Agricultural harvesting emissions of ice-nucleating particles
<p>Agricultural activities can modify natural ecosystems and change the nature of the aerosols emitted from those landscapes. The harvesting of crops can loft plant fragments and soil dust into the atmosphere that can travel long distances and interact with clouds far from their sources. In...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2018-09-01
|
Series: | Atmospheric Chemistry and Physics |
Online Access: | https://www.atmos-chem-phys.net/18/13755/2018/acp-18-13755-2018.pdf |
Summary: | <p>Agricultural activities can modify natural ecosystems and change the nature
of the aerosols emitted from those landscapes. The harvesting of crops can
loft plant fragments and soil dust into the atmosphere that can travel long
distances and interact with clouds far from their sources. In this way
harvesting may contribute substantially to ice-nucleating particle (INP)
concentrations, especially in regions where agriculture makes up a large
percentage of land use. However, a full characterization of particles emitted
during harvesting has not been reported. This study characterizes immersion
mode INPs emitted during harvesting of several crops in the High Plains
region of the United States. The Colorado State University Continuous Flow
Diffusion Chamber (CFDC) and the Ice Spectrometer (IS) were utilized to
measure INP concentrations during active harvesting of four crops in Kansas
and Wyoming. Large spikes of INPs were observed during harvesting, with
concentrations over 200 L<sup>−1</sup> at −30 °C measured during a
wheat harvest. To differentiate between mineral and organic components, a
novel heating tube method was employed in real time upstream of the CFDC to
deactivate organic INPs in situ. The results indicate that harvesting
produces a complex mixture of organic, soil dust, and mineral components that
varies for different crops. Electron microscopy analysis showed that while
mineral components made up a large proportion of INPs, organic components
comprised over 40 % of measured INPs for certain crops at warm
temperatures. Heating and enzyme post-treatment of aerosol samples collected
for IS processing indicated that bacteria and heat-labile and heat-stable
organics contributed to wheat harvest-produced INPs. These results indicate
that plant material and organic particles are a significant component of
harvest INPs and their impacts on ice formation in clouds and precipitation
on a regional scale should be explored.</p> |
---|---|
ISSN: | 1680-7316 1680-7324 |