The dust storms of Mexico City

Dust storms represent an important environmental problem affecting the comfort and health of one of the largest urban agglomerations in the tropical world. Data for dust events of varied intensities have been used in order to describe the seasonal and annual variation of dust storms in Mexico City. The maximum frequency of dust events occurs in March at the end of a three‐month period characterized by monthly rainfall amounts of about 13 mm. The frequency of intense (visibility less than 1 km) dust storms has markedly declined (to 0.6 year−1 for the period 1981–1987), apparently as a result of repasturing of Lake Texcoco's dry bed. However, dust activity of low magnitude as observed from Tacubaya has considerably increased in the Mexico Basin, apparently as a result of both accelerated deforestation and urbanization as well as a decrease in precipitation in recent years at the dust source. In spite of the low frequency of intense/moderate dust events, dustfall deposition rates observed near the dust sources are comparable to those measured elsewhere in arid environments.