Reactive Uptake Research Articles

Suppression of surface ozone by an aerosol-inhibited photochemical ozone regime

Atmospheric ozone (O3) is a pollutant produced through chemical chain reactions where volatile organic compounds (VOCs), carbon monoxide and methane are oxidized in the presence of oxides of nitrogen (NOx). For decades, the controlling chain termination step has been used to separate regions into either ‘NOx limited’ (peroxyl-radical self-reactions dominate) or ‘VOC limited’ (hydroxyl radical (OH) + nitrogen dioxide (NO2) reaction dominates). The controlling regime would then guide policies for reducing emissions and so O3 concentrations. Using a chemical transport model, we show that a third ‘aerosol inhibited’ regime exists, where reactive uptake of hydroperoxyl radicals (HO2) onto aerosol particles dominates. In 1970, 2% of the Northern Hemisphere population lived in an aerosol-inhibited regime, but by 2014 this had increased to 21%; 60% more than lived in a VOC-limited regime. Aerosol-inhibited chemistry suppressed surface O3 concentrations in North America and Europe in the 1970s and is currently suppressing surface O3 over Asia. This third photochemical O3 regime leads to potential trade-off tensions between reducing particle pollution in Asia (a key current health policy and priority) and increasing surface O3, should O3 precursors emissions not be reduced in tandem.

Reactive Uptake of Hydroperoxymethyl Thioformate to Sodium Chloride and Sodium Iodide Aerosol Particles.

The oxidation products of dimethyl sulfide (DMS) contribute to the production and growth of cloud condensation nuclei (CCN) in the marine boundary layer. Recent work demonstrates that DMS is oxidized by OH radicals to the stable intermediate hydroperoxymethyl thioformate (HPMTF), which is both globally ubiquitous and efficiently lost to multiphase processes in the marine atmosphere. At present, there are no experimental measurements of the reactive uptake of HPMTF to aerosol particles, limiting model implementation of multiphase HPMTF chemistry. Using an entrained aerosol flow reactor combined with chemical ionization mass spectrometry (CIMS), we measured the reactive uptake coefficient (γ) of HPMTF to dry sodium chloride (NaCl), wet NaCl, and wet sodium iodide (NaI) particles to be (1.9 ± 1.3) × 10-4, (1.6 ± 0.6) × 10-3, and (9.2 ± 2.3) × 10-1, respectively. While we did not directly measure the condensed-phase products of HPMTF reactive uptake in this experiment, the ionization products observed in the CIMS instrument provide mechanistic insight on the reaction mechanism of HPMTF with halides.

Modeling Reactive Ammonia Uptake by Secondary Organic Aerosol in a Changing Climate: A WRF-CMAQ Evaluation

In addition to the well-constrained inorganic acid-base chemistry of ammonia resulting in fine particulate matter (PM2.5) formation, ammonia also reacts with certain organic compounds in secondary organic aerosol (SOA) to produce less basic nitrogen-containing organic compounds. In this study, the potential meteorology and air quality impacts of the heterogeneous uptake of NH3 by SOA are investigated using the WRF-CMAQ two-way coupled model, which calculates the two-way radiative forcing feedback caused by aerosol between meteorology and chemistry in a single simulation. Simulations with and without the NH3-SOA uptake are performed over the contiguous US for July 2014 and July 2050 under the RCP 8.5 IPCC scenario to study the potential impact of climate change. A comparison with multiple observation network data shows that the NH3-SOA uptake improves the model performance for PM2.5 prediction (bias reduced from −22% to −17%), especially the underestimation of organic carbon over the Southeastern US (bias reduced from −17% to −7%). Secondly, the addition of the NH3-SOA chemistry significantly impacts the concentration of NH3 and NH4+, thus affecting the modeled particle acidity. Including the NH3-SOA uptake also impacts the meteorological conditions through the WRF-CMAQ two-way feedback. Moreover, the impact on meteorological conditions results in different windspeed or dispersion conditions, thus affecting air quality predictions. Finally, simulations including the NH3-SOA uptake under the warmer climate conditions of 2050 show a smaller impact on air quality predictions than it does under current climate conditions. This study confirms the importance and necessity of including NH3-SOA chemistry in air quality predictions.

Morphology and Viscosity Changes after Reactive Uptake of Isoprene Epoxydiols in Submicrometer Phase Separated Particles with Secondary Organic Aerosol Formed from Different Volatile Organic Compounds

Morphology and Viscosity Changes after Reactive Uptake of Isoprene Epoxydiols in Submicrometer Phase Separated Particles with Secondary Organic Aerosol Formed from Different Volatile Organic Compounds

Uptake of N2O5 by aqueous aerosol unveiled using chemically accurate many-body potentials

The reactive uptake of N2O5 to aqueous aerosol is a major loss channel for nitrogen oxides in the troposphere. Despite its importance, a quantitative picture of the uptake mechanism is missing. Here we use molecular dynamics simulations with a data-driven many-body model of coupled-cluster accuracy to quantify thermodynamics and kinetics of solvation and adsorption of N2O5 in water. The free energy profile highlights that N2O5 is selectively adsorbed to the liquid–vapor interface and weakly solvated. Accommodation into bulk water occurs slowly, competing with evaporation upon adsorption from gas phase. Leveraging the quantitative accuracy of the model, we parameterize and solve a reaction–diffusion equation to determine hydrolysis rates consistent with experimental observations. We find a short reaction–diffusion length, indicating that the uptake is dominated by interfacial features. The parameters deduced here, including solubility, accommodation coefficient, and hydrolysis rate, afford a foundation for which to consider the reactive loss of N2O5 in more complex solutions.

The number fraction of iron-containing particles affects OH, HO<sub>2</sub> and H<sub>2</sub>O<sub>2</sub> budgets in the atmospheric aqueous phase

Abstract. Reactive oxygen species (ROS), such as OH, HO2 and H2O2, affect the oxidation capacity of the atmosphere and cause adverse health effects of particulate matter. The role of transition metal ions (TMIs) in impacting the ROS concentrations and conversions in the atmospheric aqueous phase has been recognized for a long time. Model studies usually assume that the total TMI mass as measured in bulk aerosol or cloud water samples is distributed equally across all particles or droplets. This assumption is contrary to single-particle measurements that have shown that only a small number fraction of particles contain iron and other TMIs (FN,Fe<100 %), which implies that also not all cloud droplets contain TMIs. In the current study, we apply a box model with an explicit multiphase chemical mechanism to simulate ROS formation and cycling in aqueous aerosol particles and cloud droplets. Model simulations are performed for the range of 1 % ≤ FN,Fe ≤ 100 % for constant pH values of 3, 4.5 and 6 and constant total iron mass concentration (10 or 50 ng per cubic meter of air). Model results are compared for two sets of simulations with FN,Fe<100 % (FeN<100) and 100 % (FeBulk). We find the largest differences between model results in OH and HO2 / O2- concentrations at pH = 6. Under these conditions, HO2 is subsaturated in the aqueous phase because of its high effective Henry's law constant and the fast chemical loss reactions of the O2- radical anion. As the main reduction process of Fe(III) is its reaction with HO2 / O2-, we show that the HO2 subsaturation leads to Fe(II) / Fe(total) ratios for FN,Fe<100 % that are lower by a factor of ≤ 2 as compared to bulk model approaches. This trend is largely independent of the total iron concentration, as both chemical source and sink rates of HO2 / O2- scale with the iron concentration. We compare model-derived reactive uptake parameters γOH and γHO2 for the full range of FN,Fe. While γOH is not affected by the iron distribution, the calculated γHO2 values range from 0.0004 to 0.03 for FN,Fe = 1 % and 100 %, respectively. Implications of these findings are discussed for the application of lab-derived γHO2 in models to present reactive HO2 uptake on aerosols. We conclude that the iron distribution (FN,Fe) should be taken into account to estimate the ROS concentrations and oxidation potential of particulate matter that might be overestimated by bulk sampling and model approaches. Our study suggests that the number concentration of iron-containing particles FN,Fe may be more important than the total iron mass concentration in determining ROS budgets and uptake rates in cloud and aerosol water.

18F]FDG uptake in axillary lymph nodes and deltoid muscle after COVID-19 mRNA vaccination: a cohort study to determine incidence and contributing factors using a multivariate analysis.

PurposeReactive FDG uptake in the axillary lymph nodes (ALN) and deltoid muscle (DM) after COVID-19 mRNA vaccination has been recognized, although the actual situation in the Japanese population remains unknown. To determine the incidence of reactive FDG uptake and its contributing factors, we retrospectively studied a cohort of subjects who were vaccinated at our hospital.MethodsWhole-body FDG-PET/CT examinations performed in 237 subjects out of 240 subjects with a definite history of COVID-19 vaccination (BNT162b2; BioNTech-Pfizer) were analyzed. Positivity and SUVmax of FDG uptake in the ALN and DM ipsilateral to vaccination, various subject characteristics, and the grade of the pathological FDG-PET/CT findings were evaluated using a multivariate analysis.ResultsFDG uptake in the ALN and DM ipsilateral to vaccination was seen in about 60% of the subjects even soon (0–4 days) after the first vaccination, with percentages reaching 87.5% and 75.0%, respectively, after the second vaccination. DM uptake had almost disappeared at around 2 weeks, while ALN uptake persisted for 3 weeks or longer. A multivariate analysis showed that a short duration since vaccination, a younger age, a female sex, and a low FDG-PET/CT grade (minimal pathological FDG uptake) contributed significantly to positive ALN uptake, while a short duration since vaccination and a female sex were the only significant contributors to positive DM uptake. This study is the first to identify factors contributing to positive FDG uptake in ALN and DM after COVID-19 vaccination.ConclusionA high incidence of FDG uptake in ALN and DM was observed after vaccination. ALN uptake seemed to be associated with a younger age, a female sex, and minimal pathological FDG uptake. After vaccination, an acute inflammatory reaction in DM followed by immune reaction in ALN linked to humoral immunity may be speculated.

Field observational constraints on the controllers in glyoxal (CHOCHO) reactive uptake to aerosol

Abstract. Glyoxal (CHOCHO), the simplest dicarbonyl in the troposphere, is a potential precursor for secondary organic aerosol (SOA) and brown carbon (BrC) affecting air quality and climate. The airborne measurement of CHOCHO concentrations during the KORUS-AQ (KORea–US Air Quality study) campaign in 2016 enables detailed quantification of loss mechanisms pertaining to SOA formation in the real atmosphere. The production of this molecule was mainly from oxidation of aromatics (59 %) initiated by hydroxyl radical (OH). CHOCHO loss to aerosol was found to be the most important removal path (69 %) and contributed to roughly ∼ 20 % (3.7 µg sm−3 ppmv−1 h−1, normalized with excess CO) of SOA growth in the first 6 h in Seoul Metropolitan Area. A reactive uptake coefficient (γ) of ∼ 0.008 best represents the loss of CHOCHO by surface uptake during the campaign. To our knowledge, we show the first field observation of aerosol surface-area-dependent (Asurf) CHOCHO uptake, which diverges from the simple surface uptake assumption as Asurf increases in ambient condition. Specifically, under the low (high) aerosol loading, the CHOCHO effective uptake rate coefficient, keff,uptake, linearly increases (levels off) with Asurf; thus, the irreversible surface uptake is a reasonable (unreasonable) approximation for simulating CHOCHO loss to aerosol. Dependence on photochemical impact and changes in the chemical and physical aerosol properties “free water”, as well as aerosol viscosity, are discussed as other possible factors influencing CHOCHO uptake rate. Our inferred Henry's law coefficient of CHOCHO, 7.0×108 M atm−1, is ∼ 2 orders of magnitude higher than those estimated from salting-in effects constrained by inorganic salts only consistent with laboratory findings that show similar high partitioning into water-soluble organics, which urges more understanding on CHOCHO solubility under real atmospheric conditions.

Tight Coupling of Surface and In-Plant Biochemistry and Convection Governs Key Fine Particulate Components over the Amazon Rainforest

Combining unique high-altitude aircraft measurements and detailed regional model simulations, we show that in-plant biochemistry plays a central but previously unidentified role in fine particulate-forming processes and atmosphere–biosphere–climate interactions over the Amazon rainforest. Isoprene epoxydiol secondary organic aerosols (IEPOX-SOA) are key components of sub-micrometer aerosol particle mass throughout the troposphere over the Amazon rainforest and are traditionally thought to form by multiphase chemical pathways. Here, we show that these pathways are strongly inhibited by the solid thermodynamic phase state of aerosol particles and lack of particle and cloud liquid water in the upper troposphere. Strong diffusion limitations within organic aerosol coatings prevailing at low temperatures and low relative humidity in the upper troposphere strongly inhibit the reactive uptake of IEPOX to inorganic aerosols. We find that direct emissions of 2-methyltetrol gases formed by in-plant biochemical oxidation and/or oxidation of deposited IEPOX gases on the surfaces of soils and leaves and their transport by cloud updrafts followed by their condensation at low temperatures could explain over 90% of the IEPOX-SOA mass concentrations in the upper troposphere. Our simulations indicate that even near the surface, direct emissions of 2-methyltetrol gases represent a ubiquitous, but previously unaccounted for, source of IEPOX-SOA. Our results provide compelling evidence for new pathways related to land surface–aerosol–cloud interactions that have not been considered previously.

Reactive uptake of ozone to azo dyes in a coated-wall flow tube.

Azo dyes are the most common colorants in consumer products, including clothing and cosmetics. Some azo dyes and their products from reductive degradation are known to be mutagenic, so dermal exposure to these species has been studied extensively. In contrast, oxidative degradation of azo dyes in consumer products has not been studied so thoroughly. In the indoor environment, ozone is ubiquitous, so reactive uptake of ozone to azo dyes could lead to dermal exposure to other classes of degradation products. Here, we report the first measurements of the reactive uptake of ozone to thin films of three widely used commercial azo dyes: sunset yellow, amaranth, and tartrazine. Steady-state uptake was observed for all three dyes, under all conditions investigated, even at the lowest relative humidity (RH) of 0%. The uptake coefficients increased with RH. For sunset yellow at 100 ppb of ozone, the value at 80% RH, (2.0 ± 0.5) × 10-7, was 2.5 times greater than that at 0% RH, (8 ± 1) × 10-8, consistent with plasticization of the thin film due to absorption of water. The uptake coefficient of sunset yellow at 80% RH exhibited an inverse dependence on the ozone mixing ratio, approaching an asymptote of 1 × 10-7 above 250 ppb. At 80% RH and 100 ppb of ozone, the uptake coefficients for the three dyes were similar, (2.0 ± 0.5) × 10-7 for sunset yellow, (2.7 ± 0.6) × 10-7 for amaranth, and (3.2 ± 0.3) × 10-7 for tartrazine, despite differences in structural parameters related to the number of reactive sites at the surface. Together, these results are consistent with ozone diffusing into the thin film and the dye molecules mixing between the layers, such that reaction is not restricted to the surface of the film. Finally, the results are suggestive of a role for azo dyes, including the occurrence of their oxidation products, in indoor chemistry.

Reactive Uptake of Monoethanolamine by Sulfuric Acid Particles and Hygroscopicity of Monoethanolaminium Salts

Reactive Uptake of Monoethanolamine by Sulfuric Acid Particles and Hygroscopicity of Monoethanolaminium Salts

Effect of Humidity on the Reactive Uptake of Ammonia and Dimethylamine by Nitrogen-Containing Secondary Organic Aerosol

This study investigated the uptake of ammonia (NH3) by secondary organic aerosol (SOA) particles generated via limonene photooxidation or ozonolysis as well as the uptake of dimethylamine (DMA) by limonene ozonolysis, α-cedrene photooxidation, or toluene photooxidation SOA in an environmental chamber between 0–50% relative humidity. In addition to the acid-base equilibrium uptake, NH3 and DMA can react with SOA carbonyl compounds converting them into nitrogen-containing organic compounds (NOCs). The effective reactive uptake coefficients for the formation of NOCs from ammonia were measured on the order of 10−5. The observed DMA reactive uptake coefficients ranged from 10−5 to 10−4. Typically, the reactive uptake coefficient decreased with increasing relative humidity. This is consistent with NOC formation by a condensation reaction between NH3 or DMA with SOA, which produces water as a product. Ammonia is more abundant in the atmosphere than amines. However, the larger observed reactive uptake coefficient suggests that amine uptake may also be a potential source of organic nitrogen in particulate matter.

Modeling the Size Distribution and Chemical Composition of Secondary Organic Aerosols during the Reactive Uptake of Isoprene-Derived Epoxydiols under Low-Humidity Condition

Modeling the Size Distribution and Chemical Composition of Secondary Organic Aerosols during the Reactive Uptake of Isoprene-Derived Epoxydiols under Low-Humidity Condition

Particle hygroscopicity inhomogeneity and its impact on reactive uptake

Atmospheric particles are important reaction vessels for multiphase chemistry. We conducted a meta-analysis of previous field observations in various environments (includes ocean, urban and rural regions), showing that particle hygroscopicity inhomogeneity (PHI) is ubiquitous for the continental atmospheric particles, in which a considerable part of the particulate matters is hydrophobic (10%–33% on average). However, the effects of PHI in quantifying the uptake process of reactive gases are still unclear. Here, taking N2O5 uptake as an example, we showed that using a laboratory-based parameterization scheme without considering the PHI might result in a misestimation of uptake rate coefficient, especially under low ambient relative humidity (RH). Such misestimation may be caused by the differences of the uptake coefficients, as well as the proportion of surface area concentration (SA) between hydrophilic and hydrophobic particles. We suggested that the PHI should be well-considered in establishing the reactive traces gases heterogeneous uptake parameterizations.

Photocatalytic Properties of TiO2 for the Degradation of O3: Examined by Environmental Parameters

Background: This paper describes how environmentally relevant parameters affect titanium dioxide's photocatalytic properties (TiO2) to decompose ozone (O3). Methods: Thus, experiments have been carried out in a box chamber with TiO2 coated roofing membrane samples to determine the significance of light intensity, temperature, initial O3 concentration, and relative humidity. Furthermore, an outdoor experiment was conducted where the roofing membrane was subjected to natural sunlight. Results: The results show a significant photocatalytic effect of TiO2. The half-life of the O3 decay curve is 5.8 min in near-ambient UV-light exposure compared with 7.1 min in dark conditions. Experiments conducted at higher light intensity show a more extensive degradation of O3, where the value of the reactive uptake coefficient increases from 0.044 to 0.051. Also, the measurements carried out under natural sunlight show a photocatalytic effect where the uptake coefficient value is 0.046. A larger photocatalytic effect is detected for the experiments conducted at 283 K and 303 K temperatures compared with experiments under standard conditions. Conclusion: Experiments carried out with a very high initial concentration of O3 show that 28.1 μg of O3 is decomposed in ambient conditions, where 2.3 μg is destroyed. This demonstrates that light intensity, temperature, ozone concentration, and relative humidity significantly impact TiO2's degradation of O3.

Modeling Volatility-Based Aerosol Phase State Predictions in the Amazon Rainforest

Organic aerosol (OA) is a complex matrix of various constituents—fresh (primary organic aerosols—POA) and aged via oxidation (secondary organic aerosols—SOA), generated from biogenic, anthropogenic, and biomass burning sources. The viscosity of OA can be critical in influencing new particle formation, reactive uptake processes that impact evaporation-growth kinetics, and the lifetime of particles in the atmosphere. This work utilizes a well-defined relationship between volatility and viscosity for pure compounds, which we incorporated within the Weather Research and Forecasting Model coupled to chemistry (WRF-Chem) to simulate the phase state and viscosity of bulk OA during the dry-to-wet transition season (September–October) in the Amazon rainforest during 2014. Our simulations indicate spatial and temporal heterogeneity in aerosol phase state often not captured by global-scale models. We show the strong role of water associated with organic aerosol (ws) as the dominant factor that can be used to quantitatively estimate OA viscosity. Analysis of WRF-Chem simulations across the entire atmospheric column indicates a strong inverse log-linear relationship between ws and OA viscosity with a correlation coefficient approaching 1, in the background and biomass burning-influenced conditions. At high altitudes where relative humidity (RH) and temperatures are low, our simulations indicate that OA exists in a semisolid-/solid-like phase state, consistent with previous studies. OA hygroscopicity is strongly correlated (ca. −0.8) with OA viscosity at RH ca. 30–50%, but this RH range is found mostly at low OA concentrations and the middle troposphere (ca. 6–10 km altitudes) in our simulated domain. OA hygroscopicity is uncorrelated with viscosity at higher-RH (near surface) and lower-RH (upper troposphere) regimes. At the urban site near surface, where day–night differences in RH are significant, RH is found to drive the phase state. At the background forested site near surface, where day–night RH differences are small, biomass burning-influenced OA is semisolid and a significant OA associated with background conditions is liquid-like. Simulations indicate a long tail of OA viscosity frequency distributions extending in the semisolid/solid regimes over background biogenic-influenced conditions due to the role of low-volatility OA components such as monoterpene oxidation products.

Potential of Vasoprotectives to Inhibit Non-Enzymatic Protein Glycation, and Reactive Carbonyl and Oxygen Species Uptake.

Reactive carbonyl species (RCS) such as methylglyoxal (MGO) or glyoxal (GO) are the main precursors of the formation of advanced glycation end products (AGEs). AGEs are a major factor in the development of vascular complications in diabetes. Vasoprotectives (VPs) exhibit a wide range of activities beneficial to cardiovascular health. The present study aimed to investigate selected VPs and their structural analogs for their ability to trap MGO/GO, inhibit AGE formation, and evaluate their antioxidant potential. Ultra-high-performance liquid chromatography coupled with an electrospray ionization mass spectrometer (UHPLC-ESI-MS) and diode-array detector (UHPLC-DAD) was used to investigate direct trapping capacity and kinetics of quenching MGO/GO, respectively. Fluorimetric and colorimetric measurements were used to evaluate antiglycation and antioxidant action. All tested substances showed antiglycative effects, but hesperetin was the most effective in RCS scavenging. We demonstrated that rutin, diosmetin, hesperidin, and hesperetin could trap both MGO and GO by forming adducts, whose structures we proposed. MGO-derived AGE formation was inhibited the most by hesperetin, and GO-derived AGEs by diosmetin. High reducing and antiradical activity was confirmed for quercetin, rutin, hesperetin, and calcium dobesilate. Therefore, in addition to other therapeutic applications, some VPs could be potential candidates as antiglycative agents to prevent AGE-related complications of diabetes.

Role of Copper on Mitochondrial Function and Metabolism.

Copper is essential for life processes like energy metabolism, reactive oxygen species detoxification, iron uptake, and signaling in eukaryotic organisms. Mitochondria gather copper for the assembly of cuproenzymes such as the respiratory complex IV, cytochrome c oxidase, and the antioxidant enzyme superoxide dismutase 1. In this regard, copper plays a role in mitochondrial function and signaling involving bioenergetics, dynamics, and mitophagy, which affect cell fate by means of metabolic reprogramming. In mammals, copper homeostasis is tightly regulated by the liver. However, cellular copper levels are tissue specific. Copper imbalances, either overload or deficiency, have been associated with many diseases, including anemia, neutropenia, and thrombocytopenia, as well as tumor development and cancer aggressivity. Consistently, new pharmacological developments have been addressed to reduce or exacerbate copper levels as potential cancer therapies. This review goes over the copper source, distribution, cellular uptake, and its role in mitochondrial function, metabolic reprograming, and cancer biology, linking copper metabolism with the field of regenerative medicine and cancer.

Clinical Perspective: Greater Magnitude of Reactive Nodal Uptake Following COVID-19 mRNA Vaccination Compared to Traditional Influenza Vaccination

Clinical Perspective: Greater Magnitude of Reactive Nodal Uptake Following COVID-19 mRNA Vaccination Compared to Traditional Influenza Vaccination

Gas–particle partitioning of polyol tracers at a suburban site in Nanjing, east China: increased partitioning to the particle phase

Abstract. Gas–particle partitioning of water-soluble organic compounds plays a significant role in influencing the formation, transport, and lifetime of organic aerosols in the atmosphere, but is poorly characterized. In this work, gas- and particle-phase concentrations of isoprene oxidation products (C5-alkene triols and 2-methylterols), levoglucosan, and sugar polyols were measured simultaneously at a suburban site of the western Yangtze River Delta in east China. All target polyols were primarily distributed into the particle phase (85.9 %–99.8 %). Given the uncertainties in measurements and vapor pressure predictions, a dependence of particle-phase fractions on vapor pressures cannot be determined. To explore the impact of aerosol liquid water on gas–particle partitioning of polyol tracers, three partitioning schemes (Cases 1–3) were proposed based on equilibriums of gas vs. organic and aqueous phases in aerosols. If particulate organic matter (OM) is presumed as the only absorbing phase (Case 1), the measurement-based absorptive partitioning coefficients (Kp,OMm) of isoprene oxidation products and levoglucosan were more than 10 times greater than predicted values (Kp,OMt). The agreement between Kp,OMm and Kp,OMt was substantially improved when solubility in a separate aqueous phase was included, whenever water-soluble and water-insoluble OM partitioned into separate (Case 2) or single (Case 3) liquid phases, suggesting that the partitioning of polyol tracers into the aqueous phase in aerosols should not be ignored. The measurement-based effective Henry's law coefficients (KH,em) of polyol tracers were orders of magnitude higher than their predicted values in pure water (KH,wt). Due to the moderate correlations between log⁡(KH,em/KH,wt) and molality of sulfate ions, the gap between KH,em and KH,wt of polyol tracers could not be fully parameterized by the equation defining “salting-in” effects and might be ascribed to mechanisms of reactive uptake, aqueous phase reaction, “like-dissolves-like” principle, etc. These study results also partly reveal the discrepancy between observation and modeling of organic aerosols.