Table 1. Comparison of pesticides reactivity towards OH radicals in gas phase and in partficle phase (rate constants and half-lives) and partitioning of pesticides in particle phase with the effective rate constants.

Pesticide	estimated in gas-phasea (cm3 molecule−1 s−1)	Estimated half-lives in gas phaseb (days)	in particle phases (cm3 molecule−1 s−1)	Partitioning in particle phasecΦpesticide	in gas and particle phases (cm3 molecule−1 s−1)	Atmospheric half-lives in gas and particle phasesb (days)
Pendimethalin	3.0 · 10−11	0.4	(4.3 ± 2.2) · 10−13	0.01	3.0 · 10−11	0.4
Cyprodinil	2.0 · 10−10	0.1	(9.7 ± 2.9) · 10−13	0.07	1.9 · 10−10	0.1
Tetraconazole	1.1 · 10−11	1.0	<<(4.3 ± 2.2) · 10−13	0.38	<<7.0 · 10−12	>>1.5
Oxadiazon	2.4 · 10−11	0.5	<<(4.3 ± 2.2) · 10−13	0.62	<<9.4 · 10−12	>>1.1
Fipronil	9.6 · 10−11	0.1	<<(4.3 ± 2.2) · 10−13	0.84	<<1.6 · 10−11	>>0.7
Deltamethrin	2.3 · 10−11	0.5	(6.9 ± 2.8) · 10−13	0.91	2.7 · 10−12	4.0
Permethrin	2.3 · 10−11	0.5	(5.5 ± 2.2) · 10−13	0.97	1.2 · 10−12	8.9
Difenoconazole	2.2 · 10−11	0.5	<<(4.3 ± 2.2) · 10−13	0.99	<<6.5 · 10−13	>>16.5

^aEstimated rate constants by modeling using AOPWIN program.

^bHalf-lives for an average concentration [OH_(g)] = 1.5 · 10⁶ cm⁻³ and for an exposure of 12 h by day.

^cPartitioning in the particle phase estimated by AEROWIN software using the Junge-Pankow adsorption mode.