Kinetics of the gas-phase reactions of OH and NO3 radicals and O3 with the monoterpene reaction products pinonaldehyde, caronaldehyde, and sabinaketone

Using a relative rate method, rate constants have been measured for the gas-phase reactions of OH and NO3 radicals with pinonaldehyde, caronaldehyde and sabinaketone at 296+/-2 K. The OH radical reaction rate constants obtained are (in units of 10(-12) cm(3) molecule(-1) s(-1)): pinonaldehyde, 48 +/- 8; caronaldehyde, 48 +/- 8; and sabinaketone, 5.1 +/- 1.4, and the NO3 radical reaction rate constants are (in units of 10(-14) cm(3) molecule(-1) s(-1)): pinonaldehyde, 2.0 +/- 0.9; caronaldehyde, 2.5 +/- 1.1; and sabinaketone, 0.036 +/- 0.023, where the error limits include the estimated overall uncertainties in the rate constants for the reference compounds. Upper limits to the O-3 reaction rate constants were also obtained, of <2 x 10(-20) cm(3) molecule(-1) s(-1) for pinonaldehyde and caronaldehyde, and < 5 x 10(-20) cm(3) molecule(-1) s(-1) for sabinaketone. These reaction rate constants are combined with estimated ambient tropospheric concentrations of OH radicals, NO3 radicals and O-3 to calculate tropospheric lifetimes and dominant transformation process(es) of these and other monoterpene reaction products.