The Saharan dust clouds are back in Greece as of Wednesday, with the phenomenon expected to unfold and reach its peak over the rest of the week, the Athens National Observatory meteorological service said.
Dust concentrations are predicted to reach their maximum levels in Heraklion, Crete on Thursday and will be most intense in the Athens area over Friday and Saturday.
The models forecast that dust concentrations in Athens will reach a maximum of 130 microgrammes per cubic metre of air by Saturday afternoon before gradually dropping off.
The maximum concentration in Heraklion is forecast to reach 240 microgrammes per cubic metre of air on Thursday night, with the densest concentrations at a height of 1,500 to 3,000 metres above ground level.
The phenomenon is caused by low pressure weather systems in the Western Mediterranean that are driving large quantities of African dust toward Greece.
According to weather scientists, the intensity of the problem will not be as severe as in March but people are advised to avoid strenuous outdoor activities and sports in more southern parts of the country.