Direct NO2 emissions: the state of knowlegde and consequences Raymond Gense Direct NO2 emissions from road transport 21-9-2018

Ambient air NO2 development De luchtkwaliteit is de afgelopen 30 jaar sterk verbeterd. De emissie zijn gedaald en de concentraties volgden ook. Maar alleen NO2 laat ondanks dalende emissies geen dalende concentraties zien. Voor fijn stof is dit discutabel. Zwarte rook lijkt eveneens tamelijk stabiel, terwijl PM10 de afgelopen jaren een daling te zien geeft. Probleem hierbij is dat niet zozeer gekeken moet worden naar de overschrijding van het jaargemiddelde, als wel naar de overschrijding van de dagnorm. In 2003 waren de PM10 concentraties hoog vanwege een lange droge zomer met veel oostenwind. In 2004 lagen de concentraties rond de grenswaarden, doordat 2004 een zeer nat jaar was en overwegend schone zuidwesten wind over ons land waaide. Direct NO2 emissions from road transport 21-9-2018

Direct NO2 emissions from road transport Detailed analyes Direct NO2 emissions from road transport 21-9-2018

NO2 sources versus ambient air sources NOx industry/energy roadtransport shipping others Direct NO2 emissions from road transport 21-9-2018

Explanations for stable NO2 levels: Changes in Ambient Ozone-NO-VOC chemistry Other than expected changes in Automotive exhaust gas composition Direct NO2 emissions from road transport 21-9-2018

The Automotive sector and NO2 NO2 emissions not regulated (only NOx) No standardised measurement procedure NO/NO2 equilibrium instable: Temperature Pressure Moisture Ozone UV Direct NO2 emissions from road transport 21-9-2018

NO/NO2 formation on the vehicle High temp NO (especially lean diesel) Fuel NO Low temperature NO2 (exhaust cool down) Catalyst(s) NO2 Direct NO2 emissions from road transport 21-9-2018

How to measure exhaust gas NO/NO2 ? Direct NO2 emissions from road transport 21-9-2018

Direct NO2 emissions from road transport So how to measure NO2? Fast Hot NO and NO2 simultaneously Without chemical interaction NO/NO2 Analyzer Direct NO2 emissions from road transport 21-9-2018

Comparison of (hot) measurements Direct NO2 emissions from road transport 21-9-2018

Direct NO2 emissions from road transport recommendations Measurement: Correct NO2 measurement in automotive exhaust gas seems to be possible No clear conclusions could (yet) be draw on the “best” measurement method Fast heated sampling and analyses seems to be adequate For low NO/NO2 ratios differential measurement seems not appropriate For measuring petrol and SCR-DeNOx engines CLD (conversion) is not suitable Direct NO2 emissions from road transport 21-9-2018

Relative NO2 fractions in passenger cars exhaust gas Petrol Diesel EC Calculation standard Direct NO2 emissions from road transport 21-9-2018

Real world source development Direct NO2 emissions from road transport 21-9-2018

Direct NO2 emissions : a problem? Direct NO2 emissions from road transport 21-9-2018

Effective source legislation! What needs to be done ? Effective source legislation! Early announcement of next steps: Low limit values NOx with low (<20%) NO2 Extremely low NOx limit value with current (40-70%) NO2 Establishment of an adequate test procedure: NO2 measurement “real world emissions” Direct NO2 emissions from road transport 21-9-2018

Direct NO2 emissions from road transport Thank you! Direct NO2 emissions from road transport 21-9-2018