Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall
The processes removing aerosols from the atmosphere during rainfall are generically referred to as scavenging. Scavenging influences aerosol distributions in the atmosphere, with consequent effects on cloud properties, radiative forcing, and human health. In this study, we investigated the below-clo...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-01-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/11/1/80 |
| _version_ | 1828868897330167808 |
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| author | Rachel A. Moore Regina Hanlon Craig Powers David G. Schmale Brent C. Christner |
| author_facet | Rachel A. Moore Regina Hanlon Craig Powers David G. Schmale Brent C. Christner |
| author_sort | Rachel A. Moore |
| collection | DOAJ |
| description | The processes removing aerosols from the atmosphere during rainfall are generically referred to as scavenging. Scavenging influences aerosol distributions in the atmosphere, with consequent effects on cloud properties, radiative forcing, and human health. In this study, we investigated the below-cloud scavenging process, specifically focusing on the scavenging of 0.2 to 2 µm-sized microbial aerosols by populations of water drops with average diameters of 3.0 and 3.6 mm. Rainfall was simulated in convective boundary layer air masses by dispensing the water drops from a 55 m bridge and collecting them at ground level. Particles and microbial cells scavenged by the water drops were visualized, enumerated, and sized using scanning electron and epifluorescence microscopy. Aerosolized particles and DNA-containing microbial cells of 2 µm diameter were scavenged at efficiencies similar to those reported previously in empirical studies; however, the efficiencies derived for smaller aerosols were significantly higher (one to three orders of magnitude) than those predicted by microphysical modeling. Application of the derived scavenging efficiencies to cell data from rainfall implies that, on average, approximately 50 to 70% of the 1 µm microbial cells in the precipitation originated from within the cloud. Further study of submicron to micron-sized aerosol scavenging over a broader raindrop size distribution would improve fundamental understanding of the scavenging process and the capacity to estimate (bio)aerosol abundances in the source cloud through analysis of rainfall. |
| first_indexed | 2024-12-13T05:39:23Z |
| format | Article |
| id | doaj.art-150b98a8b9104ae9bf110e38210d76da |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-12-13T05:39:23Z |
| publishDate | 2020-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-150b98a8b9104ae9bf110e38210d76da2022-12-21T23:57:49ZengMDPI AGAtmosphere2073-44332020-01-011118010.3390/atmos11010080atmos11010080Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated RainfallRachel A. Moore0Regina Hanlon1Craig Powers2David G. Schmale3Brent C. Christner4Department of Microbiology and Cell Science, Biodiversity Institute, University of Florida, Gainesville, FL 32603, USASchool of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061-0390, USADepartment of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA 24061-0246, USASchool of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA 24061-0390, USADepartment of Microbiology and Cell Science, Biodiversity Institute, University of Florida, Gainesville, FL 32603, USAThe processes removing aerosols from the atmosphere during rainfall are generically referred to as scavenging. Scavenging influences aerosol distributions in the atmosphere, with consequent effects on cloud properties, radiative forcing, and human health. In this study, we investigated the below-cloud scavenging process, specifically focusing on the scavenging of 0.2 to 2 µm-sized microbial aerosols by populations of water drops with average diameters of 3.0 and 3.6 mm. Rainfall was simulated in convective boundary layer air masses by dispensing the water drops from a 55 m bridge and collecting them at ground level. Particles and microbial cells scavenged by the water drops were visualized, enumerated, and sized using scanning electron and epifluorescence microscopy. Aerosolized particles and DNA-containing microbial cells of 2 µm diameter were scavenged at efficiencies similar to those reported previously in empirical studies; however, the efficiencies derived for smaller aerosols were significantly higher (one to three orders of magnitude) than those predicted by microphysical modeling. Application of the derived scavenging efficiencies to cell data from rainfall implies that, on average, approximately 50 to 70% of the 1 µm microbial cells in the precipitation originated from within the cloud. Further study of submicron to micron-sized aerosol scavenging over a broader raindrop size distribution would improve fundamental understanding of the scavenging process and the capacity to estimate (bio)aerosol abundances in the source cloud through analysis of rainfall.https://www.mdpi.com/2073-4433/11/1/80rain scavengingaerosolsbioaerosolswet deposition |
| spellingShingle | Rachel A. Moore Regina Hanlon Craig Powers David G. Schmale Brent C. Christner Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall Atmosphere rain scavenging aerosols bioaerosols wet deposition |
| title | Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall |
| title_full | Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall |
| title_fullStr | Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall |
| title_full_unstemmed | Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall |
| title_short | Scavenging of Sub-Micron to Micron-Sized Microbial Aerosols during Simulated Rainfall |
| title_sort | scavenging of sub micron to micron sized microbial aerosols during simulated rainfall |
| topic | rain scavenging aerosols bioaerosols wet deposition |
| url | https://www.mdpi.com/2073-4433/11/1/80 |
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