Abstract
n a novel approach, aspects of ambient air quality, atmospheric processes, road traffic and air quality guidelines have been combined to specify emission levels of vehicles that “do not affect” air quality at kerbside. Zero impact air quality targets were specified to 1.2 µg/m³ for NO2, 0.5 µg/m³ for PM2.5 and 650 #/cm³ for particle number (PN 20-800 nm).
The inferred zero impact vehicle exhaust emissions rely on assumptions such as an appropriately selected monitored worst case air quality situation, and the assumption of a linear relationship between emissions and corresponding contributions to ambient concentrations, i.e. the reduction rates were transferred to zero-impact vehicle (ZIV) emissions. Hence, model calculations were carried out to validate the emission factors of a hypothetical 100% ZIV fleet to fulfil these zero impact air quality targets. A Lagrangian particle model was used to simulate the dispersion of NOx, PM2.5 and PN in selected urban case studies and to see if the zero impact air quality targets can be generally fulfilled. The classical scenario evaluation approach was used, i.e. a base case simulated and validated versus air quality monitoring. For PM2.5 and NO2 the base case validation was straightforward and it could be demonstrated that the Scenario 100% ZIV fleet fulfills above mentioned air quality targets at kerbside.
PN and NOx were monitored over 7 hours at 1 m, 3 m and 5 m kerbside distance at an arterial road in a street canyon in Graz/Austria. Detailed dispersion computations were carried out for NOx and PN. A good match was found for NOx dispersion. Regression analysis for PN resulted in an R² of 0.85 but a slope of 3.9. A slope of 3.8 was found for a detailed 2 ½ month PN case study in Augsburg/Germany. The simulated dispersion of exhaust PN relates to solid particle number (SPN). Within the standardized, vehicle exhaust emission measurements volatiles are removed or supressed. In the two case studies total PN was monitored. The slope may give an indication about the number of
volatile particles. However, a correction for volatiles cannot be justified in the evaluation of the ZIV scenario.
The inferred zero impact vehicle exhaust emissions rely on assumptions such as an appropriately selected monitored worst case air quality situation, and the assumption of a linear relationship between emissions and corresponding contributions to ambient concentrations, i.e. the reduction rates were transferred to zero-impact vehicle (ZIV) emissions. Hence, model calculations were carried out to validate the emission factors of a hypothetical 100% ZIV fleet to fulfil these zero impact air quality targets. A Lagrangian particle model was used to simulate the dispersion of NOx, PM2.5 and PN in selected urban case studies and to see if the zero impact air quality targets can be generally fulfilled. The classical scenario evaluation approach was used, i.e. a base case simulated and validated versus air quality monitoring. For PM2.5 and NO2 the base case validation was straightforward and it could be demonstrated that the Scenario 100% ZIV fleet fulfills above mentioned air quality targets at kerbside.
PN and NOx were monitored over 7 hours at 1 m, 3 m and 5 m kerbside distance at an arterial road in a street canyon in Graz/Austria. Detailed dispersion computations were carried out for NOx and PN. A good match was found for NOx dispersion. Regression analysis for PN resulted in an R² of 0.85 but a slope of 3.9. A slope of 3.8 was found for a detailed 2 ½ month PN case study in Augsburg/Germany. The simulated dispersion of exhaust PN relates to solid particle number (SPN). Within the standardized, vehicle exhaust emission measurements volatiles are removed or supressed. In the two case studies total PN was monitored. The slope may give an indication about the number of
volatile particles. However, a correction for volatiles cannot be justified in the evaluation of the ZIV scenario.
| Original language | English |
|---|---|
| Number of pages | 5 |
| Publication status | Accepted/In press - 11 Sept 2022 |
| Event | 21st International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes: HARMO 2021 - Aveiro, Portugal Duration: 27 Sept 2022 → 30 Sept 2022 |
Conference
| Conference | 21st International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes |
|---|---|
| Abbreviated title | HARMO21 |
| Country/Territory | Portugal |
| City | Aveiro |
| Period | 27/09/22 → 30/09/22 |
