Precursor apportionment of atmospheric oxygenated organic molecules using a machine learning method

Environmental Science Atmospheres, Год журнала: 2022, Номер 3(1), С. 230 - 237

Опубликована: Дек. 3, 2022

Machine learning is a promising tool in atmospheric chemistry to connect oxygenated organic molecules with their precursors.

Язык: Английский

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Size-dependent chemical composition of atmospheric nanoparticles in urban Beijing during springtime

Atmospheric Environment, Год журнала: 2023, Номер 310, С. 119970 - 119970

Опубликована: Июль 20, 2023

Язык: Английский

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Substantially positive contributions of new particle formation to cloud condensation nuclei under low supersaturation in China based on numerical model improvements

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(18), С. 10713 - 10730

Опубликована: Сен. 27, 2023

Abstract. New particle formation (NPF) and subsequent growth are important sources of condensation nuclei (CN) cloud (CCN). While many observations have shown positive contributions NPF to CCN at low supersaturation, negative were often simulated in polluted environments. Using the a coastal city Qingdao, Beijing, Gucheng north China, we thoroughly evaluate number concentrations CN using an NPF-explicit parameterization embedded WRF-Chem model. For CN, initial simulation shows large biases 10–40 40–100 nm. By adjusting process gas–particle partitioning, including mass accommodation coefficient (MAC) sulfuric acid, phase changes primary organic aerosol emissions, condensational amount nitric improvement yields substantially reduced overestimation CN. Regarding CCN, secondary (SOA) formed from oxidation semi-volatile intermediate-volatility compounds (S/IVOCs) is called SI-SOA, yield which contributor. At default settings, SI-SOA too high without considering differences precursor rates. Lowering under linear H2SO4 nucleation scheme results much-improved simulations compared observations. On basis bias-corrected model, find supersaturation (∼ 0.2 %) over broad areas primarily due competing effects increasing hygroscopicity, result reductions amount, surpassing that size decreases. The model robustly applicable other schemes, such as quadratic scheme, terms though dependence on diminished likely composition. This study highlights potentially much larger regional even global basis.

Язык: Английский

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Revealing the sources and sinks of negative cluster ions in an urban environment through quantitative analysis

Atmospheric chemistry and physics, Год журнала: 2023, Номер 23(9), С. 5279 - 5296

Опубликована: Май 11, 2023

Abstract. Atmospheric cluster ions are important constituents in the atmosphere, and their concentrations compositions govern role atmospheric chemistry. However, there is currently limited quantitative research on ion compositions, sources, sinks, especially urban atmosphere where pollution levels human populations intense. In this study, we measured of negative neutral molecules using an pressure interface high-resolution time-of-flight mass spectrometer (APi-TOF) a chemical ionization Beijing. Quantitative analysis was performed by comparison with condensation sink (CS), reagent ions, molecules. We demonstrate feasibility quantifying different situ-measured mobility distributions from air (NAIS). The median concentration 85 (61–112 for 25 %–75 %) cm−3 during measurement period, which negatively correlated CS. mainly consisted inorganic nitrogen-containing sulfur-containing organic form adducts NO3- or HSO4-. CHON-related accounted over 70 % total ions. Although clustered HSO4- had similar found that more efficiently CHO CHONnonNPs species (CHON excluding nitrated phenols), while phenols (CHONNPs). Additionally, most were positively molecules, resulting diurnal cycles exception CHONNPs, also significantly influenced NO3-. charge fractions generally higher molecular weight oxidation state, opposite variations charging between H2SO4 indicate competition them. Finally, choose C3H3O4- as representatives to calculate contribution formation loss pathways. losses condensational onto aerosol particles (73 %), ion–molecule reaction (19 ion–ion recombination (6 %–8 %).

Язык: Английский

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New mechanism for the participation of aromatic oxidation products in atmospheric nucleation

The Science of The Total Environment, Год журнала: 2024, Номер 917, С. 170487 - 170487

Опубликована: Янв. 29, 2024

Язык: Английский

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