Lusaka, Zambia, during SAFARI-2000: Convergence of local and imported ozone pollution

Date

2002-10-25

Department

Program

Citation of Original Publication

Thompson, Anne M., Jacquelyn C. Witte, M. Tal Freiman, N. Agnes Phahlane, and Gert J. R. Coetzee. “Lusaka, Zambia, during SAFARI-2000: Convergence of Local and Imported Ozone Pollution.” Geophysical Research Letters 29, no. 20 (2002): 37-1-37–4. https://doi.org/10.1029/2002GL015399.

Rights

This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain

Subjects

Abstract

In August and September, throughout south central Africa, seasonal clearing of dry vegetation and other fire-related activities lead to intense smoke haze and ozone formation. The first ozone soundings in the heart of the southern African burning region were taken at Lusaka, Zambia (15.5S, 28E) in early September 2000. Maximum surface ozone was over 90 ppbv and column tropospheric ozone exceeded 50 DU. These values are higher than concurrent measurements over Nairobi (1S, 38E) and Irene (25S, 28E, near Pretoria). At least 30% of Lusaka surface ozone appears to be from local sources. A layer at 800–500 hPa has ozone >120 ppbv and originates from trans-boundary recirculation. Starting out over Zambia, Angola, and Namibia, ozone-rich air travels east to the Indian Ocean, before heading back toward Mozambique, Zimbabwe and Zambia. Thus, Lusaka collects local and imported pollution, consistent with its location within the southern African gyre.