Twenty years of ambient observations of nitrogen oxides and specified hydrocarbons in air masses dominated by traffic emissions in Germany

• DOI: 10.1039/c5fd00180c
• Publication Date: 2015-12-09T18:22:41Z
• Authors: Christian Ehlers; Dieter Klemp; Franz Rohrer; Djuro Mihelcic; Robert Wegener; Astrid Kiendler-S...; Andreas Wahner
• Keywords: Nitrogen oxides

The analysis of the individual composition hydrocarbon (VOC) mixtures enables us to transform observed VOC-concentrations into their respective total VOC-reactivity versus OH radicals (RVOC = Σ(kOH+VOCi × [VOCi])). This is particularly useful because local ozone production essentially depends on this single parameter rather than details underlying mixture (Klemp et al., Schriften des Forschungszentrums Jülich, Energy & Environment, 2012, 21). VOC also pin down major emission source hydrocarbons in urban areas be petrol cars with temporarily reduced catalyst efficiency (the so-called cold-start situation) whereas nitrogen oxides (NOx NO + NO2) expected nowadays dominated by diesel cars. observations vicinity main roads German cities show a decrease ratio reactivities and NO2 (RVOC/RNO2) factor 7.5 over time period 1994-2014. larger 2.9 taking estimated trends NOx traffic emissions Germany (Umweltbundesamt Deutschland, National Trend Tables for Atmospheric Emission Reporting, 2015), during period. reduction RVOC/RNO2 leads drastic driven hydrocarbons. reveals that overall benefits from low road which consequence eventual absence catalytic converters oxide removal up now.