A report on the nature, distribution and likely source of coarse black dust particles in Malta, has concluded that the Marsa Power Station is the likely source of the problem, Mepa said today.

The report, which was drawn up by Professor Alfred J. Vella and a team working at the University of Malta, was commissioned by the Malta Environment and Planning Authority (MEPA) in August 2009, following an inconclusive investigation it had carried out a year earlier.

Long-standing complaints about black dust have originated mainly from Fgura and other towns in the southern area of the Grand Harbour such as Paola and Tarxien, with a spate of complaints received in the summer months of 2009.

Prof Vella's report is based on a study, which was carried out between August 2009 and November 2010 and its conclusions complement the conclusions reached by another study conducted by the same author in 1995 on "limestone surfaces in built-up environments as indicators of atmospheric pollution" and published in an international scientific journal.

"Given the large size of the black dust particles, the report concludes that their source is in close proximity to the areas which are highly affected by its deposition. The morphology and chemical composition of the analysed dust infer that combustion of fuel oil is the likeliest source of these soiling episodes and this, together with Malta's prevailing wind direction, all point to the Marsa power station as the constant main source of coarse black dust particles, although other sources cannot be excluded," Mepa said.

The Authority said the report anticipates that once the Marsa power station is decommissioned, deposition of the coarse black particles will very likely decrease considerably.

"However, the fine black dusts which motor traffic produces constantly and continuously will continue to affect any area where traffic flows are high."

In 2009 the Authority established emission limit values for dust, sulphur dioxide and nitrogen oxides at the Marsa power station through the issuing of an Integrated Pollution Prevention and Control (IPPC) permit, and a derogation of 20,000 hours was applied, following which the Marsa power station will be decommissioned.

The full report and executive summary can viewed on the Authority's website http://www.mepa.org.mt/air-publications