In addition to the foreign foci, there are areas inside the country that have either formed new dust foci in recent years or were from the past and their extent has increased. Among these areas, parts of southern Tehran, south of Alborz province - which in the past were plains, riverbeds, seasonal lakes and seasonal reservoirs - and Gavkhoni wetland of Isfahan province can be mentioned because they have become dry and prone to dust. Among other areas that have become dust centers, Qom province, the Qom salt lake and its surroundings can be mentioned, as well as the Urmia lake, which due to strong winds and due to the dryness of the lake and the reduction of its size, some areas of its bed which were under water in the past are subject to wind erosion.