Shipping’s contribution to the overall pollution load is increasing, while emissions from land-based sources are decreasing. Photo: Flickr.com/ecstaticist/CC BY-NC-SA
Sulphur emissions show the biggest reductions, while there is much less improvement for ammonia and particulate matter. Cuts in land-based emissions are countered by rising emissions from international shipping.
Since 1980, total European emissions of sulphur dioxide (SO2) – the most significant acidifying pollutant and an important precursor to health-damaging secondary fine particles (PM2.5) – from land-based emission sources have fallen by 84 per cent, from around 53 million tonnes in 1980 to 8.2 million tonnes in 2011.
Emissions of nitrogen oxides (NOx), non-methane volatile organic compounds (VOCs), and ammonia have also gone down, although to a lesser extent. VOCs have more than halved (-58 per cent) since 1980, while NOx and ammonia emissions have dropped by 46 and 35 per cent, respectively.
Since the late 1990s, emissions of primary fine particles (PM2.5) have been attracting increasing attention, mainly because of their negative impacts on health. However, these emissions are not as well documented as those of other air pollutants, and many countries lack emissions data for the 1990s. Between 2000 and 2011 it is estimated that emissions of PM2.5 from land-based sources have fallen by 35 per cent, from 2.8 to 1.8 million tonnes.
Looking specifically at the 28 member states of the European Union, between 1980 and 2011 the emissions of SO2 came down by 88 per cent, while those of NOx, VOCs and ammonia fell respectively by 50, 61 and 30 per cent. The emissions of PM2.5 were only reduced by 24 per cent between 2000 and 2011.
Emissions of NOx and SO2 from international shipping in European waters show a steady increase. Since 1980, ship emissions of SO2 have gone up from 1.7 to 2.4 million tonnes (a 36 per cent increase), and those of NOx from 2.4 to 4.1 million tonnes (67 per cent).
The data in Table 1 is taken from figures reported by countries themselves to the Convention on Long-range Transboundary Air Pollution, and was compiled by the European Monitoring and Evaluation Programme (EMEP). The Convention’s EMEP keeps track of the ways in which emissions from one country affect the environment in others. The EMEP report also provides an overview of calculations for source-receptor relationships (including transboundary movements between countries), covering acidifying, eutrophying, photo-oxidant, and particle pollution.
Table 1: European emissions of sulphur dioxide, nitrogen oxides (as NO2), VOCs, ammonia, and PM2.5 (kilotonnes). Data for 2000 and 2011 is from the 2013 EMEP report, while data for 1980 and 1990 is from earlier EMEP reports. Russia in the table refers only to the western parts of the Russian Federation.
For most European countries the biggest share of depositions of sulphur and nitrogen emanate from outside their own territory, and an increasing share of the depositions originate from international shipping.
Since land-based emissions are gradually coming down, while those from international shipping show a continuous increase, shipping’s contribution to pollutant depositions and concentrations is getting bigger and bigger. For 2011 it was estimated that ship emissions were responsible for ten per cent or more of the total depositions of both sulphur and oxidised nitrogen compounds in many countries (see Table 2). In the coastal areas of these countries, shipping’s contribution to the overall pollution load is even higher. Countries that are particularly exposed to air pollution from shipping include Ireland, Denmark, Sweden, Norway, the Netherlands, Portugal and the United Kingdom.
Table 2: European countries where the proportion of air pollutant depositions of sulphur and oxidised nitrogen from ships is the most marked.
EMEP has also studied the contribution of air pollutants to the input of nitrogen to the Baltic Sea. It is estimated that atmospheric deposition typically accounts for about one quarter to one third of the total nitrogen load to this sea. The three main contributors to the deposition of oxidised nitrogen compounds are Germany, Poland and ship traffic in the Baltic Sea, accounting together for almost 40 per cent of the input.