Enemalta decided to use heavy fuel oil at the Delimara power station extension during the tendering process for the power generating plant. The installed equipment, however, can function through the use of either HFO or gas oil. The former is a heavy polluter, the latter polluting substantially less.
Pollution in the Marsaxlokk Bay area affects Marsaxlokk, Birżebbuġa and Żejtun. It is made up of accumulated emissions from Marsa and Delimara power stations, land transport and emissions from air traffic in the flight path over Birżebbuġa prior to landing.
The Malta Environment and Planning Authority has concluded public consultation on Enemalta’s integrated pollution prevention and control application to operate the Delimara power station extension. During this consultation, Mepa released an air dispersion modelling report it commissioned. Authored by Maltese consultants Ecoserve Ltd with their Austrian partners, the report is dated August 2011.
The report applies a range of numerical simulation models for air quality impact assessment to the Delimara power station and its extension in a domain around the plant. The Ecoserve report, utilising emission data supplied by Enemalta, concludes that present accumulated emissions in the Marsaxlokk Bay area are well within the limits of the EU Clean Air Directive. It then goes on to simulate the emissions when the Delimara extension starts functioning and the Marsa power station is switched off.
Now this conclusion contrasts with other information contained in the study. Limiting myself to particulate matter, data collected over a four-week period by Mepa and reproduced in the Ecoserve study shows that in the period under the spotlight particulate matter present in the air at Marsaxlokk and Birżebbuġa was well in excess of permissible limits in terms of the EU Air Quality Directive.
Average PM2.5 daily readings measured 52.50 μg/m3 at Marsaxlokk and 34.7 μg/m3 at Birżebbuġa whereas maximum readings were 149 μg/m3 at Marsaxlokk and 61 μg/m3 at Birżebbuġa. This contrasts with the target value of 25 μg/m3 for PM2.5, which is mandatory in terms of the EU Air Quality Directive. This means an average reading of 210 per cent of the EU limits for Marsaxlokk and 139 per cent for Birżebbuġa.
On the other hand, average PM10 readings measured 54.10 μg/m3 for Marsaxlokk and 70 μg/m3 for Birżebbuġa while maximum readings were 154 μg/m3 at Marsaxlokk and 250 μg/m3 at Birżebbuġa. This contrasts with the limit value of 50 μg/m3 (daily average) that is mandatory in terms of the EU Air Quality Directive. This means an average reading of eight per cent above the EU limits for Marsaxlokk and 40 per cent above EU limits for Birżebbuġa.
In contrast, the simulation exercise “assuming the worst case scenario meteorology for 2010” concludes an annual average of 12.1 μg/m3 of PM10 with just four cases when the EU limit is exceeded! As the EU directive permits exceedances on not more than 35 occasions, the simulation exercise concludes that all would be fine at Marsaxlokk Bay.
(PM10 refers to particulate matter up to 10 microns in diameter whereas PM2.5 refers to particulate matter up to 2.5 microns in diameter.)
The Ecoserve study does not explain how this discrepancy between the conclusions of the simulation exercise and the Mepa actual readings in Marsaxlokk and Birżebbuġa is to be interpreted. Both Mepa and its contractor, Ecoserve Ltd, have a lot of explaining to do.
Mepa also has a duty to explain why the request by local councils for a long-term air monitoring exercise at Marsaxlokk and Birżebbuġa was not acted upon. Having data covering a longer time frame would lead to more robust conclusions relative to air quality at Marsaxlokk Bay. As things stand, having a contrast between simulated and real-life data, I would not hesitate one second to give more weight to the data actually measured. As to the projections into the future they simply cannot be relied upon.
Particulate matter present in the air gives rise to various issues of health. These fine particles originate primarily through the combustion of fuels, their chemical composition depending on the fuel from which they originate. The coarser particles when inhaled by humans lodge in the upper respiratory tract while the finer ones deposit themselves inside the lungs and are absorbed into the bloodstream causing a multitude of health problems.
As indicated by various studies, the excessive presence of particulate matter in the air is one of the causes of various respiratory ailments notably asthma, the incidence of which, according to medical general practitioners in the area, has been rising considerably in the Marsaxlokk Bay area over the past years.
In view of the above, it is clear that the choice of fuel on which the Delimara power station extension is run will contribute significantly to air quality in the Marsaxlokk Bay area. Use of HFO will take our breath away as it would increase the emission of particulate matter. Using gas oil, on the other hand, would ensure lower emissions and give the opportunity of breathing cleaner air to the community residing around the Marsaxlokk Bay.
An architect and civil engineer, the author is the spokesman on sustainable development and local government of Alternattiva Demokratika – the Green party in Malta
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