Temporal variations in atmospheric CO₂ concentrations in Kuwait City, Kuwait with comparisons to Phoenix, Arizona, USA

Hourly atmospheric carbon dioxide (CO₂) concentration measurements are available from 1996 to present for a suburban site within the growing metropolitan area of Kuwait City. Analyses of this record reveal (a) an annual cycle with highest values in February and lowest values in September reflecting the growth and decay of vegetation in the Northern Hemisphere as well as fluctuations in motor traffic, (b) a weekly cycle with highest values during the weekdays and lowest values during weekends, and (c) a diurnal cycle with highest values after sunset when the local atmosphere becomes more stable following vehicular emission of CO₂ throughout the day and lowest values in late afternoon following several hours of relatively unstable conditions. During the daytime, CO₂ concentrations are related to wind direction, with westerly winds (coming from the desert) promoting lowest CO₂ concentrations. At night, lowest CO₂ levels are associated with higher wind speeds and winds from the north. The findings from the Kuwait City area, particularly when contrasted with the situation in Phoenix, further our understanding of the dynamics of CO₂ levels in urban environments.