Survival probabilities of atmospheric particles: comparison based on theory, cluster population simulations, and observations in Beijing
<p>Atmospheric new particle formation (NPF) events are regularly observed in urban Beijing, despite high concentrations of background particles which, based on theory, should inhibit NPF due to high values of coagulation sink (CoagS). The survival probability, which depends on both CoagS and p...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-11-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://acp.copernicus.org/articles/22/15071/2022/acp-22-15071-2022.pdf |
| Summary: | <p>Atmospheric new particle formation (NPF) events are regularly observed in
urban Beijing, despite high concentrations of background particles which,
based on theory, should inhibit NPF due to high values of coagulation sink
(CoagS). The survival probability, which depends on both CoagS and particle
growth rate (GR), is a key parameter in determining the occurrence of NPF events
as it describes the fraction of newly formed particles that survive from a
smaller diameter to a larger diameter. In this study, we investigate and
compare survival probabilities from 1.5 to 3 nm (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">3</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">1.5</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="36pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="dd965924e58000091851a6e4ed477e28"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00001.svg" width="36pt" height="14pt" src="acp-22-15071-2022-ie00001.png"/></svg:svg></span></span>), from 3 to
6 nm (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">6</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">3</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="1eaddf744c9d5dd53aebbecd0288f323"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00002.svg" width="29pt" height="14pt" src="acp-22-15071-2022-ie00002.png"/></svg:svg></span></span>), and from 6 to 10 nm (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">10</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">6</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="34pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="49d86c438e0c64b85c142a1ab456cbde"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00003.svg" width="34pt" height="14pt" src="acp-22-15071-2022-ie00003.png"/></svg:svg></span></span>) based on analytical
formulae, cluster population simulations, and atmospheric observations from
Beijing. We find that survival probabilities based on the cluster population
simulations and one of the analytical formulae are in a good agreement.
However, at low ratios between the background condensation sink (CS) and GR,
and at high concentrations of sub-3 nm clusters, cluster–cluster collisions
efficiently lower survival probabilities in the cluster population
simulations. Due to the large concentrations of clusters and small particles
required to considerably affect the survival probabilities, we consider it
unlikely that cluster–cluster collisions significantly affect atmospheric
survival probabilities. The values of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">10</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">6</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="34pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="25ea32ecf12495eb1b08cd89db35091b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00004.svg" width="34pt" height="14pt" src="acp-22-15071-2022-ie00004.png"/></svg:svg></span></span> observed in Beijing show
high variability, most likely due to influences of primary particle
emissions, but are on average in relatively good agreement with the values
based on the simulations and the analytical formulae. The observed values of
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">6</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">3</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="fcac4618edd0923ee34ec1f6229020e2"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00005.svg" width="29pt" height="14pt" src="acp-22-15071-2022-ie00005.png"/></svg:svg></span></span> are mostly lower than those predicted based on the simulations
and the analytical formulae, which could be explained by uncertainties in CS
and GR. The observed values of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">3</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">1.5</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="36pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="250082fe391bcca4a9e098d719c256ae"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00006.svg" width="36pt" height="14pt" src="acp-22-15071-2022-ie00006.png"/></svg:svg></span></span> at high CS <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="36bd7baae116a5efc17e692d563c2b51"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00007.svg" width="8pt" height="14pt" src="acp-22-15071-2022-ie00007.png"/></svg:svg></span></span> GR are much higher
than predicted based on the simulations and the analytical formulae. We argue
that uncertainties in GR or CS are unlikely to solely explain the observed
values of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>J</mi><mn mathvariant="normal">3</mn></msub><mo>/</mo><msub><mi>J</mi><mn mathvariant="normal">1.5</mn></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="36pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="942fa8b0342fc9c4a2ff5941601734d0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-22-15071-2022-ie00008.svg" width="36pt" height="14pt" src="acp-22-15071-2022-ie00008.png"/></svg:svg></span></span> under high CS conditions. Thus, further work is
needed to better understand the factors influencing survival probabilities
of sub-3 nm atmospheric particles in polluted environments.</p> |
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| ISSN: | 1680-7316 1680-7324 |