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The Urban CO2 Dome of Krakow, Poland
Zimnoch, M., Florkowski, T., Necki, J.M. and Neubert, R.E.M. 2004. Diurnal variability of 13C and 18O of atmospheric CO2 in the urban atmosphere of Krakow, Poland. Isotopes in Environmental and Health Studies 40: 129-143.

Krakow, Poland is a large urban center with more than 800,000 inhabitants, a large steel factory, and numerous other industries. It sits in a river valley surrounded by hills, where it experiences frequent night-time inversions that are especially strong in winter and that trap local CO2 emissions near the surface of the earth. House heating via coal-burning single-room ovens in numerous houses in the center of the city also results in strong CO2 emissions in winter, as does heavy vehicular traffic in all seasons.

What was done
At four different times of the year, the authors made diurnal measurements of the concentration and isotopic composition (13C, 18O) of atmospheric CO2 at a height of 20 meters above ground level at a location in the western part of the city that borders recreation and sports grounds and is some distance away from direct low-emission CO2 sources and strong car traffic.

What was learned
"During winter," in the words of Zimnoch et al., "the local CO2 contribution is made up almost exclusively from anthropogenic emissions," which produce nighttime atmospheric CO2 concentrations at 20 meters above ground level that are sometimes as high as 440 ppm, although they say that "the calculated mean contribution of anthropogenic CO2 to the city atmosphere during winter is about 30 ppm."

During the daytime in summer, they report that "the dominant source of CO2 is the local biosphere," and that "when the lower atmosphere was intensely mixed, the recorded CO2 concentration dropped to values close to those observed at 'clean' continental stations (354 ppm)." On some summer evenings, however, CO2 emissions from respiration and biomass decomposition would cause the air's CO2 concentration to rise as much as anthropogenic CO2 emissions would cause it to rise in the winter.

What it means
Zimnoch et al.'s data suggest that the urban CO2 dome of Krakow is much like that of Phoenix, Arizona, as well as the CO2 domes of some of the Other Cities of the world where this phenomenon has been investigated.

Reviewed 18 August 2004