The UV decadic molar absorptivities of nitrite ion in water were deter
mined between 290 and 400 nm in 2-nm increments. The measured maximum
absorptivity of 22.93 M cm(-1) at 354 nm is in agreement with previous
results. Using absorptivities obtained in this wavelength range, we c
alculated the first-order rate constant for the formation of OH radica
ls by the photolysis of aqueous nitrite in summer noon sunlight at 40
degrees N. The resulted rate constants, 5.2 x 10(-5) s(-1) for surface
water and 1.04 x 10(-4) s(-1) for cloud and rain water droplets, are
twice the previously reported values. The environmental significance o
f these results is discussed briefly. (C) 1997 Elsevier Science Ltd.