Nitrogen dioxide concentrations

Do nitrogen dioxide concentrations in Malta meet EU air quality standards?

Nitrogen dioxide (NO2) is a toxic gas at short-term concentrations exceeding 200µg/m3, and long-term exposure at lower concentrations. It forms acids when it interacts with water vapour and forms nitrates and other harmful compounds when it interacts with other particles.

NO2 is a direct result of fossil fuel burning (such as in power generation and vehicle engines), as well as of natural sources such as lightning. Between 2008 and 2009 the annual average national NO2 concentration decreased slightly from 29µg/m3 to 28.2µg/m3, remaining well below the 40µg/m3 EU and WHO limit value. In 2009, annual average values exceeded annual EU standards in 5 localities: Floriana (70.6µg/m3); Ħamrun (50.3µg/m3); Fgura (49.3µg/m3); Birkirkara (44.3µg/m3); and Sliema (42.2µg/m3).

In addition, 22 individual sites registered NO2 levels higher than the EU and WHO limit, with St Anne’s Street, Floriana recording the highest value (98.1µg/m3). In 2009, the hourly limit value (not to be exceeded for more than 18 hours per year) was not exceeded in any of the monitoring stations.