*2.1. Study Area*

Havana is the province with the smallest area in Cuba, occupying 727.4 km2. It is situated on the northern coast, surrounding the Havana Bay, where the main port of the country is located. The province has a population of 2.13 million inhabitants and a population density of 3000 inhabitants/km2. One hundred percent of the province is urbanized. The climate is tropical with two distinct seasons: a wetter season (May–October) and a drier season (November–April). The monthly average temperature ranges between 22 and 27 ◦C, with an annual average of 25.7 ◦C. The annual average relative humidity is 80%, and the annual rainfall is 1240 mm. The geology of the area is mainly sedimentary limestone and ultramafic rocks, sometimes serpentinized.

Several industries are located in this province, which could well be a source of PTEs, including an oil refinery, metal processing industries, and power plants. The dense traffic of motor vehicles, some of them very old, could also contribute to the emissions.

The province consists of 15 districts, distributed in three areas: central, intermediate, and peripheral. Soils were selected for study in 6 of the 15 districts, 5 in the central area, the most densely populated, and 1 (Playa) in the intermediate area. The latter district has experienced a rapid socio-economic and touristic development in recent decades.
