Apportionment of Motor Vehicle Emissions from Fast Changes in Number Concentration and Chemical Composition of Ultrafine Particles Near a Roadway Intersection
| Autor: | Christopher A. Zordan, M. Ross Pennington, Murray V. Johnston, Joseph P. Klems, Lauren McFadden |
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| Rok vydání: | 2011 |
| Předmět: |
Particle number
Air pollution Mineralogy Exhaust gas General Chemistry Models Theoretical Delaware medicine.disease_cause Mass Spectrometry Aerosol law.invention Ignition system Diesel fuel law Ultrafine particle medicine Environmental Chemistry Environmental science Particulate Matter Seasons Particle size Particle Size Vehicle Emissions |
| Zdroj: | Environmental Science & Technology. 45:5637-5643 |
| ISSN: | 1520-5851 0013-936X |
| DOI: | 10.1021/es104228q |
| Popis: | High frequency spikes in ultrafine number concentration near a roadway intersection arise from motor vehicles that accelerate after a red light turns green. The present work describes a method to determine the contribution of motor vehicles to the total ambient ultrafine particle mass by correlating these number concentration spikes with fast changes in ultrafine particle chemical composition measured with the nano aerosol mass spectrometer, NAMS. Measurements were performed at an urban air quality monitoring site in Wilmington, Delaware during the summer and winter of 2009. Motor vehicles were found to contribute 48% of the ultrafine particle mass in the winter measurement period, but only 16% of the ultrafine particle mass in the summer period. Chemical composition profiles and contributions to the ultrafine particle mass of spark vs diesel vehicles were estimated by correlating still camera images, chemical composition and spike contribution at each time interval.. The spark and diesel contributions were roughly equal, but the uncertainty in the split was large. The distribution of emissions from individual vehicles was determined by correlating camera images with the spike contribution to particle number concentration at each time interval. A small percentage of motor vehicles were found to emit a disproportionally large concentration of ultrafine particles, and these high emitters included both spark ignition and diesel vehicles. |
| Databáze: | OpenAIRE |
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