluoranthene‐ d 10 , and pyrene with OH radicals in the presence of NO x and in N 2 O 5 NO 3 NO 2 air mixtures have been investigated at 296 ± 2 K and atmospheric pressure of air. Using a relative rate method, naphthalene‐ d 8 was shown to react in N 2 O 5 NO 3 NO 2 air mixtures a factor of 1.22 ± 0.10 times faster than did naphthalene, with the 1‐ and 2‐nitronaphthalene‐ d 7 product yields being similar to those of 1‐ and 2‐nitronaphthalene from naphthalene. From the measured PAH concentrations and the nitroarene product yields, formation yields of 2‐, 7‐, and 8‐nitrofluoranthene‐ d 9 and 2‐ and 4‐nitropyrene of 0.03, 0.01, 0.003, 0.005, and 0.0006, respectively, were determined from the OH radical‐initiated reactions. Effective rate constants for the reactions of fluoranthene‐ d 10 and pyrene with N 2 O 5 in N 2 O 5 ;NO 3 NO 2 air mixtures of ca. 1.8 × 10 −17 cm 3 molecule −1 s −1 and ca. 5.6 × 10 −17 cm 3 molecule −1 s −1 , respectively, were derived. Formation yields of 2‐nitrofluoranthene‐ d 9 and 4‐nitropyrene of ca. 0.24 and ca. 0.0006, respectively, were estimated for these reaction systems. 2‐Nitropyrene was also observed to be formed in these N 2 O 5 NO 3 NO 2 reactions, but was found to be a function of the NO 2 concentration and, therefore, would be a negligible product under ambient NO 2 concentrations. These product and kinetic data are consistent with ambient air measurements of the nitroarene concentrations.