Study on the evaluation method of cigarette astringency in the simulated oral environment.

Cigarettes with pronounced astringency can diminish consumers' enjoyment. However, due to the complex composition of cigarettes, quantifying astringency intensity accurately has been challenging. To address this, research was conducted to develop a method for assessing astringency intensity in a simulated oral environment. The astringency intensity of four cigarette brands was determined using the standard sensory evaluation method. The mainstream smoke absorbing solution (MS) was prepared by simulating the cigarette smoking process, and its physicochemical properties (such as total phenol content and pH levels) were analyzed. The lubrication properties of the five solutions were tested using the MFT-5000 wear tester, and factors influencing cigarette astringency were examined. The findings showed that total phenol content and pH of MS were positively and negatively correlated with astringency intensity, respectively. Particularly, the lubrication properties of MS were significantly correlated with astringency intensity, and the correlation coefficient was affected by load and speed during testing. The study concluded that coefficient of friction was a more reliable measure for assessing the extent of astringency in cigarettes than the total phenol content and pH of MS, offering new insights into astringency evaluation and development of high-grade cigarettes.

Photochemical evolution of the molecular composition of dissolved organic carbon and dissolved brown carbon from wood smoldering.

Recently, extreme wildfires occur frequently around the world and emit substantial brown carbon (BrC) into the atmosphere, whereas the molecular compositions and photochemical evolution of BrC remain poorly understood. In this work, primary smoke aerosols were generated from wood smoldering, and secondary smoke aerosols were formed by the OH radical photooxidation in an oxidation flow reactor, where both primary and secondary smoke samples were collected on filters. After solvent extraction of filter samples, the molecular composition of dissolved organic carbon (DOC) was determined by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). The molecular composition of dissolved BrC was obtained based on the constraints of DOC formulae. The proportion of dissolved BrC fractions accounted for approximately 1/3-1/2 molecular formulae of DOC. The molecular characteristics of dissolved BrC showed higher levels of carbon oxidation state, double bond equivalents, and modified aromaticity index than those of DOC, indicating that dissolved BrC fractions were a class of organic structures with relatively higher oxidation state, unsaturated and aromatic degree in DOC fractions. The comparative analysis suggested that aliphatic and olefinic structures dominated DOC fractions (contributing to 70.1%-76.9%), while olefinic, aromatic, and condensed aromatic structures dominated dissolved BrC fractions (contributing to 97.5%-99.9%). It is worth noting that dissolved BrC fractions only contained carboxylic-rich alicyclic molecules (CRAMs)-like structures, unsaturated hydrocarbons, aromatic structures, and highly oxygenated compounds. CRAMs-like structures were the most abundant species in both DOC and dissolved BrC fractions. Nevertheless, the specific molecular characteristics for DOC and dissolved BrC fractions varied with subgroups after aging. The results highlight the similarities and differences in the molecular compositions and characteristics of DOC and dissolved BrC fractions with aging. This work will provide insights into understanding the molecular composition of DOC and dissolved BrC in smoke.

Identification and quantification of flavor compounds in smoked tuna fish based on GC-Orbitrap volatolomics approach.

Cold smoking enhances the appeal of fish products, offering consumers a smooth texture and a delicate smoky flavor. This study aims to explore variations in the volatile profile from different exposure times during cold smoking processing (light, moderate, and full-cure) in tune samples. An innovative untargeted analytical approach, headspace solid-phase microextraction combined with gas chromatography and a hybrid quadrupole-orbitrap mass analyzer, was employed to identify 86 volatiles associated with the cold smoking process. Most of these compounds, including phenols, furan derivates, aldehydes, cyclic ketones, and different aromatic species, were found to contribute to the smoke odor. The development of a QuEChERS-based extraction and clean-up method facilitated the quantification of 25 relevant smoky markers across all smoking degrees, revealing significant concentration differences after 15 h of smoking. This research sheds light on the dynamics of cold smoking impact and its on the flavor profile and safety quality of processed fish products.

Toxic Potencies of Particulate Matter from Typical Industrial Plants Mediated with Acidity via Metal Dissolution.

Acidity is an important property of particulate matter (PM) in the atmosphere, but its association with PM toxicity remains unclear. Here, this study quantitively reports the effect of the acidity level on PM toxicity via pH-control experiments and cellular analysis. Oxidative stress and cytotoxicity potencies of acidified PM samples at pH of 1-2 were up to 2.8-5.2 and 2.1-13.2 times higher than those at pH of 8-11, respectively. The toxic potencies of PM samples from real-world smoke plumes at the pH of 2.3 were 9.1-18.2 times greater than those at the pH of 5.6, demonstrating a trend similar to that of acidified PM samples. Furthermore, the impact of acidity on PM toxicity was manifested by promoting metal dissolution. The dramatic increase by 2-3 orders of magnitude in water-soluble metal content dominated the variation in PM toxicity. The significant correlation between sulfate, the pH value, water-soluble Fe, IC20, and EC1.5 (p < 0.05) suggested that acidic sulfate could enhance toxic potencies by dissolving insoluble metals. The findings uncover the superficial association between sulfate and adverse health outcomes in epidemiological research and highlight the control of wet smoke plume emissions to mitigate the toxicity effects of acidity.

Smoky Characters in Wine: Distinctive Flavor or Taint?

The frequency of wildfires has significantly increased in recent years, posing concerns for many grapegrowers and winemakers. Exposure of grapes to smoke can result in wines with notable smoky notes, which in severe cases are described as "smoke tainted". However, smoky aromas in wine are not a priori quality defects but may be considered desirable in some styles of wines, as also widely found and appreciated in many spirits. In this perspective, we summarize recent research on sources and assessment of smoky sensory attributes in wine and provide an outlook on opportunities for managing excessive smoky characters.

Exploring the adverse effect of fine particulate matter (PM2.5) on wildland firefighters' pulmonary function and DNA damage.

Chiang Mai encounters severe pollution during the wildfire season. Wildland firefighters encounter various hazards while engaged in fire suppression operations, which encompass significant exposure to elevated concentrations of air pollutants resulting from combustion, especially particulate matter. The adverse effects of wildfire smoke on respiratory health are a significant concern. The objective of this study was to examine the potential adverse effects of PM2.5 exposure on the respiratory function and DNA damage of wildland firefighters. This prospective cohort study conducted in Chiang Mai from January to May 2022 planned to evaluate the health status of wildland firefighters during the pre-peak, peak, and post-peak ambient air pollution seasons. The measurement of PM2.5 was done at every forest fire station, as well as utilizing data from the Pollution Control Department. Participants received general health examinations, spirometry evaluations, and blood tests for DNA damage analysis. Pair t-tests and multiple regression models were used to examine the connection between pulmonary function parameters (FVC, FEV1) and PM2.5 concentration, with a significance level of P < 0.05. Thirty-three peak-season and twenty-one post-peak-season participants were enrolled. Four pre-peak-season wildland firefighters had FVC and FEV1 declines of > 15%. Multiple regression analysis showed a negative association between PM2.5 exposure and FVC% predicted (- 2.81%, 95% CI - 5.27 to - 0.34%, P = 0.027) and a marginally significant negative correlation with FVC (- 114.38 ml, 95% CI - 230.36 to 1.59 ml, P = 0.053). The remaining pulmonary measures showed a statistically insignificant decline. There were no significant changes in DNA damage detected. Wildland firefighters suffered a significant decline in pulmonary function associated with PM2.5 exposure. Spirometry is crucial for monitoring and promptly identifying respiratory issues that occur during wildfire seasons. Further research is recommended to explore DNA damage alterations and their potential association with PM2.5.

Australian Black summer smoke signal on Antarctic aerosol collected between New Zealand and the Ross sea.

Open biomass burning (BB) events are a well-known primary aerosol source, resulting in the emission of significant amount of gaseous and particulate matter and affecting Earth's radiation budget. The 2019-2020 summer, known as "Australian Black Summer", showed exceptional duration and intensity of seasonal wildfires, triggered by high temperatures and severe droughts. Since increasing megafires are predicted due to expected climate changes, it is critical to study the impact of BB aerosol on a large scale and evaluate related transport processes. In this study, five aerosol samples (total suspended particles with a diameter >1 µm) were collected during the XXXV Italian Expedition in Antarctica on board of the R/V Laura Bassi from 6th of January to February 16, 2020, along the sailing route from Lyttelton harbor (New Zealand) to Terra Nova Bay (Antarctica). Levoglucosan and its isomers have been analyzed as markers of BB, together with polycyclic aromatic hydrocarbons (PAHs), sucrose and alcohol sugars. Ionic species and carboxylic acids have been analyzed to support the identification of aerosol sources and its aging. Results showed high levoglucosan concentrations (325-1266 pg m-3) during the campaign, suggesting the widespread presence of smoke in the region, because of huge wildfire releases. Backward trajectories indicated the presence of long-range atmospheric transport from South America, probably carrying wildfires plume, in agreement with literature. Regional sources have been suggested for PAHs, particularly for 3-4 rings' compounds; monosaccharides, sucrose, arabitol, and mannitol were related to marine and biogenic contributions. In a warming climate scenario, more frequent and extensive wildfire episodes are expected in Australia, potentially altering albedo, aerosol radiative properties, and cloud interactions. Therefore, it is crucial to strengthens the investigations on the regional climatic effects of these events in Antarctica.

Evaluating workplace protection factors (WPFs) of different firefighter PPE interface control measures for select volatile organic compounds (VOCs).

Structural firefighters are exposed to a complex set of contaminants and combustion byproducts, including volatile organic compounds (VOCs). Additionally, recent studies have found structural firefighters' skin may be exposed to multiple chemical compounds via permeation or penetration of chemical byproducts through or around personal protective equipment (PPE). This mannequin-based study evaluated the effectiveness of four different PPE conditions with varying contamination control measures (incorporating PPE interface design features and particulate blocking materials) to protect against ingress of several VOCs in a smoke exposure chamber. We also investigated the effectiveness of long-sleeve base layer clothing to provide additional protection against skin contamination. Outside gear air concentrations were measured from within the smoke exposure chamber at the breathing zone, abdomen, and thigh heights. Personal air concentrations were collected from mannequins under PPE at the same general heights and under the base layer at abdomen and thigh heights. Sampled contaminants included benzene, toluene, styrene, and naphthalene. Results suggest that VOCs can readily penetrate the ensembles. Workplace protection factors (WPFs) were near one for benzene and toluene and increased with increasing molecular weight of the contaminants. WPFs were generally lower under hoods and jackets compared to under pants. For all PPE conditions, the pants appeared to provide the greatest overall protection against ingress of VOCs, but this may be due in part to the lower air concentrations toward the floor (and cuffs of pants) relative to the thigh-height outside gear concentrations used in calculating the WPFs. Providing added interface control measures and adding particulate-blocking materials appeared to provide a protective benefit against less-volatile chemicals, like naphthalene and styrene.

Pregnancy exposure to PM2.5 from wildland fire smoke and preterm birth in California.

BACKGROUND: Wildfires in the Western United States are a growing and significant source of air pollution that is eroding decades of progress in air pollution reduction. The effects on preterm birth during critical periods of pregnancy are unknown. METHODS: We assessed associations between prenatal exposure to wildland fire smoke and risk of preterm birth (gestational age < 37 weeks). We assigned smoke exposure to geocoded residence at birth for all live singleton births in California conceived 2007-2018, using weekly average concentrations of particulate matter ≤ 2.5 µm (PM2.5) attributable to wildland fires from United States Environmental Protection Agency's Community Multiscale Air Quality Model. Logistic regression yielded odds ratio (OR) for preterm birth in relation to increases in average exposure across the whole pregnancy, each trimester, and each week of pregnancy. Models adjusted for season, age, education, race/ethnicity, medical insurance, and smoking of the birthing parent. RESULTS: For the 5,155,026 births, higher wildland fire PM2.5 exposure averaged across pregnancy, or any trimester, was associated with higher odds of preterm birth. The OR for an increase of 1 µg/m3 of average wildland fire PM2.5 during pregnancy was 1.013 (95 % CI:1.008,1.017). Wildland fire PM2.5 during most weeks of pregnancy was associated with higher odds. Strongest estimates were observed in weeks in the second and third trimesters. A 10 µg/m3 increase in average wildland fire PM2·5 in gestational week 23 was associated with OR = 1.034; 95 % CI: 1.019, 1.049 for preterm birth. CONCLUSIONS: Preterm birth is sensitive to wildland fire PM2.5; therefore, we must reduce exposure during pregnancy.

California Case Study of Wildfires and Prescribed Burns: PM2.5 Emissions, Concentrations, and Implications for Human Health.

Wildfires are a significant threat to human health, in part through degraded air quality. Prescribed burning can reduce wildfire severity but can also lead to an increase in air pollution. The complexities of fires and atmospheric processes lead to uncertainties when predicting the air quality impacts of fire and make it difficult to fully assess the costs and benefits of an expansion of prescribed fire. By modeling differences in emissions, surface conditions, and meteorology between wildfire and prescribed burns, we present a novel comparison of the air quality impacts of these fire types under specific scenarios. One wildfire and two prescribed burn scenarios were considered, with one prescribed burn scenario optimized for potential smoke exposure. We found that PM2.5 emissions were reduced by 52%, from 0.27 to 0.14 Tg, when fires burned under prescribed burn conditions, considerably reducing PM2.5 concentrations. Excess short-term mortality from PM2.5 exposure was 40 deaths for fires under wildfire conditions and 39 and 15 deaths for fires under the default and optimized prescribed burn scenarios, respectively. Our findings suggest prescribed burns, particularly when planned during conditions that minimize smoke exposure, could be a net benefit for the impacts of wildfires on air quality and health.

Volatile Organic Compound-Based Predictive Modeling of Smoke Taint in Wine.

Smoke taint in wine has become a critical issue in the wine industry due to its significant negative impact on wine quality. Data-driven approaches including univariate analysis and predictive modeling are applied to a data set containing concentrations of 20 VOCs in 48 grape samples and 56 corresponding wine samples with a taster-evaluated smoke taint index. The resulting models for predicting the smoke taint index of wines are highly predictive when using as inputs VOC concentrations after log conversion in both grapes and wines (Pearson Correlation Coefficient PCC = 0.82; R2 = 0.68) and less so when only grape VOCs are used (Pearson Correlation Coefficient PCC = 0.76; R2 = 0.56), and the classification models also show the capacity for detecting smoke-tainted wines using both wine and grape VOC concentrations (Recall = 0.76; Precision = 0.92; F1 = 0.82) or using only grape VOC concentrations (Recall = 0.74; Precision = 0.92; F1 = 0.80). The performance of the predictive model shows the possibility of predicting the smoke taint index of the wine and grape samples before fermentation. The corresponding code of data analysis and predictive modeling of smoke taint in wine is available in the Github repository (https://github.com/IBPA/smoke_taint_prediction).

The research on the effect of temperature of electro-surgical unit to surgical smoke distribution in theatre-in vitro and simulation study.

In electro-surgery, surgical smoke was hazard to surgeons and patient in theatre. In order to institute effective countermeasures, quantifying of the effect of tip temperature of electro-surgical unit to surgical smoke distribution in theatre was studied. The relation of tip temperature to power of electro-surgical unit through in vitro cutting experiment. Based on experiment data, the mathematical model was established to simulate the electro-surgery in laminar operation room. As the power of electro-surgical knife increased, the knife tip temperature increased. Total content of (CO, CO2, CH4, NH3) in waste gas and net flow rate of waste gas at outlet increased with the rising temperature of knife tip and formation rate of condensed tar droplets and non-viable particles also increased. Based on simulation, it was found that The maximum height of surgical smoke rising right above the incision of electro-surgical unit was increased with rising temperature of electro-surgical knife tip. There was a spread route of dispersed surgical smoke near the walls of theatre through natural convection. The polynomial fitting relationship was derived. As the tip temperature of knife increased from 200 to 500°C, maximum ascending height of surgical smoke right above the incision position of electro-surgical unit increased from 1.1 m to 1.45 m. When the tip temperature of electro-knife was more 400°C, the CO content in the surgeon's operating zone was more than 200 ppm, which would cause the surgeon's HbCO level increased. As the patient's tissue in the wound during operation was open, when the electro-knife of more than 400°C, the content of condensed tar droplets and in-viable particle was higher than 20 g/m3 and 12 g/m3 in the zone around patient's wound of open tissue, which should be hazard to health of patient.

Occupational exposure of firefighters to hazardous pollutants during prescribed fires in Portugal.

Firefighters perform high-risk activities and during the course of their functions are highly exposed to a wide range of occupational hazards, including air pollution. Thus, this study aimed to assess the exposure of firefighters in prescribed wildland fires and their occupational exposure, as well as to identify and chemically characterise the particles collected during wildland firefighting and inside fire stations. Exposure to wildfire smoke was evaluated in 7 prescribed fires in Portugal, 2 in the north and 5 in the south of Viseu district. The concentrations of PM2.5, NO2, SO2, CO and VOCs were monitored and exceedances to occupational exposure limit values were identified. Moreover, the chemical composition of PM2.5 was analysed. The results showed that firefighters were exposed to high concentrations of these pollutants during prescribed fires and that, in some cases, exceeded occupational exposure limits, both for time-weighted average concentrations for an 8-h working day (a time-weighted average, TWA) of PM2.5, and for short-term exposure values (STEL) of NO2 and SO2. Despite being exposed to very high concentrations of CO, no exceedances to the occupational exposure values were observed. FT-IR and SEM-EDS allowed to chemically characterise the composition of the particles collected inside the fire stations and also during wildland fires, identifying mainly quartz, aluminium and magnesium silicates, characteristic of earth's crust constituents. and also, fibres that have undergone combustion. Concluding, firefighters' exposure to high concentrations of harmful pollutants, can lead to the degradation of their respiratory health. It is therefore extremely important to increase existing knowledge and conduct further studies, especially longitudinal ones, that can assess their lung function. This will allow an understanding of the impacts of smoke on firefighters' health and develop effective strategies to protect them during wildland firefighting operations.

High-frequency electric knife smoke particles: An experimental study on factors influencing emission characteristics.

During surgery, the use of a high-frequency electric knife produces smoke, which can be harmful to the health of indoor medical staff and patients. The quantity and particle size distribution of smoke particles produced by different tissues may vary. Understanding the release characteristics of these smoke particles is necessary to clarify their impact on the surgical environment and to seek effective smoke control methods. A previous comparative analysis of human and pig tissues revealed that they share similar water and fat compositions in certain anatomical regions. In this study, we investigated the emission characteristics of smoke particles from various tissues of pigs (skeletal muscle, liver, kidney, skin, and subcutaneous fat) under different operating powers of an electric knife. We measured the indoor particle number concentration (particle concentration), and estimated the PM2.5 mass concentration (PM2.5 concentration), particle size distribution, and emission rate of the smoke particles. The study obtained the particle emission rates of different tissues under different electric knife operating powers, results of which showed that (1) during the operation of the electric knife, mainly small particles below 1 µm are produced. Among them, particles of 0.3 µm were the most abundant, with a particle concentration level of up to 109 particles/m3, accounting for 85.17-97.64% of the total particle number, and as the particle size increased, the particle concentration and percentage decreased significantly. (2) The water and fat compositions of different tissues influenced the indoor particle concentration and emission rate of the smoke emitted by the electric knife. Among different tissues, subcutaneous fat tissue had the lowest particle concentration and emission rate. (3) The electric knife operating power mainly affected particles below 1 µm, and except for kidney tissue, the indoor concentration and emission rate of these particle sizes were positively correlated with the power. The experimental results can provide data reference for the use of high-frequency electric knives in surgeries involving different human tissues in the operating room.

Automatic Smoke Analysis in Minimally Invasive Surgery by Image-Based Machine Learning.

INTRODUCTION: Minimally Invasive Surgery uses electrosurgical tools that generate smoke. This smoke reduces the visibility of the surgical site and spreads harmful substances with potential hazards for the surgical staff. Automatic image analysis may provide assistance. However, the existing studies are restricted to simple clear versus smoky image classification. MATERIALS AND METHODS: We propose a novel approach using surgical image analysis with machine learning, including deep neural networks. We address three tasks: 1) smoke quantification, which estimates the visual level of smoke, 2) smoke evacuation confidence, which estimates the level of confidence to evacuate smoke, and 3) smoke evacuation recommendation, which estimates the evacuation decision. We collected three datasets with expert annotations. We trained end-to-end neural networks for the three tasks. We also created indirect predictors using task 1 followed by linear regression to solve task 2 and using task 2 followed by binary classification to solve task 3. RESULTS: We observe a reasonable inter-expert variability for tasks 1 and a large one for tasks 2 and 3. For task 1, the expert error is 17.61 percentage points (pp) and the neural network error is 18.45 pp. For tasks 2, the best results are obtained from the indirect predictor based on task 1. For this task, the expert error is 27.35 pp and the predictor error is 23.60 pp. For task 3, the expert accuracy is 76.78% and the predictor accuracy is 81.30%. CONCLUSIONS: Smoke quantification, evacuation confidence, and evaluation recommendation can be achieved by automatic surgical image analysis with similar or better accuracy as the experts.

Study of waterpipe smoking topography in Fars province of Iran.

Despite a sharp increase in the use of the waterpipe (WP) has been noted recently in Iran, no information is available for the smoking behavior and topography parameters. The present study is intended to obtain the inhalation and smoking topography parameters for the Iranian WP smokers. The smoking data collected from 122 smoking sessions, including 192 WP smokers in the Iranian Fars province have been used to perform smoking topography assessments. The influence of demographic and smoking parameters on puffing data is obtained. Results have indicated that gender and tobacco type strongly affect puff volume and duration. Women smokers inhale smaller volume of smoke than men and puff duration is significantly increased for regular smokers than occasional smokers. However, the results of the present study have not revealed a major effect of age, residence and setting on the puffing behavior.

Intake of tobacco nitrosamines of smokers in various provinces of China and their cancer risk: A meta-analysis.

Nitrosamines are a class of carcinogens which have been detected widely in food, water, some pharmaceuticals as well as tobacco. The objectives of this paper include reviewing the basic information on tobacco consumption and nitrosamine contents, and assessing the health risks of tobacco nitrosamines exposure to Chinese smokers. We searched the publications in English from "Web of Science" and those in Chinese from the "China National Knowledge Infrastructure" in 2022 and collected 151 literatures with valid information. The content of main nitrosamines in tobacco, including 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK), N-nitrosonornicotine (NNN), N-nitrosoanatabine (NAT), N-nitrosoanabasine (NAB), total tobacco-specific nitrosamines (TSNA), and N-nitrosodimethylamine (NDMA) were summarized. The information of daily tobacco consumption of smokers in 30 provinces of China was also collected. Then, the intakes of NNN, NNK, NAT, NAB, TSNAs, and NDMA via tobacco smoke were estimated as 1534 ng/day, 591 ng/day, 685 ng/day, 81 ng/day, 2543 ng/day, and 484 ng/day by adult smokers in 30 provinces, respectively. The cancer risk (CR) values for NNN and NNK inhalation intake were further calculated as 1.44 × 10-5 and 1.95 × 10-4. The CR value for NDMA intake via tobacco smoke (inhalation: 1.66 × 10-4) indicates that NDMA is similarly dangerous in tobacco smoke when compared with the TSNAs. In China, the CR values caused by average nitrosamines intake via various exposures and their order can be estimated as the following: smoke (3.75 × 10-4) > food (1.74 × 10-4) > drinking water (1.38 × 10-5). Smokers in China averagely suffer 200% of extra cancer risk caused by nitrosamines in tobacco when compared with non-smokers.

Molecular-level insights into the temperature-dependent formation dynamics and mechanism of water-soluble dissolved organic carbon derived from biomass pyrolysis smoke.

Water soluble organic carbon (WSOC) derived from biomass pyrolytic smoke is deposited through atmospheric aerosols, negatively affecting aquatic ecological quality and safety. However, the temperature-dependent molecular diversity and dynamic formation of smoke-derived WSOC remain poorly understood in water. Herein, we explored the molecular-level formation mechanism of pyrolytic smoke-derived WSOC in water to explain the evolution, heterogeneous correlations, and sequential responses of molecules and functional groups to increasing pyrolysis temperature. Two-dimensional correlation spectroscopy was used to innovatively establish the characteristic correlations between spectroscopy and Fourier transform-ion cyclotron resonance mass spectrometry. Temperature-dependent formation of WSOC exhibited diversity in absorbance/fluorescent components, unique/common molecules, and their chemical parameters, showing the simultaneous formation and degradation reactions. The common WSOC molecules with lower and higher degrees of oxidation showed significant positive and negative correlations with the fluorescent components, respectively. The primary sequential response of WSOC molecules to increasing pyrolysis temperature (lignin-like molecules â†’ unsaturated hydrocarbons, condensed aromatic molecules â†’ lipid-like/aliphatic-/peptide-like molecules) corresponded to the temperature response of functional groups (carboxylic/alcoholic â†’ polysaccharides â†’ aromatics/amides/phenolic/aliphatic groups), demonstrating well synergistic relationships between them. These novel findings will contribute to the comprehensive understanding and assessments of potential environmental behavior or risks of WSOC in aquatic ecosystems.

Key results from the salt lake regional smoke, ozone, and aerosol study (SAMOZA).

The Northern Wasatch Front area is one of ~ 50 metropolitan regions in the U.S. that do not meet the 2015 O3 standard. To better understand the causes of high O3 days in this region we conducted the Salt Lake regional Smoke, Ozone and Aerosol Study (SAMOZA) in the summer of 2022. The primary goals of SAMOZA were: Measure a suite of VOCs, by Proton Transfer Reaction Mass Spectrometry (PTR-MS) and the 2,4-dinitrophenylhydrazine (DNPH) cartridge method.Evaluate whether the standard UV O3 measurements made in SLC show a positive bias during smoke events, as has been suggested in some recent studies.Use the observations to conduct photochemical modeling and statistical/machine learning analyses to understand photochemistry on both smoke-influenced and non-smoke days.Implications: The Northern Wasatch Front area is one of ~50 metropolitan regions in the U.S. that do not meet the 2015 O3 standard. To better understand the causes of high O3 days in this region we conducted the Salt Lake regional Smoke, Ozone and Aerosol Study (SAMOZA) in the summer of 2022. A number of policy relevant findings are identified in the manuscript including role of smoke and NOx vs VOC sensitivity.

We found no significant difference in the O₃ measurements using a "scrubber-less" UV instrument compared to the standard O₃ measurements at PM_2.5 concentrations up to 60 µg m⁻³.On days with smoke, we found that PM_2.5, CO, O₃ and nearly all VOCs were significantly enhanced. On average, NO_x was also enhanced on days with smoke, but this was complicated by day of week effects.Photochemical modeling of O₃ production rates at the Utah Tech Center demonstrates a strong sensitivity to VOC concentrations and less sensitivity to NOx. For non-smoke days, achieving the current O₃ standard would require regional reductions in VOCs of ~40% or reductions in NO_x ~ 60%.The photochemical modeling shows that formaldehyde and other OVOCs, along with alkenes, were the most important O₃ precursors.Generalized Additive Modeling (GAM) gave similar MDA8 O₃ enhancements on smoky days as the photochemical modeling. Analysis of the GAM results show that 23% of the smoke days have GAM residuals that exceed the U.S. EPA's criteria for inclusion as exceptional event documentation.