Sulphur dioxide

Do sulphur dioxide concentrations meet EU air quality standards?
Drastic reductions in sulphur dioxide (SO2) levels in line with international trends were observed between 2000 and 2004, with a 36 per cent drop between 2003 and 2004 alone, due to the switch to low sulphur fuels. Reductions were observed in particular downwind of the Marsa power plant at Luqa, Fgura, Zejtun, Gudja, and Birzebbuga (of 51, 48, 44, 40, and 40 per cent respectively). In 2003 and 2004, no local council averages exceeded the WHO annual limit value for human protection of 50 µg/m3.

Although the overall SO2 burden has decreased substantially over the last few years, concentrations in particular sites such as Fgura/Hompesch Road are above the annual WHO standard. Real-time measurements of SO2 in Floriana showed that the hourly limit value of 350 µg/m3 (not to be exceeded for more than 24 times per year) was exceeded 74 times during the period from October 2003 to April 2004, before the switch to low-sulphur fuel was made.

This limit value was then exceed only seven times between May and end of 2004. Part of SO2 (like O3) being measured in Malta may also originate from overseas, and this is likely to be deposited over Malta due to the Islands' geographical situation and weather patterns.

The State of the Environment Report 2005 is a Mepa publication available on www.Mepa. org.mt.