English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This study is concerned with the impacts of organic aerosols on cloud condensation nuclei (CCN) activitybased on field measurements made at a suburban site in Northern China. Thesensitivity of the estimated CCN number concentration (NCCN) to bothvolume fraction of organic material (xorg) and aerosol oxidation level(using f44, the fraction of m∕z 44 in aerosol organic material)are examined. A strong dependence of CCN number concentration (NCCN) onthe xorg and f44 was noted. The sensitivity of NCCN to volumefraction of organics increased with increasing xorg. The impacts of theaerosol particles oxidization or aging level on estimating NCCN werealso very significant. When the particles were mostly composed of organics(xorg > 60 %), the NCCN at the supersaturation of0.075 and 0.13 % was underestimated by 46 and 44 %, respectively,if aerosol particles were freshly emitted with primary organics(f44 < 11 %); the underestimation decreased to 32 and23 % at the corresponding supersaturations, however, if the particles were with morehygroscopic secondary organics (f44 > 15 %). The NCCN atthe supersaturation of 0.76 % was underestimated by 11 and 4 %,respectively, at f44 < 11 and f44 > 15 %.However,for the particles composed of low organics (e.g., xorg < 40 %),the effect caused by the f44 was quite insignificant both at high andlow supersaturations. This is because the overall hygroscopicity of theparticles is dominated by inorganics such as sulfate and nitrate, which aremore hygroscopic than organic compounds. Our results indicated that it woulddecrease the uncertainties in estimating NCCN and lead to a moreaccurate estimation of NCCN to increase the proportion of secondaryorganics, especially when the composition of the aerosols is dominated byorganics. The applicability of the CCN activation spectrum obtained atXinzhou to the Xianghe site, about 400 km to the northeast of Xinzhou, wasinvestigated, with the aim of further examining the sensitivity of NCCNto aerosol type. Overall, the mean CCN efficiency spectrum derived fromXinzhou performs well at Xianghe when the supersaturation levels are> 0.2 % (overestimation of 2–4 %). However, NCCN wasoverestimated by  ∼  20 % at supersaturation levels of< 0.1 %. This suggests that the overestimation is mainly due tothe smaller proportion of aged and oxidized organic aerosols present atXianghe compared to Xinzhou

Impacts of organic aerosols and its oxidation level on CCN activity from measurement at a suburban site in China