The European Environmental Agency sets pollution exposure standards in its EU’s air quality directives (2008/50/EC, 2004/107/EC). These standards should not be exceeded in a given period of time. If they are nevertheless exceeded, then European governments have to find ways to act and reduce the pollutants. What is very surprising is that the EU target values are much lower than the World Health Organization guidelines. What is going on?

If we compare the EU target levels for pollution exposure of the urban population (see the Figure 1), we see that only a smaller proportion of the European urban population seems to be subjected to air pollutant concentrations above the EU target levels. However, if we instead rely upon the WHO guidelines for air pollutant concentrations, we immediately observe that these are much stricter. In fact, if we rely upon the EU target values, then only 6-8% of the urban population in Europe is exposed to PM2.5 levels that exceed the regulatory threshold, while if we were to apply the WHO guidelines, then this number would shoot up to 74-81% of the EU urban population. More worrying is e.g. Ozone (O3): According to the EU standards, at maximum 1/3 of the EU urban population is exposed to O3 levels above the regulator threshold, while according to the WHO nearly everyone who lives in urban centres in Europe is exposed to levels above the WHO guidelines.

Figure 1
Figure 1

So we ask ourselves how these EU regulations differ from the WHO guidelines. This is shown in Figure 2 below. For most of the pollutants we observe that the WHO guidelines are stricter than those of the EU standards, sometimes double as strict as the EU standard. Why is that the case?

Figure 2

This is described in the Directive 2008/50/EC. Countries are subject to a national exposure reduction target which, at least for PM2.5, should converge to the WHO guidelines until 2020. For now it seems that the EU applies more closely the WHO interim targets, which are a roadmap guiding highly polluted countries towards achieving the ultimate goal, which are the WHO guidelines. There are three interim targets, IT-1 to IT-3, where IT-1 is the weakest interim target, IT-3 the strongest, but still weaker than the WHO guidelines. Comparing the EU standards to the WHO interim targets, we find that the EU standards are set somewhere between IT-2 and IT-3. If the WHO guidelines are the ultimate targets, then we see that this would mean that a large share of the EU urban population is subjected to severe health risks from a variety of pollutants. Thus, the EU still has a long way to go if it wants to prevent its urban population from being harmed by the main pollutants.

So which ones are the `right’ ones? Or the better ones? Let us imagine that the ultimate goal of the European Union is to set its pollution exceedance standards over time and aims at adhering to the WHO guidelines. This is not entirely clear from the EU Directive 2008/50/EC, but at least it is likely that this may be the objective. Then the question is as to why the EU does not immediately say that its objective is that all member states will ultimately adhere to the WHO guidelines. By setting EU wide standards that apply equally to highly polluted Eastern European countries as well as less polluted Northern European or Central European countries, the EU risks that those less polluted countries do not provide the same level of effort as is demanded from the highly polluted regions as the less polluted regions already adhere to the softer EU standards. If the ultimate goal is to adhere to the WHO guidelines, then the EU standard should be the WHO guideline together with a roadmap of how this can be achieved.

An additional point is that even the stricter WHO guidelines seem outdated. A recent publication from an WHO Expert Consultation in 2015 finds that the more recent evidence suggests that the WHO guidelines should be made stricter for nearly all pollutants. These should be published in the near future in the updated WHO Global Air Quality Guidelines. Let’s hope that the EU pollution exceedance standards will target these new guidelines.