Closure between aerosol particles and cloud condensation nuclei at Kaashidhoo Climate Observatory

Predicting the cloud condensation nuclei (CCN) supersaturation spectrum from aerosol properties is a fairly straightforward matter, as long as those properties are simple. During the Indian Ocean Experiment we measured CCN spectra, size-resolved aerosol chemical composition, and aerosol number distributions and attempted to reconcile them using a modified form of Köhler theory. We obtained general agreement between our measured and modeled CCN spectra. However, the agreement was not as good during a time period when organic carbon comprised a quarter of the total mass of the aerosol in the submicron size range. The modeled concentrations overpredict those actually measured during that time period. This suggests that some component, presumably organic material, can inhibit the uptake of water by the electrolytic fraction of the mass

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Direct Night-Time Ejection of Particle-Phase Reduced Biogenic Sulfur Compounds from the Ocean to the Atmosphere

The influence of oceanic biological activity on sea spray aerosol composition, clouds, and climate remains poorly understood. The emission of organic material and gaseous dimethyl sulfide (DMS) from the ocean represents well-documented biogenic processes that influence particle chemistry in marine environments. However, the direct emission of particle-phase biogenic sulfur from the ocean remains largely unexplored. Here we present measurements of ocean-derived particles containing reduced sulfur, detected as elemental sulfur ions (e.g., ³²S⁺, ⁶⁴S₂⁺), in seven different marine environments using <i>real-time</i>, single particle mass spectrometry; these particles have not been detected outside of the marine environment. These reduced sulfur compounds were associated with primary marine particle types and wind speeds typically between 5 and 10 m/s suggesting that these particles themselves are a primary emission. In studies with measurements of seawater properties, chlorophyll-<i>a</i> and atmospheric DMS concentrations were typically elevated in these same locations suggesting a biogenic source for these sulfur-containing particles. Interestingly, these sulfur-containing particles only appeared at night, likely due to rapid photochemical destruction during the daytime, and comprised up to ∼67% of the aerosol number fraction, particularly in the supermicrometer size range. These sulfur-containing particles were detected along the California coast, across the Pacific Ocean, and in the southern Indian Ocean suggesting that these particles represent a globally significant biogenic contribution to the marine aerosol burden

Unique ocean-derived particles serve as a proxy for changes in ocean chemistry

Oceans represent a significant natural source of gases and particles to the atmosphere.Relative to gas phase compounds, less is known regarding the influence of changes inbiological activity in the ocean on the chemistry of sea spray aerosols produced in marineenvironments. To gain insight into the influence of ocean biology and chemistry onatmospheric aerosol chemistry, simultaneous real‐time measurements were made ofatmospheric aerosol size and chemical mixing‐state, gas phase dimethyl sulfide (DMS), aswell as seawater DMS and chlorophyll a. In three different marine environments withelevated chlorophyll a and DMS, unique Mg particles were detected containing Mg2+,Ca2+, K+, and organic carbon. These particles were segregated from sea salt particleshighlighting that two subpopulations within the sea spray were being ejected from theocean. Strong temporal correlations were observed between these unique ocean‐derivedparticles and freshly emitted sea salt particles (R2= 0.86), particularly as wind speedincreased to at least 10 m/s, and atmospheric DMS (R2= 0.76). Time series correlationsbetween ocean measurements and atmospheric aerosol chemistry suggest that chlorophyll aand DMS serve as indicators of changes in the chemistry of the ocean, most likely anincrease in organic material, which is directly reflected in the single particle mixing‐state.This is the first time such real‐time correlations are shown between ocean chemistryand atmospheric aerosol mixing‐state. The reasons behind these observed changes inaerosol chemistry are critical for understanding the heterogeneous reactivity, wateruptake, and cloud forming potential of sea spray aerosols

Marine boundary layer dust and pollutant transport associated with the passage of a frontal system over eastern Asia

Aerosol chemical composition and number size distributions were measured aboard the R/V Ronald H. Brown during the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) from 14 March to 20 April 2001. This manuscript focuses on the prefrontal and postfrontal air masses sampled aboard the ship in the Sea of Japan between 6 and 15 April 2001 to illustrate the different chemical sources/mixtures off the coast of Asia resulting from the contrasting meteorological transport patterns. The prefrontal air masses had a dominant accumulation mode composed of pollution and volcanic aerosols. The aerosol was predominately ammonium sulfate and organic carbon. Minor amounts of dust were present in the marine boundary layer (MBL) as a result of subsidence from a pronounced Taklimakan dust aerosol layer aloft. The sea salt in both the submicron and supermicron modes was highly depleted in chloride from reaction with sulfuric and nitric acid vapors. The passage of a large low-pressure center, surrounded by a widespread distribution of airborne dust, on 10 April brought elevated concentrations of submicron and supermicron Gobi desert dust to the ship. The supermicron dust particles contained high concentrations of sulfate, nitrate, organic, and elemental carbon. The MBL aerosol properties and controlling processes described here provide data to evaluate and refine chemical transport models. Copyright 2004 by the American Geophysical Union