The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland
Three years of aerosol particle number concentrations (PNCs), size distributions and vertical particle fluxes measured at the semi-urban SMEAR III station in Helsinki, Finland, were studied. The purpose is to study the local emission sources and their effect on particle concentrations and size distr...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Stockholm University Press
2013-06-01
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| Series: | Tellus: Series B, Chemical and Physical Meteorology |
| Subjects: | |
| Online Access: | http://www.tellusb.net/index.php/tellusb/article/download/19786/pdf_1 |
| _version_ | 1818247049980674048 |
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| author | Giovanna Ripamonti Leena Järvi Bjarke Mølgaard Tareq Hussein Annika Nordbo Kaarle Hämeri |
| author_facet | Giovanna Ripamonti Leena Järvi Bjarke Mølgaard Tareq Hussein Annika Nordbo Kaarle Hämeri |
| author_sort | Giovanna Ripamonti |
| collection | DOAJ |
| description | Three years of aerosol particle number concentrations (PNCs), size distributions and vertical particle fluxes measured at the semi-urban SMEAR III station in Helsinki, Finland, were studied. The purpose is to study the local emission sources and their effect on particle concentrations and size distributions. By means of cluster analysis, six representative size distributions were identified. Their occurrence together with particle concentrations and fluxes were found to vary significantly with wind direction. Lower particle concentrations and fluxes were measured downwind from vegetated and residential areas compared to directions where the measurement site is downwind from roads passing near the measurement site. For these directions, contributions of the local sources on the measured particle concentrations and size distributions were evident. In particular, size distributions with a mode in the size range 20–40 nm were found to be more affected by local traffic emissions, whereas the mode shifted towards larger sizes when contribution from distant sources was more evident. Using flux footprint functions, mixed vehicle fleet emission factors (EFs) were derived from the particle flux measurements. EFs of 6.03 (±0.19)1014 # Veh−1 km−1 and 3.65 (±0.12)1014 # Veh−1 km−1 were estimated for cold (October–March) and warm (April–September) periods, respectively. Emission factors increased with decreasing air temperature (T) following a linear relationship EF=−0.201014 # Veh−1 km−1°C−1 T+6.981014 # Veh−1 km−1 (RMSE=3.71014 # Veh−1 km−1). |
| first_indexed | 2024-12-12T14:58:32Z |
| format | Article |
| id | doaj.art-5eb7fd06853a4b2db7b315aec3747095 |
| institution | Directory Open Access Journal |
| issn | 1600-0889 |
| language | English |
| last_indexed | 2024-12-12T14:58:32Z |
| publishDate | 2013-06-01 |
| publisher | Stockholm University Press |
| record_format | Article |
| series | Tellus: Series B, Chemical and Physical Meteorology |
| spelling | doaj.art-5eb7fd06853a4b2db7b315aec37470952022-12-22T00:20:51ZengStockholm University PressTellus: Series B, Chemical and Physical Meteorology1600-08892013-06-0165011710.3402/tellusb.v65i0.19786The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, FinlandGiovanna RipamontiLeena JärviBjarke MølgaardTareq HusseinAnnika NordboKaarle HämeriThree years of aerosol particle number concentrations (PNCs), size distributions and vertical particle fluxes measured at the semi-urban SMEAR III station in Helsinki, Finland, were studied. The purpose is to study the local emission sources and their effect on particle concentrations and size distributions. By means of cluster analysis, six representative size distributions were identified. Their occurrence together with particle concentrations and fluxes were found to vary significantly with wind direction. Lower particle concentrations and fluxes were measured downwind from vegetated and residential areas compared to directions where the measurement site is downwind from roads passing near the measurement site. For these directions, contributions of the local sources on the measured particle concentrations and size distributions were evident. In particular, size distributions with a mode in the size range 20–40 nm were found to be more affected by local traffic emissions, whereas the mode shifted towards larger sizes when contribution from distant sources was more evident. Using flux footprint functions, mixed vehicle fleet emission factors (EFs) were derived from the particle flux measurements. EFs of 6.03 (±0.19)1014 # Veh−1 km−1 and 3.65 (±0.12)1014 # Veh−1 km−1 were estimated for cold (October–March) and warm (April–September) periods, respectively. Emission factors increased with decreasing air temperature (T) following a linear relationship EF=−0.201014 # Veh−1 km−1°C−1 T+6.981014 # Veh−1 km−1 (RMSE=3.71014 # Veh−1 km−1).www.tellusb.net/index.php/tellusb/article/download/19786/pdf_1particle number size distributioneddy covarianceparticle fluxesvehicle emission factor |
| spellingShingle | Giovanna Ripamonti Leena Järvi Bjarke Mølgaard Tareq Hussein Annika Nordbo Kaarle Hämeri The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland Tellus: Series B, Chemical and Physical Meteorology particle number size distribution eddy covariance particle fluxes vehicle emission factor |
| title | The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland |
| title_full | The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland |
| title_fullStr | The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland |
| title_full_unstemmed | The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland |
| title_short | The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland |
| title_sort | effect of local sources on aerosol particle number size distribution concentrations and fluxes in helsinki finland |
| topic | particle number size distribution eddy covariance particle fluxes vehicle emission factor |
| url | http://www.tellusb.net/index.php/tellusb/article/download/19786/pdf_1 |
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