Temperature, humidity, and ionisation effect of iodine oxoacid nucleation.

Iodine oxoacids are recognised for their significant contribution to the formation of new particles in marine and polar atmospheres. Nevertheless, to incorporate the iodine oxoacid nucleation mechanism into global simulations, it is essential to comprehend how this mechanism varies under various atmospheric conditions. In this study, we combined measurements from the CLOUD (Cosmic Leaving OUtdoor Droplets) chamber at CERN and simulations with a kinetic model to investigate the impact of temperature, ionisation, and humidity on iodine oxoacid nucleation. Our findings reveal that ion-induced particle formation rates remain largely unaffected by changes in temperature. However, neutral particle formation rates experience a significant increase when the temperature drops from +10 °C to -10 °C. Running the kinetic model with varying ionisation rates demonstrates that the particle formation rate only increases with a higher ionisation rate when the iodic acid concentration exceeds 1.5 × 107 cm-3, a concentration rarely reached in pristine marine atmospheres. Consequently, our simulations suggest that, despite higher ionisation rates, the charged cluster nucleation pathway of iodic acid is unlikely to be enhanced in the upper troposphere by higher ionisation rates. Instead, the neutral nucleation channel is likely to be the dominant channel in that region. Notably, the iodine oxoacid nucleation mechanism remains unaffected by changes in relative humidity from 2% to 80%. However, under unrealistically dry conditions (below 0.008% RH at +10 °C), iodine oxides (I2O4 and I2O5) significantly enhance formation rates. Therefore, we conclude that iodine oxoacid nucleation is the dominant nucleation mechanism for iodine nucleation in the marine and polar boundary layer atmosphere.

Assessing the importance of nitric acid and ammonia for particle growth in the polluted boundary layer.

Aerosols formed and grown by gas-to-particle processes are a major contributor to smog and haze in megacities, despite the competition between growth and loss rates. Rapid growth rates from ammonium nitrate formation have the potential to sustain particle number in typical urban polluted conditions. This process requires supersaturation of gas-phase ammonia and nitric acid with respect to ammonium nitrate saturation ratios. Urban environments are inhomogeneous. In the troposphere, vertical mixing is fast, and aerosols may experience rapidly changing temperatures. In areas close to sources of pollution, gas-phase concentrations can also be highly variable. In this work we present results from nucleation experiments at -10 °C and 5 °C in the CLOUD chamber at CERN. We verify, using a kinetic model, how long supersaturation is likely to be sustained under urban conditions with temperature and concentration inhomogeneities, and the impact it may have on the particle size distribution. We show that rapid and strong temperature changes of 1 °C min-1 are needed to cause rapid growth of nanoparticles through ammonium nitrate formation. Furthermore, inhomogeneous emissions of ammonia in cities may also cause rapid growth of particles.

Elevated Anti-Müllerian Hormone as a Prognostic Factor for Poor Outcomes of In Vitro Fertilization in Women with Polycystic Ovary Syndrome.

Women with polycystic ovary syndrome (PCOS) tend to have elevated anti-Müllerian hormone (AMH) levels, which appear to correlate with disease severity and pregnancy outcomes. This was a retrospective observational study designed to assess the relationship between circulating AMH levels and in vitro fertilization (IVF) outcomes. The study involved 150 women with PCOS who underwent IVF treatments. The women's IVF cycles were allocated into three subgroups according to AMH levels: 'low' (AMH < 3.7 ng/mL; n = 49), 'middle' (AMH 3.7-7.4 ng/mL; n = 94), and 'high' (AMH > 7.4 ng/mL; n = 56). All pregnancy-related outcomes (positive beta human chorionic gonadotropin (ßHCG), clinical pregnancy rate, live birth rate, and cumulative live birth rate) were greater in women's IVF cycles with 'low' AMH when compared to those with 'middle' or 'high' AMH (p < 0.05). AMH levels below 3.7 ng/mL were found to be associated with lower oocyte immaturity rate and better pregnancy outcomes, although baseline AMH was not shown to have any significant predictive power for live birth and cumulative live birth in the multivariable logistic regression analysis after adjusting for possible confounders nor in the ROC analyses. In summary, the current study lays the groundwork to validate high AMH levels as a poor prognostic factor for pregnancy outcomes after IVF in women with PCOS.

Female Reproductive Health - study of an egg donor population.

OBJECTIVE: Infertility is one of the most significant reproductive health issues addressed with medically assisted procreation. This study looked into a potential correlation between the number of mature oocytes harvested and donor biological characteristics in order to propose an anti-Müllerian hormone (AMH) cutoff level to optimize the selection of candidates for gamete donation. METHODS: The donors were healthy women included in the Public Gamete Bank between 2011 and 2021. Their results can be used as a national indicator of fertility. RESULTS: We found that women with higher AMH levels had more antral follicles and oocytes harvested. As age increased, the number of oocytes harvested decreased. The suggested AMH cutoff level for successful donation was 1.12 ng/mL. CONCLUSIONS: The analysis of the reproductive health of Public Gamete Bank donors allows the standardization of AMH cutoff values at a national level, since the same laboratory techniques were employed consistently across medical centers. The study also allowed insight into the factors that compromise donation success. If adopted, a more rigorous selection of donor candidates would increase the success rate of egg donations.

Role of sesquiterpenes in biogenic new particle formation.

Biogenic vapors form new particles in the atmosphere, affecting global climate. The contributions of monoterpenes and isoprene to new particle formation (NPF) have been extensively studied. However, sesquiterpenes have received little attention despite a potentially important role due to their high molecular weight. Via chamber experiments performed under atmospheric conditions, we report biogenic NPF resulting from the oxidation of pure mixtures of ß-caryophyllene, α-pinene, and isoprene, which produces oxygenated compounds over a wide range of volatilities. We find that a class of vapors termed ultralow-volatility organic compounds (ULVOCs) are highly efficient nucleators and quantitatively determine NPF efficiency. When compared with a mixture of isoprene and monoterpene alone, adding only 2% sesquiterpene increases the ULVOC yield and doubles the formation rate. Thus, sesquiterpene emissions need to be included in assessments of global aerosol concentrations in pristine climates where biogenic NPF is expected to be a major source of cloud condensation nuclei.

NO at low concentration can enhance the formation of highly oxygenated biogenic molecules in the atmosphere.

The interaction between nitrogen monoxide (NO) and organic peroxy radicals (RO2) greatly impacts the formation of highly oxygenated organic molecules (HOM), the key precursors of secondary organic aerosols. It has been thought that HOM production can be significantly suppressed by NO even at low concentrations. Here, we perform dedicated experiments focusing on HOM formation from monoterpenes at low NO concentrations (0 - 82 pptv). We demonstrate that such low NO can enhance HOM production by modulating the RO2 loss and favoring the formation of alkoxy radicals that can continue to autoxidize through isomerization. These insights suggest that HOM yields from typical boreal forest emissions can vary between 2.5%-6.5%, and HOM formation will not be completely inhibited even at high NO concentrations. Our findings challenge the notion that NO monotonically reduces HOM yields by extending the knowledge of RO2-NO interactions to the low-NO regime. This represents a major advance towards an accurate assessment of HOM budgets, especially in low-NO environments, which prevails in the pre-industrial atmosphere, pristine areas, and the upper boundary layer.

The gas-phase formation mechanism of iodic acid as an atmospheric aerosol source.

Iodine is a reactive trace element in atmospheric chemistry that destroys ozone and nucleates particles. Iodine emissions have tripled since 1950 and are projected to keep increasing with rising O3 surface concentrations. Although iodic acid (HIO3) is widespread and forms particles more efficiently than sulfuric acid, its gas-phase formation mechanism remains unresolved. Here, in CLOUD atmospheric simulation chamber experiments that generate iodine radicals at atmospherically relevant rates, we show that iodooxy hypoiodite, IOIO, is efficiently converted into HIO3 via reactions (R1) IOIO + O3 → IOIO4 and (R2) IOIO4 + H2O → HIO3 + HOI + (1)O2. The laboratory-derived reaction rate coefficients are corroborated by theory and shown to explain field observations of daytime HIO3 in the remote lower free troposphere. The mechanism provides a missing link between iodine sources and particle formation. Because particulate iodate is readily reduced, recycling iodine back into the gas phase, our results suggest a catalytic role of iodine in aerosol formation.

High Gas-Phase Methanesulfonic Acid Production in the OH-Initiated Oxidation of Dimethyl Sulfide at Low Temperatures.

Dimethyl sulfide (DMS) influences climate via cloud condensation nuclei (CCN) formation resulting from its oxidation products (mainly methanesulfonic acid, MSA, and sulfuric acid, H2SO4). Despite their importance, accurate prediction of MSA and H2SO4 from DMS oxidation remains challenging. With comprehensive experiments carried out in the Cosmics Leaving Outdoor Droplets (CLOUD) chamber at CERN, we show that decreasing the temperature from +25 to -10 °C enhances the gas-phase MSA production by an order of magnitude from OH-initiated DMS oxidation, while H2SO4 production is modestly affected. This leads to a gas-phase H2SO4-to-MSA ratio (H2SO4/MSA) smaller than one at low temperatures, consistent with field observations in polar regions. With an updated DMS oxidation mechanism, we find that methanesulfinic acid, CH3S(O)OH, MSIA, forms large amounts of MSA. Overall, our results reveal that MSA yields are a factor of 2-10 higher than those predicted by the widely used Master Chemical Mechanism (MCMv3.3.1), and the NOx effect is less significant than that of temperature. Our updated mechanism explains the high MSA production rates observed in field observations, especially at low temperatures, thus, substantiating the greater importance of MSA in the natural sulfur cycle and natural CCN formation. Our mechanism will improve the interpretation of present-day and historical gas-phase H2SO4/MSA measurements.

Survival of newly formed particles in haze conditions.

Intense new particle formation events are regularly observed under highly polluted conditions, despite the high loss rates of nucleated clusters. Higher than expected cluster survival probability implies either ineffective scavenging by pre-existing particles or missing growth mechanisms. Here we present experiments performed in the CLOUD chamber at CERN showing particle formation from a mixture of anthropogenic vapours, under condensation sinks typical of haze conditions, up to 0.1 s-1. We find that new particle formation rates substantially decrease at higher concentrations of pre-existing particles, demonstrating experimentally for the first time that molecular clusters are efficiently scavenged by larger sized particles. Additionally, we demonstrate that in the presence of supersaturated gas-phase nitric acid (HNO3) and ammonia (NH3), freshly nucleated particles can grow extremely rapidly, maintaining a high particle number concentration, even in the presence of a high condensation sink. Such high growth rates may explain the high survival probability of freshly formed particles under haze conditions. We identify under what typical urban conditions HNO3 and NH3 can be expected to contribute to particle survival during haze.

Male Reproductive Health - study of a sperm donor population.

OBJECTIVE: Every individual has the right to a safe and satisfactory sex and reproductive life. Therefore, several countries have made efforts to make Reproductive Health resources available to their populations. However, few results have been published regarding the policies implemented in Portugal. This study looked into the reproductive health status of the Portuguese male population. METHODS: Sperm donor candidates from the Portuguese Public Gamete Bank registered between 2011 and 2018 were included in the study. Spermogram findings were evaluated with respect to sociodemographic and risk factors. RESULTS: This is the first study performed in this population. We found that sperm quality has decreased throughout the last nine years, and that spermatozoa progressive motility is inversely correlated with the body mass index. An association between drug use and decreased sperm pH was also found. CONCLUSIONS: Changes in sperm quality have important consequences in male fertility. Most of the identified causes of decreased sperm quality are modifiable factors and should therefore be addressed since an early age.

Molecular characterization of ultrafine particles using extractive electrospray time-of-flight mass spectrometry.

Aerosol particles negatively affect human health while also having climatic relevance due to, for example, their ability to act as cloud condensation nuclei. Ultrafine particles (diameter D p < 100 nm) typically comprise the largest fraction of the total number concentration, however, their chemical characterization is difficult because of their low mass. Using an extractive electrospray time-of-flight mass spectrometer (EESI-TOF), we characterize the molecular composition of freshly nucleated particles from naphthalene and ß-caryophyllene oxidation products at the CLOUD chamber at CERN. We perform a detailed intercomparison of the organic aerosol chemical composition measured by the EESI-TOF and an iodide adduct chemical ionization mass spectrometer equipped with a filter inlet for gases and aerosols (FIGAERO-I-CIMS). We also use an aerosol growth model based on the condensation of organic vapors to show that the chemical composition measured by the EESI-TOF is consistent with the expected condensed oxidation products. This agreement could be further improved by constraining the EESI-TOF compound-specific sensitivity or considering condensed-phase processes. Our results show that the EESI-TOF can obtain the chemical composition of particles as small as 20 nm in diameter with mass loadings as low as hundreds of ng m-3 in real time. This was until now difficult to achieve, as other online instruments are often limited by size cutoffs, ionization/thermal fragmentation and/or semi-continuous sampling. Using real-time simultaneous gas- and particle-phase data, we discuss the condensation of naphthalene oxidation products on a molecular level.

Photo-oxidation of Aromatic Hydrocarbons Produces Low-Volatility Organic Compounds.

To better understand the role of aromatic hydrocarbons in new-particle formation, we measured the particle-phase abundance and volatility of oxidation products following the reaction of aromatic hydrocarbons with OH radicals. For this we used thermal desorption in an iodide-adduct Time-of-Flight Chemical-Ionization Mass Spectrometer equipped with a Filter Inlet for Gases and AEROsols (FIGAERO-ToF-CIMS). The particle-phase volatility measurements confirm that oxidation products of toluene and naphthalene can contribute to the initial growth of newly formed particles. Toluene-derived (C7) oxidation products have a similar volatility distribution to that of α-pinene-derived (C10) oxidation products, while naphthalene-derived (C10) oxidation products are much less volatile than those from toluene or α-pinene; they are thus stronger contributors to growth. Rapid progression through multiple generations of oxidation is more pronounced in toluene and naphthalene than in α-pinene, resulting in more oxidation but also favoring functional groups with much lower volatility per added oxygen atom, such as hydroxyl and carboxylic groups instead of hydroperoxide groups. Under conditions typical of polluted urban settings, naphthalene may well contribute to nucleation and the growth of the smallest particles, whereas the more abundant alkyl benzenes may overtake naphthalene once the particles have grown beyond the point where the Kelvin effect strongly influences the condensation driving force.

Adnexal Torsion in the First Trimester of Pregnancy: Diagnosis, Laparoscopic Management, and Review of the Literature.

We report a case of an adnexal torsion in a 27-year-old woman in her 12th week of gestation. She presented with hypogastric and lumbar pain with biliary vomiting and nausea. Upon physical examination, tenderness in the right lower quadrant with rebound tenderness was apparent, and gynecological examination revealed right adnexal tenderness with absence of abnormal cervical discharge. The transvaginal ultrasonography demonstrated an enlarged cystic right ovary with no flow detected on color and power Doppler mode. We performed a laparoscopy and the diagnosis of adnexal torsion was confirmed. Detorsion of the right adnexa and cystectomy of the ovary was achieved without surgical or anesthetic complications. The patient was supplemented with progesterone during pregnancy and gave birth to a healthy child at term. Adnexal torsion is an unusual cause of abdominal pain in gestation with an incidence of 1-5:10.000, and it is more often observed during the first and early second trimesters of gestation. The clinical signs are often unspecific, and an ultrasound is the most commonly used imaging method for this diagnosis. The laparoscopy is the preferred method of diagnosis and treatment can be safely used in pregnancy if the guidelines are respected.

Minilaparoscopic Versus Conventional Laparoscopic Sacrocolpopexy: A Comparative Study.

INTRODUCTION AND AIMS: We aim to compare clinical and surgical outcomes between minilaparoscopic sacrocolpopexy (MLSC) and conventional laparoscopic sacrocolpopexy (LSC). As far as we know, no comparative study exists between these two minimal invasive procedures to correct vaginal prolapse. DESIGN AND SETTING: An observational and comparative study with 20 individuals submitted to vaginal vault prolapse correction between June and December of 2014 in our tertiary referral unit. Nine women were submitted to 3-mm MLSC and the others were approached by a standard 5-mm laparoscopic technique. MATERIALS AND METHODS: Women's demographic data and prolapse grade were evaluated preoperatively using the Pelvic Organ Prolapse Quantification score. Operative parameters (surgical time, blood loss, and complications under Satava and Clavien-Dindo classification) and length of hospitalization were also compared. Postoperative pain and surgical scar satisfaction were measured using Visual Analog Pain Scale and Patient and Observer Scar Assessment Questionnaire, respectively. RESULTS: MLSC took approximately the same time as LSC (P > .05). No significant differences in operative time, blood loss, length of hospitalization, and complications (Satava, Clavien-Dindo) were observed between both groups. Pain score after surgery was similar in MLSC and LSC (P > .05). Surgical scar monitoring at 3 months established that MLSC produced better overall results than LSC (P < .05). Anatomic cure rate was 100%. CONCLUSION: Minilaparoscopy is a feasible and attractive approach for sacrocolpopexy as it enhances cosmetics, keeping the low morbidity associated with the classical laparoscopic approaches.

Comparison of the SAWNUC model with CLOUD measurements of sulphuric acid-water nucleation.

Binary nucleation of sulphuric acid-water particles is expected to be an important process in the free troposphere at low temperatures. SAWNUC (Sulphuric Acid Water Nucleation) is a model of binary nucleation that is based on laboratory measurements of the binding energies of sulphuric acid and water in charged and neutral clusters. Predictions of SAWNUC are compared for the first time comprehensively with experimental binary nucleation data from the CLOUD chamber at European Organization for Nuclear Research. The experimental measurements span a temperature range of 208-292 K, sulphuric acid concentrations from 1·106 to 1·109 cm-3, and distinguish between ion-induced and neutral nucleation. Good agreement, within a factor of 5, is found between the experimental and modeled formation rates for ion-induced nucleation at 278 K and below and for neutral nucleation at 208 and 223 K. Differences at warm temperatures are attributed to ammonia contamination which was indicated by the presence of ammonia-sulphuric acid clusters, detected by an Atmospheric Pressure Interface Time of Flight (APi-TOF) mass spectrometer. APi-TOF measurements of the sulphuric acid ion cluster distributions ( (H2SO4)i·HSO4- with i = 0, 1, ..., 10) show qualitative agreement with the SAWNUC ion cluster distributions. Remaining differences between the measured and modeled distributions are most likely due to fragmentation in the APi-TOF. The CLOUD results are in good agreement with previously measured cluster binding energies and show the SAWNUC model to be a good representation of ion-induced and neutral binary nucleation of sulphuric acid-water clusters in the middle and upper troposphere.

Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision.

Neutral molecular cluster formation of sulfuric acid-dimethylamine observed in real time under atmospheric conditions.

For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the lack of suitable instrumentation. Here we report on experiments from the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research revealing the formation of neutral particles containing up to 14 SA and 16 DMA molecules, corresponding to a mobility diameter of about 2 nm, under atmospherically relevant conditions. These measurements bridge the gap between the molecular and particle perspectives of nucleation, revealing the fundamental processes involved in particle formation and growth. The neutral clusters are found to form at or close to the kinetic limit where particle formation is limited only by the collision rate of SA molecules. Even though the neutral particles are stable against evaporation from the SA dimer onward, the formation rates of particles at 1.7-nm size, which contain about 10 SA molecules, are up to 4 orders of magnitude smaller compared with those of the dimer due to coagulation and wall loss of particles before they reach 1.7 nm in diameter. This demonstrates that neither the atmospheric particle formation rate nor its dependence on SA can simply be interpreted in terms of cluster evaporation or the molecular composition of a critical nucleus.

Oxidation products of biogenic emissions contribute to nucleation of atmospheric particles.

Atmospheric new-particle formation affects climate and is one of the least understood atmospheric aerosol processes. The complexity and variability of the atmosphere has hindered elucidation of the fundamental mechanism of new-particle formation from gaseous precursors. We show, in experiments performed with the CLOUD (Cosmics Leaving Outdoor Droplets) chamber at CERN, that sulfuric acid and oxidized organic vapors at atmospheric concentrations reproduce particle nucleation rates observed in the lower atmosphere. The experiments reveal a nucleation mechanism involving the formation of clusters containing sulfuric acid and oxidized organic molecules from the very first step. Inclusion of this mechanism in a global aerosol model yields a photochemically and biologically driven seasonal cycle of particle concentrations in the continental boundary layer, in good agreement with observations.

Cardiovascular risk profile of young adults: changes over time.

BACKGROUND AND OBJECTIVE: The high prevalence and natural history of atherosclerosis make young people important targets for cardiovascular prevention. This study aimed to analyze changes over time in the cardiovascular risk profile of a population of healthy young adults. METHODS: We studied 923 Portuguese Air Force applicants between 1991 and 2007, divided into two-year periods. In addition to cardiovascular risk factors, the Framingham score and HeartScore were calculated for age 65. Cochran-Armitage and Jonckheere-Terpstra tests for trend were used for categorical and continuous variables, respectively. RESULTS: Mean age was 19.2 ± 2.3 years (p = 0.34) and 55 applicants (6%) were female (p = 0.56). Mean body mass index was 22.4 ± 2.5 kg (p for trend 0.35). The number of smokers decreased over the study period (11.6 vs. 7.0%, p for trend 0.02). Of the total number of applicants, 122 (13.2%) were classified as hypertensive. Mean systolic blood pressure was 127 ± 12 mmHg and increased significantly over time (122 ± 13 vs. 128 ± 11 mmHg, p for trend <0.001). Hypercholesterolemia was found in 108 applicants (11.7%) and total cholesterol showed an improvement (170 ± 35 vs. 155 ± 26 mg/dl, p for trend <0.001). The mean modified Framingham score was 12.6 ± 5.1 and improved over the study period (12.9 ± 5.9% vs. 11.9 ± 4.7%, p for trend 0.006). The mean modified HeartScore was 3.2 ± 1.4 and remained unchanged (p for trend 0.10). CONCLUSIONS: In our population, except for an increase in systolic blood pressure values, there was an overall improvement in cardiovascular risk from 1991 to 2007. Further studies are needed to better assess the situation in Portugal and help devise preventive strategies in young people.

Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules.

Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. Here, we present high-resolution mass spectra of ion clusters observed during new particle formation experiments performed at the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research. The experiments involved sulfuric acid vapor and different stabilizing species, including ammonia and dimethylamine, as well as oxidation products of pinanediol, a surrogate for organic vapors formed from monoterpenes. A striking resemblance is revealed between the mass spectra from the chamber experiments with oxidized organics and ambient data obtained during new particle formation events at the Hyytiälä boreal forest research station. We observe that large oxidized organic compounds, arising from the oxidation of monoterpenes, cluster directly with single sulfuric acid molecules and then form growing clusters of one to three sulfuric acid molecules plus one to four oxidized organics. Most of these organic compounds retain 10 carbon atoms, and some of them are remarkably highly oxidized (oxygen-to-carbon ratios up to 1.2). The average degree of oxygenation of the organic compounds decreases while the clusters are growing. Our measurements therefore connect oxidized organics directly, and in detail, with the very first steps of new particle formation and their growth between 1 and 2 nm in a controlled environment. Thus, they confirm that oxidized organics are involved in both the formation and growth of particles under ambient conditions.