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Reading and understanding scientific literature is an essential skill for any scientist to learn. While students’ scientific literacy can be improved by reading research articles, an article’s technical language and structure can hinder students’ understanding of the scientific material. Furthermore, many students struggle with interpreting graphs and other models of data commonly found in scientific literature. To introduce students to scientific literature and promote improved understanding of data and graphs, we developed a guided-inquiry activity adapted from a research article on snow chemistry and implemented it in a general chemistry laboratory course. Here, we describe how we adapted figures from the primary literature source and developed questions to scaffold the guided-inquiry activity. Results from semi-structured qualitative interviews suggest that students learn about snow chemistry processes and engage in scientific practices, including data analysis and interpretation, through this activity. This activity is applicable in other introductory science courses as educators can adapt most scientific articles into a guided-inquiry activity. 

Anthropogenic and natural emissions contribute to enhanced concentrations of aerosols in the Arctic winter and early spring, with most attention being paid to anthropogenic aerosols that contribute to so-called Arctic haze. Less-well-studied wintertime sea-spray aerosols (SSAs) under Arctic haze conditions are the focus of this study, since they can make an important contribution to wintertime Arctic aerosol abundances. Analysis of field campaign data shows evidence for enhanced local sources of SSAs, including marine organics at Utqiaġvik (formerly known as Barrow) in northern Alaska, United States, during winter 2014. Models tend to underestimate sub-micron SSAs and overestimate super-micron SSAs in the Arctic during winter, including the base version of the Weather Research Forecast coupled with Chemistry (WRF-Chem) model used here, which includes a widely used SSA source function based on Gong et al. (1997). Quasi-hemispheric simulations for winter 2014 including updated wind speed and sea-surface temperature (SST) SSA emission dependencies and sources of marine sea-salt organics and sea-salt sulfate lead to significantly improved model performance compared to observations at remote Arctic sites, notably for coarse-mode sodium and chloride, which are reduced. The improved model also simulates more realistic contributions of SSAs to inorganic aerosols at different sites, ranging from 20 %–93 % in the observations. Two-thirds of the improved model performance is from the inclusion of the dependence on SSTs. The simulation of nitrate aerosols is also improved due to less heterogeneous uptake of nitric acid on SSAs in the coarse mode and related increases in fine-mode nitrate. This highlights the importance of interactions between natural SSAs and inorganic anthropogenic aerosols that contribute to Arctic haze. Simulation of organic aerosols and the fraction of sea-salt sulfate are also improved compared to observations. However, the model underestimates episodes with elevated observed concentrations of SSA components and sub-micron non-sea-salt sulfate at some Arctic sites, notably at Utqiaġvik. Possible reasons are explored in higher-resolution runs over northern Alaska for periods corresponding to the Utqiaġvik field campaign in January and February 2014. The addition of a local source of sea-salt marine organics, based on the campaign data, increases modelled organic aerosols over northern Alaska. However, comparison with previous available data suggests that local natural sources from open leads, as well as local anthropogenic sources, are underestimated in the model. Missing local anthropogenic sources may also explain the low modelled (sub-micron) non-sea-salt sulfate at Utqiaġvik. The introduction of a higher wind speed dependence for sub-micron SSA emissions, also based on Arctic data, reduces biases in modelled sub-micron SSAs, while sea-ice fractions, including open leads, are shown to be an important factor controlling modelled super-micron, rather than sub-micron, SSAs over the north coast of Alaska. The regional results presented here show that modelled SSAs are more sensitive to wind speed dependence but that realistic modelling of sea-ice distributions is needed for the simulation of local SSAs, including marine organics. This study supports findings from the Utqiaġvik field campaign that open leads are the primary source of fresh and aged SSAs, including marine organic aerosols, during wintertime at Utqiaġvik; these findings do not suggest an influence from blowing snow and frost flowers. To improve model simulations of Arctic wintertime aerosols, new field data on processes that influence wintertime SSA production, in particular for fine-mode aerosols, are needed as is improved understanding about possible local anthropogenic sources. 

Abstract. The atmospheric multiphase reaction of dinitrogenpentoxide (N2O5) with chloride-containing aerosol particlesproduces nitryl chloride (ClNO2), which has been observed across theglobe. The photolysis of ClNO2 produces chlorine radicals and nitrogendioxide (NO2), which alter pollutant fates and air quality. However,the effects of local meteorology on near-surface ClNO2 production arenot yet well understood, as most observational and modeling studies focus onperiods of clear conditions. During a field campaign in Kalamazoo, Michigan,from January–February 2018, N2O5 and ClNO2 were measuredusing chemical ionization mass spectrometry, with simultaneous measurementsof atmospheric particulate matter and meteorological parameters. We examinethe impacts of atmospheric turbulence, precipitation (snow, rain) and fog,and ground cover (snow-covered and bare ground) on the abundances ofClNO2 and N2O5. N2O5 mole ratios were lowest duringperiods of lower turbulence and were not statistically significantlydifferent between snow-covered and bare ground. In contrast, ClNO2 moleratios were highest, on average, over snow-covered ground, due to salinesnowpack ClNO2 production. Both N2O5 and ClNO2 moleratios were lowest, on average, during rainfall and fog because ofscavenging, with N2O5 scavenging by fog droplets likelycontributing to observed increased particulate nitrate concentrations. Theseobservations, specifically those during active precipitation and withsnow-covered ground, highlight important processes, including N2O5and ClNO2 wet scavenging, fog nitrate production, and snowpackClNO2 production, that govern the variability in observed atmosphericchlorine and nitrogen chemistry and are missed when considering only clearconditions. 

The ability of atmospheric aerosols to impact climate through water uptake and cloud formation is fundamentally determined by the size, composition, and phase (liquid, semisolid, or solid) of individual particles. Particle phase is dependent on atmospheric conditions (relative humidity and temperature) and chemical composition and, importantly, solid particles can inhibit the uptake of water and other trace gases, even under humid conditions. Particles composed primarily of ammonium sulfate are presumed to be liquid at the relative humidities (67 to 98%) and temperatures (−2 to 4 °C) of the summertime Arctic. Under these atmospheric conditions, we report the observation of solid organic-coated ammonium sulfate particles representing 30% of particles, by number, in a key size range (<0.2 µm) for cloud activation within marine air masses from the Arctic Ocean at Utqiaġvik, AK. The composition and size of the observed particles are consistent with recent Arctic modeling and observational results showing new particle formation and growth from dimethylsulfide oxidation to form sulfuric acid, reaction with ammonia, and condensation of marine biogenic sulfate and highly oxygenated organic molecules. Aqueous sulfate particles typically undergo efflorescence and solidify at relative humidities of less than 34%. Therefore, the observed solid phase is hypothesized to occur from contact efflorescence during collision of a newly formed Aitken mode sulfate particle with an organic-coated ammonium sulfate particle. With declining sea ice in the warming Arctic, this particle source is expected to increase with increasing open water and marine biogenic emissions.