Dominant Contribution of Non-dust Primary Emissions and Secondary Processes to Dissolved Aerosol Iron.

Solubility largely determines the impacts of aerosol Fe on marine ecosystems and human health. Currently, modeling studies have large uncertainties in aerosol Fe solubility due to inadequate understanding of the sources of dissolved Fe. This work investigated seasonal variations of Fe solubility in coarse and fine aerosols in Qingdao, a coastal city in the Northwest Pacific, and utilized a receptor model for source apportionment of total and dissolved aerosol Fe.

Stillbirths Associated with Particle Pollution are Disproportionally Contributed by Sand Dust: Findings from 52 Low- and Middle-Income Countries.

Whether maternal exposure to dust-sourced particulate matter (hereafter, dust PM) is associated with stillbirth remains unknown. We adopted a sibling-matched case-control design to analyze 9332 stillbirths and 17,421 live births. We associated the risk of stillbirth simultaneously with dust and nondust components of PM and developed a nonlinear joint exposure-response function.

A water probe for direct pH measurement of individual particles via micro-Raman spectroscopy.

The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human health. We recently developed a novel and facile water-probe-based method for directly measuring of the pH for micrometer-size droplets, providing a promising technique to better understand aerosol acidity in the atmosphere. The complex chemical composition of fine particles in the ambient air, however, poses certain challenges to using a water-probe for pH measurement, including interference from interactions between compositions and the influence of similar compositions on water structure.

On using an aerosol thermodynamic model to calculate aerosol acidity of coarse particles.

Thermodynamic modeling is still the most widely used method to characterize aerosol acidity, a critical physicochemical property of atmospheric aerosols. However, it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamic models are employed to estimate the acidity of coarse particles. In this work, field measurements were conducted at a coastal city in northern China across three seasons, and covered wide ranges of temperature, relative humidity and NH concentrations.

Toward an Understanding of Uric Acid Particle Dissolution: Surface and Bulk-Driven Water Activity.

Uric acid particles contribute to kidney stones, and natural processes for the elimination of stones depend on solute-solvent interactions. The process of uric acid dissolution has previously been understood via the lens of solubility; however, for pure and mixed salt solutions, these approaches do not provide a comprehensive picture of nanoscale particle solution thermodynamics. Unlike solubility measurements, water activity measurements provide us with information about the chemical potential responsible for the migration of water molecules driving the dissolution of particles.

Burden of Child Anemia Attributable to Fine Particulate Matters Brought by Sand Dusts in Low- and Middle-Income Countries.

Addressing environmental factors has recently been recommended to curb the growing trend of anemia in low- and middle-income countries (LMICs). Fine particulate matter (PM) generated by dust storms were concentrated in place with a high prevalence of anemia. In a multicounty, multicenter study, we analyzed the association between anemia and life-course averaged exposure to dust PM among children aged <5 years based on 0.

Formation of nitrogen-containing gas phase products from the heterogeneous (photo)reaction of NO with gallic acid.

Heterogeneous reaction of gas phase NO with atmospheric humic-like substances (HULIS) is potentially an important source of volatile organic compounds (VOCs) including nitrogen (N)-containing compounds, a class of brown carbon of emerging importance. However, the role of ubiquitous water-soluble aerosol components in this multiphase chemistry, namely nitrate and iron ions, remains largely unexplored. Here, we used secondary electrospray ionization ultrahigh-resolution mass spectrometry for real-time measurements of VOCs formed during the heterogeneous reaction of gas phase NO with a solution containing gallic acid (GA) as a proxy of HULIS at pH 5 relevant for moderately acidic aerosol particles.

Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the "Air Pollution Complex".

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the "air pollution complex" was first proposed by Professor Xiaoyan TANG in 1997. For papers published in 2021 on air pollution (only papers included in the Web of Science Core Collection database were considered), more than 24 000 papers were authored or co-authored by scientists working in China. In this paper, we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years, including studies on (1) sources and emission inventories, (2) atmospheric chemical processes, (3) interactions of air pollution with meteorology, weather and climate, (4) interactions between the biosphere and atmosphere, and (5) data assimilation.

Heterogeneous reaction of NO with feldspar, three clay minerals and Arizona Test Dust.

Heterogeneous reaction of NO with mineral dust aerosol may play important roles in troposphere chemistry, and has been investigated by a number of laboratory studies. However, the influence of mineralogy on this reaction has not been well understood, and its impact on aerosol hygroscopicity is not yet clear. This work investigated heterogeneous reactions of NO (∼10 ppmv) with K-feldspar, illite, kaolinite, montmorillonite and Arizona Test Dust (ATD) at room temperature as a function of relative humidity (<1% to 80%) and reaction time (up to 24 hr).

Effects of heterogeneous reaction with NO on ice nucleation activities of feldspar and Arizona Test Dust.

Mineral dust is an important type of ice nucleating particles in the troposphere; however, the effects of heterogeneous reactions on ice nucleation (IN) activities of mineral dust remain to be elucidated. A droplet-freezing apparatus (Guangzhou Institute of Geochemistry Ice Nucleation Apparatus, GIGINA) was developed in this work to measure IN activities of atmospheric particles in the immersion freezing mode, and its performance was validated by a series of experimental characterizations. This apparatus was then employed to measure IN activities of feldspar and Arizona Test Dust (ATD) particles before and after heterogeneous reaction with NO (10±0.

Mass fractions, solubility, speciation and isotopic compositions of iron in coal and municipal waste fly ash.

Deposition of anthropogenic aerosols may contribute significantly to dissolved Fe in the open ocean, affecting marine primary production and biogeochemical cycles; however, fractional solubility of Fe is not well understood for anthropogenic aerosols. This work investigated mass fractions, solubility, speciation and isotopic compositions of Fe in coal and municipal waste fly ash. Compared to desert dust (3.

Hygroscopicity and cloud condensation nucleation activities of hydroxyalkylsulfonates.

Hydroxyalkylsulfonates may contribute significantly to atmospheric particles; however, their hygroscopic properties and cloud condensation nuclei (CCN) activities remain unknown. In this study, three complementary techniques were utilized to examine the hygroscopicity of sodium hydroxymethanesulfonate (NaHMS), sodium 2-hydroxyethylsulfonate (NaHES), and ammonium 2-hydroxyethylsulfonate (NHHES) under subsaturated and supersaturated environments. The mass changes in the three hydroxyalkylsulfonates at different relative humidities at 25 °C were examined by a vapor sorption analyzer, and the mass growth factors were measured to be 3.

Water as a probe for pH measurement in individual particles using micro-Raman spectroscopy.

Atmospheric aerosol acidity impacts numerous physicochemical processes, but the determination of particle pH remains a significant challenge due to the nonconservative nature of the H concentration ([H]). Traditional measurements have difficulty in describing the practical state of an aerosol because they comprise chemical components or hypotheses that change the nature of the particles. In this work, we present a direct pH measurement that uses water as a general probe to detect [H] in individual particles by micro-Raman spectroscopy.

Abundance and fractional solubility of phosphorus and trace metals in combustion ash and desert dust: Implications for bioavailability and reactivity.

Aerosol phosphorus (P) and trace metals derived from natural processes and anthropogenic emissions have considerable impacts on ocean ecosystems, human health, and atmospheric processes. However, the abundance and fractional solubility of P and trace metals in combustion ash and desert dust, which are two of the largest emission sources of aerosols, are still not well understood. In this study, the abundance and fractional solubility of P and trace metals in seven coal fly ash samples, two municipal waste fly ash samples, and three desert dust samples were experimentally examined.

A review of measurement techniques for aerosol effective density.

Density (ρ) is one of the most important physical properties of aerosol particles. Owing to the complex nature of aerosols and the challenges of measuring them, effective density (ρ) is generally used as an alternative measure. Various methods have been developed to quantify the ρ of aerosols, which provide powerful technical support and understanding of their physical properties.

Hygroscopic properties of sodium and potassium salts as related to saline mineral dusts and sea salt aerosols.

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction.

Effects of NH and alkaline metals on the formation of particulate sulfate and nitrate in wintertime Beijing.

Sulfate and nitrate from secondary reactions remain as the most abundant inorganic species in atmospheric particle matter (PM). Their formation is initiated by oxidation (either in gas phase or particle phase), followed by neutralization reaction primarily by NH, or by other alkaline species such as alkaline metal ions if available. The different roles of NH and metal ions in neutralizing HSO or HNO, however, are seldom investigated.

Heterogeneous reaction of NO with hematite, goethite and magnetite: Implications for nitrate formation and iron solubility enhancement.

Atmospheric processing may significantly increase solubility of iron in mineral dust, but the effects of heterogeneous reactions on iron solubility have been poorly understood. In this work, we investigated heterogeneous reaction of NO (15 ± 1 and 2.5 ± 0.

Primary emissions and secondary organic aerosol formation from in-use diesel vehicle exhaust: Comparison between idling and cruise mode.

Diesel vehicle exhaust is an important source of carbonaceous aerosols, especially in developing countries, like China. Driving condition impacts diesel vehicle emissions, yet its influence needs further understanding especially on secondary organic aerosol (SOA) formation. In this study tailpipe exhaust from an in-use light duty diesel vehicle at idling and driving speeds of 20 and 40 km h was introduced respectively into a 30 m indoor smog chamber to investigate primary emissions and SOA formation during photo-oxidation.

Aerosol Phase State and Its Link to Chemical Composition and Liquid Water Content in a Subtropical Coastal Megacity.

Particle phase state plays a key role in gas-particle partitioning, heterogeneous and multiphase reactions, and secondary aerosol formation. In this work, the rebound fraction and chemical composition of submicron particles were simultaneously measured to investigate the particle phase state and its link to chemical composition in a subtropical coastal urban city (Shenzhen, China). Submicron particles were found to be in the liquid state for most of the measurement period in spring.

Mannich Base as Corrosion Inhibitors for N80 Steel in a CO₂ Saturated Solution Containing 3 wt % NaCl.

In this paper, a corrosion inhibitor containing nitrogen atoms and a conjugated π bond was synthesised, and its final product synthesised by the optimal conditions of the orthogonal test results is named multi-mannich base (MBT). The corrosion inhibition effect on the N80 steel sheet of the corrosion inhibitor was evaluated in a CO₂ saturated solution containing 3 wt % NaCl; the corrosion rate was 0.0446 mm/a and the corrosion inhibition rate was 90.

Oxalate Formation Enhanced by Fe-Containing Particles and Environmental Implications.

We used a single particle mass spectrometry to online detect chemical compositions of individual particles over four seasons in Guangzhou. Number fractions (Nfs) of all the measured particles that contained oxalate were 1.9%, 5.