Air quality 2016: Nitrogen dioxide still the top pollutant

Lower levels of particulate and ozone pollution

traffic jam in the cityClick to enlarge
Diesel-run vehicles are a major source of nitrogen dioxide.
Source: Kara /

The air in Germany’s cities continued to have excessive levels of nitrogen dioxide pollution in 2016. This is according to an evaluation of preliminary measurements made by the federal states and the German Environment Agency (UBA). The threshold value of 40 micrograms per cubic metre (µg/m³) on a yearly average was exceeded at about 57 per cent of all the measuring stations located near major thoroughfares. There has been only a slight decline in this trend since 2010. In contrast, there has been good progress made in particulate pollution: 2016 is the year with the lowest levels since 2000. Ozone concentrations were also rather low compared to the last 20 years. However, the limits for ozone and particulates which are recommended by the World Health Organization (WHO) continue to be exceeded. The WHO levels are much more restrictive than the limit values which apply in the EU.

“Nitrogen dioxide has been a threat to our health for decades”, said UBA’s President Maria Krautzberger. “It is old diesel-powered vehicles in particular which are to blame for this in cities. It is unacceptable on grounds of health that local authorities have no means of banning high-emissions diesel-run vehicles from crowded inner cities. Germany also has an obligation to the EU to take measures which ensure clean air in urban areas. The Blue NOx badge may be one crucial means of achieving the aim. Local authorities need uniform regulations throughout the country which establish who is awarded the Blue NOx badge and who is not. After all, it is their citizens’ health which is at stake.”

Particulate matter (PM10): With the exception of the start of the year, there were no weather conditions which especially favoured particulate matter pollution. Thus 2016 has become the year with the lowest measured levels of particulate matter pollution since 2000. The only case of exceedance of the EU limit value (PM10 daily mean value over 50 µg/m³ on more than 35 days in a year) was measured at the Stuttgart Neckartor station near traffic. The UBA is nevertheless concerned: The 20 µg/m3 annual mean guideline value recommended by the World Health Organization (WHO) was exceeded at nearly one quarter (24%) of all the measuring stations. Ms Krautzberger: "The federal government, Länder and local authorities must and can make greater efforts to reduce the health risk of exposure to particulate matter." Urgent action to reduce direct emissions of PM10 from private home fireplaces must be taken, also as concerns emissions of gaseous pollutant like ammonia from agriculture, which later form particulates.

Ozone: In contrast to the hot summer of 2015, the weather in summer 2016 was more changeable. There were no long periods of sunshine which could have favoured ozone formation but 21 per cent of all measuring stations nevertheless recorded exceedance of the target value (the 8-hour ozone level on a single day may not exceed 120 ug/m3 more than 25 days per calendar year, averaged over 3 years).

Climate change is increasing the risk of high ozone concentrations. The extreme heat in summer 2015 provided an example of the temperatures which can be expected more frequently in future. The UBA research project KLENOS has calculated that the number of days on which ozone levels exceed guideline values (days with a maximum 8-hour mean value of 120 µg/m3) will increase by 30 percent until 2050. In some regions, in particular in the south of Germany, that increase could even be greater. The problem can however be contained if emissions of ozone precursors are reduced – and they are mainly nitrous oxides from traffic and volatile organic compounds released from solvents in paints and varnishes. "We can only avoid high levels of ozone pollution in the face of continued climate change if we gain control of our nitrous oxide emissions", said Ms Krautzberger. "I am glad that all the EU Member States made a commitment in late 2016 to reduce their emisisons of particulates, ammonia, nitrous oxides and volatile hydrocarbon compounds by 2030. I hope this will not only contain the growing levels of ozone pollution but also reduce particulate pollution."

Umweltbundesamt Headquarters

Wörlitzer Platz 1
06844 Dessau-Roßlau

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 air quality  ozone concentration  nitrogen dioxide  particulate matter  PM10  diesel vehicle