UFP and BC at a mid-sized city in Po valley, Italy: Size-resolved partitioning between primary and newly formed particles
| Autor: | Stefano Cernuschi, S. Ozgen, Gianluigi Valli, Giovanni Lonati, Fenjuan Wang, Giovanna Ripamonti, Roberta Vecchi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Pollution
Atmospheric Science 010504 meteorology & atmospheric sciences Particle number Meteorology media_common.quotation_subject 010501 environmental sciences Particulates Atmospheric sciences 01 natural sciences Black carbon Cluster analysis Po valley Ultrafine particles 2300 Atmosphere Ultrafine particle Cluster (physics) Particle Environmental science Air quality index 0105 earth and related environmental sciences General Environmental Science media_common |
| Popis: | In Po valley (Northern Italy) concentrations of particulate matter (PM) often exceed air quality standards, and road traffic is reported as one of the main sources of pollution. This study investigates the size resolved particle number concentration and size distribution at one rural station, one urban station and one traffic station. The measured size-resolved particle number concentration has been reduced by means of cluster analysis to four particle size fractions (cluster 1: 7–29 nm, cluster 2: 29–95 nm, cluster 3: 95–264 nm, and cluster 4: 264–10,000 nm) based on their behavior in atmosphere according to common time patterns. The primary emissions from traffic are evaluated based on black carbon (BC) and size-resolved particle number concentration data, considering separately single size intervals and providing cluster-resolved information on primary and newly formed particle concentration. Particles directly emitted by vehicle exhaust exhibit similar numbers for the clusters 1 to 3 while newly formed particles mainly occurs in cluster 1. Furthermore, diurnal variation of directly emitted particles is found to closely follow the BC levels, while the trend of newly formed particles varies according to air temperature, solar radiation and particle pollution levels. The results release that in Po valley the variations of particle number levels do not always reflect the variation of road traffic emissions in urban areas as the large availability of anthropogenic precursors can favor summertime nucleation events with region-wide extension. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|