At a glance
- The exposure of the population to particulate matter in areas not affected by intensive traffic has substantially decreased since 2007.
- Particulate matter concentrations in ambient air are considerably affected by weather conditions which may vary substantially within the year and from one year to another.
- The Federal Government’s aim is that the guideline value of the World Health Organisation (WHO) should not be exceeded by 2030.
Particulate matter in ambient air is harmful to human health: the particles enter the human body through the respiratory system. Depending on the size of the particles, they can penetrate deeply into the respiratory system and even enter the blood stream when penetrating the pulmonary tissue. There is clear evidence that particulate matter can trigger various diseases (cf. ‘Health risks due to particulate matter’ indicator).
Particulate matter is predominantly man made, resulting from combustion processes. A considerable share of particulate matter is ‘secondary’ particulates which are formed in the atmosphere from precursor substances, including nitrogen oxides from combustion processes and ammonia from agriculture.
The indicator focuses on the particulate matter exposure levels from rural and urban background areas, but does not take into account severely polluted areas such as roads with high traffic volumes or areas that are close to large industrial plants. The guideline value of the World Health Organisation (WHO) for health protection is used as the standard of evaluation for the indicator. The German Environment Agency considers the limit set by the European Ambient Air Quality Directive (EU DIR 2008/50/EC) too high to be protective for human health.
Assessing the development
The number of people in Germany that are exposed to particulate matter concentrations above the WHO long-term exposure guideline value has substantially decreased since 2007. This is mainly because the measures that were introduced to reduce emissions are becoming effective now, particularly in the transport sector. Other developments including the growing number of households using wood-fired heating are counteracting this progress. In addition, particulate matter concentrations in ambient air are considerable affected by weather conditions which might vary substantially from one year to another.
The EU Air Quality Directive defines a mean annual limit value of 40 µg/m³ for PM10 to protect human health. In Germany, this annual limit value has not been exceeded in rural and urban background areas in recent years. However, the WHO recommends a more stringent guideline value of 20 µg/m³ (WHO 2006). The German Sustainable Development Strategy states that by 2030, the stricter WHO guideline value should not be exceeded in Germany any more (BReg 2016).
Further stimuli for reductions in particulate matter pollution are primarily expected from binding international air pollution agreements (cf. ‘Emission of air pollutants’ indicator) and from clean air plans introduced by cities and local authorities.
The indicator is calculated by combining modelled data from the REM-CALGRID chemical transport model, PM10 measurement data provided by the Federal States of Germany and the German Environment Agency and additional interpolation procedures resulting in PM10 exposure maps for Germany. The areal PM10-concentrations are combined with population density maps to introduce a population weighting scheme. The data used in the calculation only represent rural and urban PM10 background concentration levels in Germany and neglects urban traffic hot spots. For more methodical details, see Kallweit et al. 2013 (in German, abstract in English).