Hind A. Al-Abadleh

This study investigates the influence of fumaric acid on the optical and microphysical properties of aqueous FeCl₃ microdroplets and how aging affects them. This process replicates a pathway for brown carbon (BrC) formation in the atmosphere. The experiment combines a Paul electrodynamic trap (PET), which captures a single particle, and a dual-wavelength cavity ring-down spectroscopy (CRDS) system. Initially, measurements were conducted under controlled humidity cycling, obtaining the particle phase function at a 532 nm wavelength. Retrievals reveal an irreversible increase in particle radius and complex refractive index (m _λ = n _λ + ik·_λ) after a dehydration–hydration cycle. The second part involves measuring a single particle trapped from the FeCl₃ + fumaric acid solution after 24 h in darkness. Instrumental flexibility enabled complementary measurements of the particle phase function at 473, 532, and 660 nm wavelengths and the extinction cross-section (σ_ext,λ) at 405 and 532 nm wavelengths. The most significant result was the retrieval of multiwavelength m _λ, revealing a strong spectral dependence of k _λ, which decreased from 0.014 at 405 nm to 0.000 at 660 mn. Radiative effects were evaluated and compared with other oxidation pathways of fresh biomass tar proxies, highlighting the need for precise BrC characterization in climate models, particularly in the UV range.

The content and multiphase chemistry of iron (Fe) in multicomponent atmospheric aerosols are important to global climate and oceanic models. To date, reported dissolution rates of Fe span orders of magnitude with no quantifiable dependency on the content of basic minerals that coexist with Fe. Here, we report dissolution rates of Fe in simulated dark atmospheric aging of fully characterized multielement particles under acidic conditions (bulk pH 1 or 3) with and without oxalic acid and pyrocatechol. Our main findings are (a) the total amount of Ca and Mg was higher in coal fly ash than in Arizona test dust, (b) Fe dissolution initial rates increased exponentially with %Ca/Al and %Mg/Al below 50%, (c) a reduction in the Fe dissolution initial rate was observed with %Ca/Al higher than 50%, (d) reactive Ca and Mg minerals increased the calculated initial pH at the liquid/solid interface to values higher by only 1.5–2 units than the measured bulk pH, yet interfacial water remained acidic for Fe dissolution to take place, and (e) reactive Ca and Mg minerals enhanced the deprotonation of organics at the interface, aiding in ligand-promoted dissolution of Fe. The impact of these results is discussed within the context of constraining Fe dissolution kinetic models.

Humic‐like substances (HULIS) are a ubiquitous reactive component of atmospheric aerosol. They participate in the formation of secondary organic aerosols via chemical reactions with atmospheric oxidants. Here, we assess the influence of transition metal ions (namely ferric iron, Fe(III)), and nitrate ions () on the heterogeneous reaction of gaseous NO₂ with an aqueous film containing gallic acid (GA) or tannic acid (TA) as proxies for HULIS. Using a vertical wetted wall flow tube technique, the uptake coefficients of gaseous NO₂ on GA and TA increased nonlinearly with increasing [Fe(III)], in dark and under light irradiation. However, the combined effect of both ions, Fe(III) and , led to a substantial decrease in NO₂ uptake in the dark and under simulated near‐UV sunlight irradiation (300 < λ < 400 nm). The lifetime of GA in dilute aqueous phase, which corresponds to cloud water, due to reaction with NO₂ would be 6 hr during both nighttime and daytime. However, the lifetime of GA in aerosol particles which contain both ions, that is, Fe(III) and , would increase to 27 hr during nighttime and 11 days and 6 hr due to light‐induced reaction with NO₂. Also, we observed, using Fourier transform ion cyclotron resonance mass spectrometry, the formation of nitrocatechols compounds (e.g., methyl‐nitrocatechol), which contribute to brown carbon. Compounds with reduced functional groups such as amines were also observed in the presence of iron and nitrate ions in the dark and under irradiation, indicating that Fe(III) and , can influence the kinetics and product distribution in deliquescent aerosol particles.

Atmospheric aerosol effects on ecological and human health remain uncertain due to their highly complex and evolving nature when suspended in air.

Formate (HCOO^-) is the most dominant intermediate identified during carbon dioxide electrochemical reduction (CO₂ER). While previous studies showed that copper (Cu)-based materials that include Cu(0), Cu₂O, and CuO are ideal catalysts for CO₂ER, challenges to scalability stem from low selectivity and undesirable products in the -1.0-1.0 V range. There are few studies on the binding mechanism of intermediates and products for these systems as well as on changes to surface sites upon applying potential. Here, we use an in situ approach to study the redox surface chemistry of formate on Cu thin films deposited on Si wafers using a VeeMAX III spectroelectrochemical (SEC) cell compatible with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Spectra for surface species were collected in real time as a function of applied potential during cyclic voltammetry (CV) experiments. Results showed the reproducibility of CV curves on freshly prepared Cu/Si wafers with relatively high signal-to-noise ATR-FTIR absorbance features of surface species during these electrochemical experiments. The oxidation reaction of HCOO^- to bicarbonate (HCO₃^-) was observed using ATR-FTIR at a voltage of 0.27 V. Samples were then subjected to reduction in the CV, and the aqueous phase products below the detection limit of the SEC-ATR-FTIR were identified using ion chromatography (IC). We report the formation of glycolate (H₃C₂O₃^-) and glyoxylate (HC₂O₃^-) with trace amounts of oxalate (C₂O₄^2-), indicating that C-C coupling reactions proceed in these systems. Changes to the oxidation state of surface Cu were measured using X-ray photoelectron spectroscopy, which showed a reduction in Cu(0) and an increase in Cu(OH)₂, indicating surface oxidation.

Heterogeneous reaction of gas phase NO₂ 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 NO₂ with a solution containing gallic acid (GA) as a proxy of HULIS at pH 5 relevant for moderately acidic aerosol particles. Results showed that the number of detected N-containing organic compounds largely increased from 4 during the NO₂ reaction with GA in the absence of nitrate and iron ions to 55 in the presence of nitrate and iron ions. The N-containing compounds have reduced nitrogen functional groups, namely amines, imines and imides. These results suggest that the number of N-containing compounds is significantly higher in deliquescent aerosol particles due to the influence of relatively higher ionic strength from nitrate ions and complexation/redox reactivity of iron cations compared to that in the dilute aqueous phase representative of cloud, fog, and rain water.

Efforts are ongoing to address inequities in scientific fields. Here, the author provides a critical look at the practice and culture of science with calls to action to broaden participation and recognition of talented members from marginalized groups in the chemical sciences. Efforts are ongoing to address inequities in scientific fields. Here, the author provides a critical look at the practice and culture of science with calls to action to broaden participation and recognition of talented members from marginalized groups in the chemical sciences.

On June 14, 2022, at the Canadian Chemistry Conference and Exhibition in Calgary, Alberta, I delivered the award lecture for the inaugural Canadian Society of Chemistry (CSC) Gilead Award for Excellence in Equity, Diversity, and Inclusion. The lecture was scheduled in a special symposium entitled, “Affecting Institutional Equity, Diversity, and Inclusion (EDI) Mindsets”, organized by Professor Stephanie MacQuarrie, Cape Breton University, Dr. Nimrat Obhi, Beyond Benign, Professor Dipesh Prema, Thompson Rivers University, Dr. Janelle Sauvageau, National Research Council, Dr. Bryony McAllister, Transport Canada, Professor Nola Etkin, University of Prince Edward Island, and Professor Jean-Denys Hamel, University of Lethbridge. Fig. 1 shows photos from the award reception with representatives from Gilead Sciences, the Chemical Institute of Canada (CIC), and the CSC Working towards Inclusion, Diversity, and Equity (WIDE) working group, then committee. This paper is an excerpt of the award lecture with a focus on my 10+ years of contributions to EDI within the Canadian Chemistry Community. Efforts to address equitable access to education and research in chemistry are ongoing in many countries around the world. Here, Professor Hind A. Al-Abadleh provides a personal account of her contributions to equity, diversity, and inclusion in the Canadian chemistry community.