Bulk and molecular-level composition of primary organic aerosol from wood, straw, cow dung, and plastic burning

During the past decades, the source apportionment of organic aerosol (OA) in ambient air has been improving substantially. The database of source retrieval model-resolved mass spectral profiles for different sources has been built with the aerosol mass spectrometer (AMS). However, distinguishing similar sources (such as wildfires and residential wood burning) remains challenging, as the hard ionization of the AMS mostly fragments compounds and therefore cannot capture detailed molecular information. Recent mass spectrometer technologies of soft ionization and high mass resolution have allowed for aerosol characterization at the molecular formula level. In this study, we systematically estimated the emission factors and characterized the primary OA (POA) chemical composition with the AMS and the extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) for the first time from a variety of solid fuels, including beech logs, spruce and pine logs, spruce and pine branches and needles, straw, cow dung, and plastic bags. The emission factors of organic matter estimated by the AMS and hydrocarbon gases estimated by the total hydrocarbon analyzer are 16.2 ± 10.8 g kg−1 and 30.3 ± 8.5 g kg−1 for cow dung burning, which is generally higher than that of wood (beech, spruce, and pine), straw, and plastic bag burning (in the range from 1.1 to 6.2 g kg−1 and 14.1 to 19.3 g kg−1). The POA measured by the AMS shows that the f60 (mass fraction of m/z 60) varies from 0.003 to 0.04 based on fuel types and combustion efficiency for wood (beech, spruce, and pine) and cow dung burning. On a molecular level, the dominant compound of POA from wood, straw, and cow dung is C6H10O5 (mainly levoglucosan), contributing ∼ 7 % to ∼ 30 % of the total intensity, followed by C8H12O6 with fractions of ∼ 2 % to ∼ 9 %. However, as they are prevalent in all burning of biomass material, they cannot act as tracers for the specific sources. By using the Mann–Whitney U test among the studied fuels, we find specific potential new markers for these fuels from the measurement of the AMS and EESI-TOF. Markers from spruce and pine burning are likely related to resin acids (e.g., compounds with 20–21 carbon atoms). The product from the pyrolysis of hardwood lignins is found especially in beech log burning. Nitrogen-containing species are selected markers primarily for cow dung open burning. These markers in the future will provide support for the source apportionment.</p

Particle-bound reactive oxygen species (PB-ROS) emissions and formation pathways in residential wood smoke under different combustion and aging conditions

International audienceWood combustion emissions can induce oxida-tive stress in the human respiratory tract by reactive oxygen species (ROS) in the aerosol particles, which are emitted either directly or formed through oxidation in the atmosphere. To improve our understanding of the particle-bound ROS (PB-ROS) generation potential of wood combustion emissions, a suite of smog chamber (SC) and potential aerosol mass (PAM) chamber experiments were conducted under well-determined conditions for different combustion devices and technologies, different fuel types, operation methods, combustion regimes, combustion phases, and aging conditions. The PB-ROS content and the chemical properties of the aerosols were quantified by a novel ROS an-alyzer using the DCFH (2 ,7-dichlorofluorescin) assay and a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). For all eight combustion devices tested, primary PB-ROS concentrations substantially increased upon aging. The level of primary and aged PB-ROS emission factors (EF ROS) were dominated by the combustion device (within different combustion technologies) and to a greater extent by the combustion regimes: the variability within one device was much higher than the variability of EF ROS from different devices. Aged EF ROS under bad combustion conditions were ∼ 2-80 times higher than under optimum combustion conditions. EF ROS from automatically operated combustion devices were on average 1 order of magnitude lower than those from manually operated devices, which indicates that automatic combustion devices operated at optimum conditions to achieve near-complete combustion should be employed to minimize PB-ROS emissions. The use of an elec-trostatic precipitator decreased the primary and aged ROS emissions by a factor of ∼ 1.5 which is however still within the burn-to-burn variability. The parameters controlling the PB-ROS formation in secondary organic aerosol were investigated by employing a regression model, including the fractions of the mass-to-charge ratios m/z 44 and 43 in secondary organic aerosol (SOA; f 44−SOA and f 43−SOA), the OH exposure, and the total organic aerosol mass. The regression model results of the SC and PAM chamber aging experiments indicate that the PB-ROS content in SOA seems to increase with the SOA oxidation state, which initially increases with OH exposure and decreases with the additional partitioning of semi-volatile components with lower PB-ROS content at higher OA concentrations, while further aging seems to result in a decay of PB-ROS. The results and the special data analysis methods deployed in this study could provide a model for PB-ROS analysis of further wood or other combustion studies investigating different combustion conditions and aging methods

Gas-phase composition and secondary organic aerosol formation from standard and particle filter-retrofitted gasoline direct injection vehicles investigated in a batch and flow reactor

Gasoline direct injection (GDI) vehicles have recently been identified as a significant source of carbonaceous aerosol, of both primary and secondary origin. Here we investigated primary emissions and secondary organic aerosol (SOA) from four GDI vehicles, two of which were also retrofitted with a prototype gasoline particulate filter (GPF). We studied two driving test cycles under cold- and hot-engine conditions. Emissions were characterized by proton transfer reaction time-of-flight mass spectrometry (gaseous non-methane organic compounds, NMOCs), aerosol mass spectrometry (sub-micron non-refractory particles) and light attenuation measurements (equivalent black carbon (eBC) determination using Aethalometers) together with supporting instrumentation. Atmospheric processing was simulated using the PSI mobile smog chamber (SC) and the potential aerosol mass oxidation flow reactor (OFR). Overall, primary and secondary particulate matter (PM) and NMOC emissions were dominated by the engine cold start, i.e., before thermal activation of the catalytic after-treatment system. Trends in the SOA oxygen to carbon ratio (O&thinsp;:&thinsp;C) for OFR and SC were related to different OH exposures, but divergences in the H&thinsp;:&thinsp;C remained unexplained. SOA yields agreed within experimental variability between the two systems, with a tendency for higher values in the OFR than in the SC (or, vice versa, lower values in the SC). A few aromatic compounds dominated the NMOC emissions, primarily benzene, toluene, xylene isomers/ethylbenzene and C3-benzene. A significant fraction of the SOA was explained by those compounds, based on comparison of effective SOA yield curves with those of toluene, o-xylene and 1,2,4-trimethylbenzene determined in our OFR, as well as others from literature. Remaining discrepancies, which were smaller in the SC and larger in the OFR, were up to a factor of 2 and may have resulted from diverse reasons including unaccounted precursors and matrix effects. GPF retrofitting significantly reduced primary PM through removal of refractory eBC and partially removed the minor POA fraction. At cold-started conditions it did not affect hydrocarbon emission factors, relative chemical composition of NMOCs or SOA formation, and likewise SOA yields and bulk composition remained unaffected. GPF-induced effects at hot-engine conditions deserve attention in further studies.</p

A sustainability-based socio-technical-environmental project selection algorithm

Including environmental and health impacts in project option selection is important to serve humanity and reduce the adverse effects of development. An algorithm is introduced here that includes lifecycle costs, avoided losses, users’ willingness to pay and value per statistical life (VSL), and both environmental and health impacts. The algorithm is entitled the Socio-Technical-Environmental Project Selection (STEPS) algorithm and incorporates social and health aspects through the willingness to pay, technical aspects through the engineering design, and economic aspects through the lifecycle costs. The algorithm consists of estimating the various quantities needed, such as lifecycle costs, benefits (avoided mortality and infrastructure losses), willingness to pay, and the Environmental Protection Agency’s Maximum Contaminant Level (EPA-MCL). These values are plotted with the environmental and health impacts on the horizontal axis and the Net Cost (equal to the lifecycle cost minus the benefits) on the vertical axis. The most balanced option is the one that plots closest to the origin of the plot. The new algorithm is demonstrated on project selection for the elimination of riverbank erosion using recycled concrete aggregate (RCA) as riprap. RCA uses previously used crushed concrete from demolition as aggregate for any beneficial purpose such as aggregate for new concrete or riprap, as in this case. The disadvantage of RCA, however, is that harmful chemicals leach out when exposed to water. Four options were considered, namely (1) do nothing, (2) use RCA as a riverbank erosion countermeasure, (3) use RCA with a leachate treatment system, and (4) use rock riprap instead of RCA. It was found that the proposed STEPS algorithm leads to the selection of Option 3 with RCA riprap and leachate treatment. Selecting by cost alone would have led to Option 2, which also happens to result in a violation of the EPA-MCL for the arsenic leachate. In addition, Option 4 would have been selected without considering RCA or the problem with landfills reaching capacity with the addition of crushed concrete. The STEPS algorithm, therefore, resulted in the most sustainable solution considering both the lifecycle cost and health and environmental impacts

Risk Factors for Intravesical Recurrence After Minimally Invasive Nephroureterctomy for Upper Tract Urothelial Cancer (Robuust Collaboration)

PURPOSE: Intravesical recurrence (IVR) after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC) has an incidence of approximately 20-50%. Studies to date have been composed of mixed treatment cohorts - open, laparoscopic, and robotic. The objective of this study is to assess clinicopathologic risk factors for intravesical recurrence after RNU for UTUC in a completely minimally invasive cohort. MATERIALS AND METHODS: We performed a multicenter, retrospective analysis of 485 patients with UTUC without prior or concurrent bladder cancer who underwent robotic or laparoscopic RNU. Patients were selected from an international cohort of 17 institutions across the United States, Europe, and Asia. Univariate and multiple Cox regression models were used to identify risk factors for bladder recurrence. RESULTS: A total of 485 (389 robotic, 89 laparoscopic) patients were included in analysis. Overall, 110 (22.7%) of patients developed IVR. The average time to recurrence was 15.2 months (SD 15.5 months). Hypertension was a significant risk factor on multiple regression [HR 1.99, CI 1.06; 3.71, p=0.030]. Diagnostic ureteroscopic biopsy incurred a 50% higher chance of developing IVR [HR 1.49, CI 1.00; 2.20, p=0.048]. Treatment specific risk factors included positive surgical margins [HR 3.36, CI 1.36; 8.33, p=0.009] and transurethral resection for bladder cuff management [HR 2.73, CI 1.10; 6.76, p=0.031]. CONCLUSIONS: IVR after minimally RNU for UTUC is a relatively common event. Risk factors include a ureteroscopic biopsy, transurethral resection of the bladder cuff, and positive surgical margins. When possible, avoidance of transurethral resection of the bladder cuff and alternative strategies for obtaining biopsy tissue sample should be considered

Practice trends for perioperative intravesical chemotherapy in upper tract urothelial carcinoma: Low but increasing utilization during minimally invasive nephroureterectomy.

INTRODUCTION: Perioperative intravesical chemotherapy (IVC) at or around the time of radical nephroureterectomy (RNU) reduces the risk of intravesical recurrence. Guidelines since 2013 have recommended its use. The objective of this study is to examine IVC utilization and determine predictors of its administration within a large international consortium. METHODS AND MATERIALS: Data was collected from 17 academic centers on patients who underwent robotic/laparoscopic RNU between 2006 and 2020. Patients who underwent concomitant radical cystectomy and cases in which IVC administration details were unknown were excluded. Univariate and multivariate analyses were utilized to determine predictors of IVC administration. A Joinpoint regression was performed to evaluate utilization by year. RESULTS: Six hundred and fifty-nine patients were included. A total of 512 (78%) did not receive IVC while 147 (22%) did. Non-IVC patients were older (P \u3c 0.001), had higher ECOG scores (P = 0.003), and had more multifocal disease (23% vs. 12%, P = 0.005). Those in the IVC group were more likely to have higher clinical T stage disease (P = 0.008), undergone laparoscopic RNU (83% vs. 68%, P \u3c 0.001), undergone endoscopic management of the bladder cuff (20% vs. 4%, P = 0.008). Multivariable regression showed that decreased age (OR 0.940, P \u3c 0.001), laparoscopic approach (OR 2.403, P = 0.008), and endoscopic management of the bladder cuff (OR 7.619, P \u3c 0.001) were significant predictors favoring IVC administration. Treatment at a European center was associated with lower IVC use (OR 0.278, P = 0.018). Overall utilization of IVC after the 2013 European Association of Urology (EAU) guideline was 24% vs. 0% prior to 2013 (P \u3c 0.001). Limitations include limited data regarding IVC timing/agent and inclusion of minimally invasive RNU patients only. CONCLUSIONS: While IVC use has increased since being added to the EAU UTUC guidelines, its use remains low at academic centers, particularly within Europe

Risk Factors for Intravesical Recurrence after Minimally Invasive Nephroureterectomy for Upper Tract Urothelial Cancer (ROBUUST Collaboration).

PURPOSE: Intravesical recurrence (IVR) after radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC) has an incidence of approximately 20%-50%. Studies to date have been composed of mixed treatment cohorts-open, laparoscopic and robotic. The objective of this study is to assess clinicopathological risk factors for intravesical recurrence after RNU for UTUC in a completely minimally invasive cohort. MATERIALS AND METHODS: We performed a multicenter, retrospective analysis of 485 patients with UTUC without prior or concurrent bladder cancer who underwent robotic or laparoscopic RNU. Patients were selected from an international cohort of 17 institutions across the United States, Europe and Asia. Univariate and multiple Cox regression models were used to identify risk factors for bladder recurrence. RESULTS: A total of 485 (396 robotic, 89 laparoscopic) patients were included in analysis. Overall, 110 (22.7%) of patients developed IVR. The average time to recurrence was 15.2 months (SD 15.5 months). Hypertension was a significant risk factor on multiple regression (HR 1.99, CI 1.06; 3.71, p=0.030). Diagnostic ureteroscopic biopsy incurred a 50% higher chance of developing IVR (HR 1.49, CI 1.00; 2.20, p=0.048). Treatment specific risk factors included positive surgical margins (HR 3.36, CI 1.36; 8.33, p=0.009) and transurethral resection for bladder cuff management (HR 2.73, CI 1.10; 6.76, p=0.031). CONCLUSIONS: IVR after minimally invasive RNU for UTUC is a relatively common event. Risk factors include a ureteroscopic biopsy, transurethral resection of the bladder cuff, and positive surgical margins. When possible, avoidance of transurethral resection of the bladder cuff and alternative strategies for obtaining biopsy tissue sample should be considered

Single stage Xi® robotic radical nephroureterectomy for upper tract urothelial carcinoma: surgical technique and outcomes

BACKGROUND: Radical nephroureterectomy (RNU) represents the standard of care for high grade upper tract urothelial carcinoma (UTUC). Open and laparoscopic approaches are well-established treatments, but evidence regarding robotic RANU is growing. The introduction of the Xi® system facilitates the implementation of this multi-quadrant procedure. The aim of this video-article is to describe the surgical steps and the outcomes of Xi® robotic RNU. METHODS: Single stage Xi® robotic RNU without patients repositioning and robot re-docking were done between 2015 and 2019 and collected in a large worldwide multi-institutional study, the ROBotic surgery for Upper tract Urothelial cancer STudy (ROBUUST). Institutional review board approval and data share agreement were obtained at each center. Surgical technique is described in detail in the accompanying video. Descriptive statistics of baseline characteristics and surgical, pathological, and oncological outcomes were analyzed. RESULTSː Overall, 148 patients were included in the analysis; 14% had an ECOG \u3e1 and 68.2% ASA ≥3. Median tumor dimension was 3.0 (IQR:2.0-4.2) cm and 34.5% showed hydronephrosis at diagnosis. Forty-eight% were cT1 tumors. Bladder cuff excision and lymph node dissection were performed in 96% and 38.1% of the procedures, respectively. Median operative time and estimated blood loss were 215.5 (IQR:160.5-290.0) minutes and 100.0 (IQR: 50.0-150.0) mL, respectively. Approximately 56% of patients took opioids during hospital stay for a total morphine equivalent dose of 22.9 (IQR:16.0-60.0) milligrams equivalent. Postoperative complications were 26 (17.7%), with 4 major (15.4%). Seven patients underwent adjuvant chemotherapy, with median number of cycles of 4.0 (IQR:3.0-6.0). CONCLUSIONS: Single stage Xi® RNU is a reproducible and safe minimally invasive procedure for treatment of UTUC. Additional potential advantages of the robot might be a wider implementation of LND with a minimally invasive approach