Ice-nucleating ability of particulate emissions from solid-biomass-fired cookstoves: an experimental study
<p>This research was part of the Salutary Umeå Study of Aerosols in Biomass Cookstove Emissions (SUSTAINE) laboratory experiment campaign. We studied ice-nucleating abilities of particulate emissions from solid-fuel-burning cookstoves, using a portable ice nuclei counter, Spectrometer Ice Nucl...
| Main Authors: | , , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-04-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/20/4951/2020/acp-20-4951-2020.pdf |
| Summary: | <p>This research was part of the Salutary Umeå Study of Aerosols
in Biomass Cookstove Emissions (SUSTAINE) laboratory experiment campaign. We
studied ice-nucleating abilities of particulate emissions from solid-fuel-burning cookstoves, using a portable ice nuclei counter, Spectrometer Ice
Nuclei (SPIN). These emissions were generated from two traditional cookstove
types commonly used for household cooking in sub-Saharan Africa and two
advanced gasifier stoves under research to promote sustainable development
alternatives. The solid fuels studied included biomass from two different
African tree species, Swedish softwood and agricultural residue products
relevant to the region. Measurements were performed with a modified version
of the standard water boiling test on polydisperse samples from flue gas
during burning and size-selected accumulation mode soot particles from a
15 m<span class="inline-formula"><sup>3</sup></span> aerosol-storage chamber. The studied soot particle sizes in nanometers
were 250, 260, 300, 350, 400, 450 and 500. From this chamber, the particles
were introduced to water-supersaturated freezing conditions (<span class="inline-formula">−</span>32 to <span class="inline-formula">−</span>43 <span class="inline-formula"><sup>∘</sup></span>C) in the SPIN.</p>
<p>Accumulation mode soot particles generally produced an ice-activated
fraction of 10<span class="inline-formula"><sup>−3</sup></span> in temperatures 1–1.5 <span class="inline-formula"><sup>∘</sup></span>C higher than that
required for homogeneous freezing at fixed RH<span class="inline-formula"><sub>w</sub>=115</span> %. In five
special experiments, the combustion performance of one cookstove was
intentionally modified. Two of these exhibited a significant increase in the
ice-nucleating ability of the particles, resulting in a 10<span class="inline-formula"><sup>−3</sup></span> ice
activation at temperatures up to 5.9 <span class="inline-formula"><sup>∘</sup></span>C higher than homogeneous
freezing and the observed increased ice-nucleating ability. We investigated
six different physico-chemical properties of the emission particles but
found no clear correlation between them and increasing ice-nucleating
ability. We conclude that the freshly emitted combustion aerosols form ice
via immersion and condensation freezing at temperatures only moderately above
homogeneous freezing conditions.</p> |
|---|---|
| ISSN: | 1680-7316 1680-7324 |