Field intercomparison of continuous ambient FRM and FEM NO2 instruments in the Athabasca Oil Sands Region, Alberta, Canada and the potential impact on ambient regulatory compliance.

The Canadian Federal Government promulgated new and lower NO2 Ambient Air Quality Standards (CAAQS) that went into effect in 2020 with additional decreases scheduled for 2025. The new hourly and annual NO2 CAAQS are 60 and 17 ppb, respectively, and the 2025 hourly and annual CAAQS are 42 and 12 ppb, respectively. The province of Alberta has also promulgated Ambient Air Quality Objectives (AAAQO) for NO2 currently set to 159 and 24 ppb on an hourly and annual basis, respectively. The Wood Buffalo Environmental Association (WBEA) in northeastern Alberta, Canada monitors NO2 at 21 community and industrial sites throughout the Athabasca Oil Sands Region (AOSR), for regulatory compliance using Thermo-Environmental (TEI) Model 42i Federal Reference Method (FRM) designated NO-NO2-NOx analyzers. The 42i measures NO directly via NO-O3 chemiluminescence, and NOx following the reduction of oxidized nitrogen to NO by a heated internal molybdenum converter. The difference between the NOx and NO channels is reported as NO2. This study presents the results of a three-year (2018-2021) WBEA comparison of four continuous NO2 analyzers: TEI 42i FRM; the API Model T500U cavity attenuated phase shift (CAPS) Federal Equivalent Method (FEM); a total reactive odd nitrogen analyzer (TEI Model 42i-Y); and a TEI 42i equipped with an external photolytic converter. The study showed that NO2 data from all analyzers were highly correlated and in general agreement, with r2 values (vs. the CAPS) ranging from 0.990-0.997 and slopes ranging from 0.933-0.992. Mean NO2 concentrations over the study period ranged from 7.2-7.5 ppb. Differences between the TEI 42i, TEI 42i-Y, and PhoNO, relative to the CAPS were all positive and highly significant (p < 0.0001), based upon nonparametric tests. The potential impact from the selection of different FRM/FEM measurement methods on current and future Canadian 2025 regulatory compliance in the region is evaluated.Implications: The study objective was to compare/evaluate different regulatory NO2 measurement techniques from a regional monitoring authority in a routine network operational context. Relatively small NO2 differences resulted in significant differences with respect to regulatory compliance triggers, particularly hourly standards based on daily extreme value statistics (e.g., 99th percentiles). For example, mean hourly NO2 △ differences ranged from 0.02-0.26 ppb over the study period but resulted in 2-3 ppb differences in the 3-year hourly CAAQS metrics. These differences could affect regulatory CAAQS and LARP compliance (management level) at monitoring sites observed during 2019 annual and 2020 hourly LARP trigger exceedances.

Ambient PM2.5 organic and elemental carbon in New York City: Changing source contributions during a decade of large emission reductions.

Fine particle (PM2.5) exposure is a public health issue affecting millions of people worldwide. In New York State, significant emission reductions occurred during the past decades due to fuel switching, increased renewable energy, and transformations in buildings and transportation. Between 2002 and 2018, anthropogenic emissions of CO, NOx, SO2, VOCs, and primary PM2.5 declined by 58%, 61%, 89%, 47%, and 29%, respectively, in New York and three adjoining states. Ambient PM2.5 mass concentrations decreased but contributions of source types to changes in PM2.5 elemental carbon (EC) and organic carbon (OC) are incompletely understood. Receptor modeling was used to estimate changing source contributions to EC and OC in New York City (NYC) between 2007 and 2019. Source identification was facilitated by incorporating measurements of CO, NO, NO2, O3, SO2, and speciated hydrocarbons (1,3-butadiene, n-butane, isobutane, n-pentane, isopentane, isoprene, benzene, toluene, xylenes, acetaldehyde, and formaldehyde). Hydrocarbon species identified mobile-source emissions, evaporative emissions, biogenics, and photochemical secondary organic aerosol. At three study locations, predicted reductions of TC (OC + EC) summed over all source types were 1.3 ± 0.2 µg m-3, compared with a measured TC reduction of 1.5 ± 0.2 µg m-3. Declining sulfate concentrations and cleaner mobile sources together reduced the predicted average TC by a combined 1 µg m-3. Smaller changes occurred in other source contributions, e.g., 0.15 ± 0.01 µg m-3 reduction likely in response to NYC regulations related to heating fuel oil. Biomass burning PM2.5 increased between 2007 and 2011, then declined between 2015 and 2019. Reductions contrast with a non-significant increase of 0.05 µg m-3 in photochemical TC. Further opportunities to decrease PM2.5 concentrations include wood burning and photochemical-related OC. Continued temporal analysis and source apportionment will be needed to track changes in air quality and source contributions as jurisdictions expand renewable energy and energy efficiency goals.Implications: Large emission reductions that occurred in the eastern U.S. between 2002 and 2019 lowered average fine particle concentrations in New York City by a factor of two. Secondary organic aerosol concentrations declined as sulfate decreased but increased non-significantly with rising ozone. Cleaner mobile-source emissions lowered elemental and organic carbon concentrations. Opportunities for further reductions of PM2.5 concentrations include biomass burning and photochemical secondary aerosol.

Opioid Overdose Risk in Patients Returning to the Emergency Department for Pain.

OBJECTIVE: Using the Risk Index for Overdose or Serious Opioid-induced Respiratory Depression (CIP-RIOSORD) in patients returning to the emergency department (ED) for pain and discharged with an opioid prescription, we assessed overall opioid overdose risk and compared risk in opioid naive patients to those who are non-opioid naive. DESIGN: This was a secondary analysis from a prospective observational study of patients ≥ 18 years old returning to the ED within 30 days. Data were collected from patient interviews and chart reviews. Patients were categorized as Group 1 (not using prescription opioids) or Group 2 (consuming prescription opioids). Statistical analyses were performed using Fisher's exact and Wilcoxon's rank sum tests. Risk class and probability of overdose was determined using Risk Index for Overdose or Serious Opioid-induced Respiratory Depression (CIP-RIOSORD). RESULTS: Of the 389 enrollees who returned to the ED due to pain within 30 days of an initial visit, 67 (17%) were prescribed opioids. The majority of these patients were in Group 1 (60%). Both Group 1 (n = 40) and Group 2 (n = 27) held an average CIP-RIOSORD risk class of 3. Race significantly differed between groups; the majority of Group 1 self-identified as African American (80%) (P = .0267). There were no differences in age, gender, or CIP-RIOSORD risk class between groups. However, Group 2 had nearly double the number of predictive factors (median = 1.93) as Group 1 (median = 1.18) (P = .0267). CONCLUSIONS: A substantial proportion of patients (25%) were high risk for opioid overdose. CIP-RIOSORD may prove beneficial in risk stratification of patients discharged with prescription opioids from the ED.

Reactive oxidized nitrogen speciation and partitioning in urban and rural New York State.

This study examined reactive oxidized nitrogen (NOy) speciation and partitioning at one urban site, Queens College (QC) in New York City, and one rural site, Pinnacle State Park (PSP) in Addison, New York (NY) from September 2016 to August 2018 and June 2016 to September 2018, respectively. Oxides of nitrogen (NOx), nitric acid (HNO3), particle nitrate (pNO3), peroxy nitrates (PNs), alkyl nitrates (ANs), and NOy measurements were made at both sites. Across all seasons at QC, the median NOx, HNO3, pNO3, PNs, ANs, and NOy concentrations were 10.99, 0.49, 0.24, 0.62, 0.94, and 13.95 parts per billion (ppb), respectively. All-season median percent contributions of NOx, HNO3, pNO3, PNs, and ANs to the total NOy at QC were 77, 4, 2, 5, and 7%, respectively. Therefore, the sum of the individual NOy species (NOyi ≈ NOx + HNO3 + pNO3 + PNs + ANs) accounted for 95% of the total NOy at QC, which was well within measurement uncertainties. At PSP, the median NOx, HNO3, pNO3, PNs, ANs, and NOy concentrations were 0.65, 0.16, 0.12, 0.13, 0.18, and 1.56 ppb, respectively, over all seasons. The median percent contributions of NOx, HNO3, pNO3, PNs, and ANs to NOy over all seasons at PSP were 42, 10, 8, 9, and 12%, respectively. NOyi comprised 81% of NOy across all seasons at PSP, and deviations from 100% closure were generally within measurement uncertainties. Since both datasets yielded NOy budget closure results that were either fully or largely explained by the measurement uncertainties, the observed NOyi is likely representative of ambient NOy in urban and rural New York. The results have implications for understanding the fate of NOx emissions and their impact on local and regional air quality in urban and rural New York State.Implications: Continuous speciated and total reactive oxidized nitrogen (NOy) measurements were made in urban and rural New York from 2016 to 2018. Different NOy species have contrasting effects on the chemistry that impacts ozone (O3) and fine particulate matter (PM2.5) formation and concentrations. Since O3 and PM2.5 are regulated pollutants that have proven difficult to control, the results have implications for current and future air quality policy.

Natural and Anthropogenically Influenced Isoprene Oxidation in Southeastern United States and Central Amazon.

Anthropogenic emissions alter secondary organic aerosol (SOA) formation chemistry from naturally emitted isoprene. We use correlations of tracers and tracer ratios to provide new perspectives on sulfate, NOx, and particle acidity influencing isoprene-derived SOA in two isoprene-rich forested environments representing clean to polluted conditions-wet and dry seasons in central Amazonia and Southeastern U.S. summer. We used a semivolatile thermal desorption aerosol gas chromatograph (SV-TAG) and filter samplers to measure SOA tracers indicative of isoprene/HO2 (2-methyltetrols, C5-alkene triols, 2-methyltetrol organosulfates) and isoprene/NOx (2-methylglyceric acid, 2-methylglyceric acid organosulfate) pathways. Summed concentrations of these tracers correlated with particulate sulfate spanning three orders of magnitude, suggesting that 1 µg m-3 reduction in sulfate corresponds with at least ∼0.5 µg m-3 reduction in isoprene-derived SOA. We also find that isoprene/NOx pathway SOA mass primarily comprises organosulfates, ∼97% in the Amazon and ∼55% in Southeastern United States. We infer under natural conditions in high isoprene emission regions that preindustrial aerosol sulfate was almost exclusively isoprene-derived organosulfates, which are traditionally thought of as representative of an anthropogenic influence. We further report the first field observations showing that particle acidity correlates positively with 2-methylglyceric acid partitioning to the gas phase and negatively with the ratio of 2-methyltetrols to C5-alkene triols.

Ambient concentrations and total deposition of inorganic sulfur, inorganic nitrogen and base cations in the Athabasca Oil Sands Region.

Trace gas, particulate matter and deposition data collected in the Athabasca Oil Sands Region (AOSR) from 2000 to 2017 were evaluated as part of a broad scientific programmatic review. Results showed significant spatial patterns and temporal trends across the region. Concentrations of reactive gases were highest near the center of surface oil sands production operations and decreased towards the edges of the monitoring domain by factors of 8, 20, 4 and 3 for SO2, NO2, HNO3 and NH3, respectively. 18 of 30 sites showed statistically significant (p < 0.05) negative trends in SO2 concentrations suggesting an ~40% decrease since 2000. In contrast, only 2 of 30 sites showed statistically significant temporal trends (1 positive, 1 negative) for NO2. NH3 data showed (i) intermittent wildfire impacts, and (ii) high seasonality, with low concentrations during winter and significantly higher values during the summer. PM10 measurements were more limited, but also showed significant spatio-temporal variability. Comparison of PM10 and PM2.5 data showed that >80% of SO42- was in the PM2.5 fraction, while > 60% of Ca2+, Mg2+, Na+ and Cl- were in the PM10-2.5 fraction. Ion balances of both PM10 and PM2.5 contained cation excesses at near-field oil sand sites, but PM2.5 samples at forest health sites >20 km from surface production locations contained anion excesses. Monthly average concentrations of PM10 ions showed peak Ca2+ during March-April to November, but peak SO42-, NH4+ and NO3- from November-March. Deposition estimates showed rapid declines as a function of distance to oil sand operations. Estimated total N and total S deposition to forest health monitoring sites ranged from 2.0 to 5.7 kg ha-1 a-1 and 2.1-14.0 kg ha-1 a-1, respectively. Potential acid input (PAI) ranged from -0.46 to 0.79 keq ha-1 a-1 and was mostly 0.1-0.2 keq ha-1 a-1 throughout the domain, except for two clusters of sites near oil sand operations.

Use of an epiphytic lichen and a novel geostatistical approach to evaluate spatial and temporal changes in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada.

Temporal and spatial atmospheric deposition trends of elements to the boreal forest surrounding bitumen production operations in the Athabasca Oil Sands Region (AOSR), Alberta, Canada were investigated as part of a long-term lichen bioindicator study. The study focused on eight elements (sulfur, nitrogen, aluminum, calcium, iron, nickel, strontium, vanadium) that were previously identified as tracers for the major oil sand production sources. Samples of the in situ epiphytic lichen Hypogymnia physodes were collected in 2002, 2004, 2008, 2011, 2014, and 2017 within a ~150 km radius from the center of surface oil sand production operations in the AOSR. Site-specific time series analysis conducted at eight jack pine upland sites that were repeatedly sampled generally showed significant trends of increasing lichen concentrations for fugitive dust linked elements, particularly at near-field (<25 km from a major oil sands production operation) sample locations. Multiple regional scale geostatistical models were developed and evaluated to characterize broad-scale changes in atmospheric deposition based on changes in H. physodes elemental concentrations between 2008 and 2014. Empirical Bayesian kriging and cokriging lichen element concentrations with oil sands mining, bitumen upgrading, coke materials handling, and limestone quarry/crushing influence variables produced spatial interpolation estimates with the lowest validation errors. Gridded zonal mean lichen element concentrations were calculated for the two comprehensive sampling years (2008, 2014) and evaluated for spatial and temporal change. Lichen sulfur concentrations significantly increased in every grid cell within the domain with the largest increases (44-88%) in the central valley in close proximity to the major surface oil sand production operations, while a minor nitrogen concentration decrease (-20%) in a single grid cell was observed. The areal extent of fugitive dust element deposition generally increased with significantly higher deposition to lichens restricted to the outer grids of the enhanced deposition field, reflecting new and expanding surface mining activity.

Increasing Isoprene Epoxydiol-to-Inorganic Sulfate Aerosol Ratio Results in Extensive Conversion of Inorganic Sulfate to Organosulfur Forms: Implications for Aerosol Physicochemical Properties.

Acid-driven multiphase chemistry of isoprene epoxydiols (IEPOX), key isoprene oxidation products, with inorganic sulfate aerosol yields substantial amounts of secondary organic aerosol (SOA) through the formation of organosulfur compounds. The extent and implications of inorganic-to-organic sulfate conversion, however, are unknown. In this article, we demonstrate that extensive consumption of inorganic sulfate occurs, which increases with the IEPOX-to-inorganic sulfate concentration ratio (IEPOX/Sulfinorg), as determined by laboratory measurements. Characterization of the total sulfur aerosol observed at Look Rock, Tennessee, from 2007 to 2016 shows that organosulfur mass fractions will likely continue to increase with ongoing declines in anthropogenic Sulfinorg, consistent with our laboratory findings. We further demonstrate that organosulfur compounds greatly modify critical aerosol properties, such as acidity, morphology, viscosity, and phase state. These new mechanistic insights demonstrate that changes in SO2 emissions, especially in isoprene-dominated environments, will significantly alter biogenic SOA physicochemical properties. Consequently, IEPOX/Sulfinorg will play an important role in understanding the historical climate and determining future impacts of biogenic SOA on the global climate and air quality.

Source apportionment of an epiphytic lichen biomonitor to elucidate the sources and spatial distribution of polycyclic aromatic hydrocarbons in the Athabasca Oil Sands Region, Alberta, Canada.

The sources and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) atmospheric deposition in the boreal forests surrounding bitumen production operations in the Athabasca Oil Sands Region (AOSR), Alberta, Canada were investigated as part of a 2014 passive in-situ bioindicator source apportionment study. Epiphytic lichen species Hypogymnia physodes samples (n = 127) were collected within a 150 km radius of the main surface oil sand production operations and analyzed for total sulfur, total nitrogen, forty-three elements, twenty-two PAHs, ten groups of C1-C2-alkyl PAHs and dibenzothiophenes (polycyclic aromatic compounds; PACs), five C1- and C2-alkyldibenzothiophenes, and retene. The ΣPAH + PAC in H. physodes ranged from 54 to 2778 ng g-1 with a median concentration of 317 ng g-1. Source apportionment modeling found an eight-factor solution that explained 99% of the measured ΣPAH + PAC lichen concentrations from four anthropogenic oil sands production sources (Petroleum Coke, Haul Road Dust, Stack Emissions, Raw Oil Sand), two local/regional sources (Biomass Combustion, Mobile Source), and two lichen biogeochemical factors. Petroleum Coke and Raw Oil Sand dust were identified as the major contributing sources of ΣPAH + PAC in the AOSR. These two sources accounted for 63% (43.2 µg g-1) of ΣPAH + PAC deposition to the entire study domain. Of this overall 43.2 µg g-1 contribution, approximately 90% (39.9 µg g-1) ΣPAH + PAC was deposited within 25 km of the closest oil sand production facility. Regional sources (Biomass Combustion and Mobile Sources) accounted for 19% of ΣPAH + PAC deposition to the entire study domain, of which 46% was deposited near-field to oil sand production operations. Source identification was improved over a prior lichen-based study in the AOSR through incorporation of PAH and PAC analytes in addition to inorganic analytes.

Using Pb isotope ratios of particulate matter and epiphytic lichens from the Athabasca Oil Sands Region in Alberta, Canada to quantify local, regional, and global Pb source contributions.

Ambient air particulate matter (PM) was collected at the Wood Buffalo Environmental Association Bertha Ganter Fort McKay monitoring station in the Athabasca Oil Sand Region (AOSR) in Alberta, Canada from February 2010 to July 2011 as part of an air quality source assessment study. Daily 24-hour duration fine (PM2.5) and coarse (PM10-2.5) PM was collected using a sequential dichotomous sampler. 100 pairs of PM2.5 and PM10-2.5 were selected for lead (Pb) concentration and isotope analysis. Pb isotope and concentration results from 250 epiphytic lichen samples collected as far as 160 km from surface mining operations in 2008, 2011, and 2014 were analyzed to examine longer term spatial variations in Pb source contributions. A key finding was recognition of thorogenic 208Pb from eastern Asia in the springtime in the PM2.5 in 2010 and 2011. 206Pb/207Pb and 208Pb/207Pb isotope ratios were used in a three-component mixing model to quantify local, regional, and global Pb sources in the PM and lichen data sets. 47 ±â€¯3% of the Pb in the PM2.5 at AMS-1 was attributed to sources from eastern Asia. Combined results from PM10-2.5 and PM2.5 indicate PM2.5 Pb contributions from eastern Asia (34%) exceed local AOSR sources of PM2.5 Pb (20%), western Canada sources of PM2.5 Pb (19%), and PM10-2.5 Pb from fugitive dust including oil sands (14%), tailings (10%), and haul roads (3%). The lichen analysis indicates regional sources contribute 46% of the Pb, local sources 32%, and global sources 22% over the 2008-2014 timeframe. Local sources dominate atmospheric Pb deposition to lichens at near field sites (0-30 km from mining operations) whereas regional Pb sources are prevalent at distal sites (30-160 km). The Pb isotope methodology successfully quantified trans-Pacific transport of Pb to the AOSR superimposed over the aerosol footprint of the world's largest concentration of bitumen mining and upgrading facilities.

Source apportionment of ambient fine and coarse particulate matter polycyclic aromatic hydrocarbons at the Bertha Ganter-Fort McKay community site in the Oil Sands Region of Alberta, Canada.

A comprehensive filter-based particulate matter polycyclic aromatic hydrocarbon (PAH) source apportionment study was conducted at the Wood Buffalo Environmental Association Bertha Ganter-Fort McKay (BGFM) community monitoring station from 2014 to 2015 to quantify ambient concentrations and identify major sources. The BGFM station is located in close proximity to several surface oil sands production facilities and was previously found to be impacted by their air emissions. 24-hour integrated PM2.5 and PM10-2.5 samples were collected on a 1-in-3-day schedule yielding 108 complete organic/inorganic filter sets for source apportionment modeling. During the study period PM2.5 averaged 8.6 ±â€¯11.8 µg m-3 (mean ±â€¯standard deviation), and PM10-2.5 averaged 8.5 ±â€¯9.5 µg m-3. Wind regression analysis indicated that the oil sands production facilities were significant sources of PM2.5 mass and black carbon (BC), and that wildland fires were a significant source of the highest PM2.5 (>10 µg m-3) and BC events. A six-factor positive matrix factorization (PMF) model solution explained 95% of the measured PM2.5 and 78% of the measured ΣPAH. Five sources significantly contributed to PM2.5 including: Biomass Combustion (3.57 µg m-3; 40%); Fugitive Dust (1.86 µg m-3; 28%); Upgrader Stack Emissions (1.44 µg m-3; 21%); Petrogenic PAH (1.20 µg m-3; 18%); and Transported Aerosol (0.43 µg m-3 and 6%). However, the analysis indicated that only the pyrogenic PAH source factor significantly contributed (78%) to the measured ΣPAH. A five-factor PMF model dominated by fugitive dust sources explained 98% of PM10-2.5 mass and 86% of the ΣPAH. The predominant sources of PM10-2.5 mass were (i) Haul Road Dust (4.82 µg m-3; 53%), (ii) Mixed Fugitive Dust (2.89 µg m-3; 32%), (iii) Fugitive Oil Sand (0.88 µg m-3; 10%), Mobile Sources (0.23 µg m-3; 2%), and Organic Aerosol (0.06 µg m-3; 1%). Only the Organic Aerosol source significantly contributed (86%) to the measured ΣPAH.

Monoterpenes are the largest source of summertime organic aerosol in the southeastern United States.

The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic-biogenic interaction affecting ambient aerosol in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.

Estimating Acute Cardiovascular Effects of Ambient PM2.5 Metals.

BACKGROUND: Few epidemiologic studies have investigated health effects of water-soluble fractions of PM2.5 metals, the more biologically accessible fractions of metals, in their attempt to identify health-relevant components of ambient PM2.5. OBJECTIVES: In this study, we estimated acute cardiovascular effects of PM2.5 components in an urban population, including a suite of water-soluble metals that are not routinely measured at the ambient level. METHODS: Ambient concentrations of criteria gases, PM2.5, and PM2.5 components were measured at a central monitor in Atlanta, Georgia, during 1998-2013, with some PM2.5 components only measured during 2008-2013. In a time-series framework using Poisson regression, we estimated associations between these pollutants and daily counts of emergency department (ED) visits for cardiovascular diseases in the five-county Atlanta area. RESULTS: Among the PM2.5 components we examined during 1998-2013, water-soluble iron had the strongest estimated effect on cardiovascular outcomes [RÍ¡R=1.012 (95% CI: 1.005, 1.019), per interquartile range increase (20.46ng/m3)]. The associations for PM2.5 and other PM2.5 components were consistent with the null when controlling for water-soluble iron. Among PM2.5 components that were only measured during 2008-2013, water-soluble vanadium was associated with cardiovascular ED visits [RÍ¡R=1.012 (95% CI: 1.000, 1.025), per interquartile range increase (0.19ng/m3)]. CONCLUSIONS: Our study suggests cardiovascular effects of certain water-soluble metals, particularly water-soluble iron. The observed associations with water-soluble iron may also point to certain aspects of traffic pollution, when processed by acidifying sulfate, as a mixture harmful for cardiovascular health. https://doi.org/10.1289/EHP2182.

Characterization of organic nitrogen in aerosols at a forest site in the southern Appalachian Mountains.

This study investigates the composition of organic particulate matter in PM2.5 in a remote montane forest in the southeastern US, focusing on the role of organic nitrogen (N) in sulfur-containing secondary organic aerosol (nitrooxy-organosulfates) and aerosols associated with biomass burning (nitro-aromatics). Bulk water-soluble organic N (WSON) represented ~ 14% w/w of water-soluble total N (WSTN) in PM2.5 on average across seasonal measurement campaigns conducted in the spring, summer, and fall of 2015. The largest contributions of WSON to WSTN were observed in spring (~ 18% w/w) and the lowest in the fall (~ 10% w/w). On average, identified nitro-aromatic and nitrooxy-organosulfate compounds accounted for a small fraction of WSON, ranging from ~ 1% in spring to ~ 4% in fall, though were observed to contribute as much as 28% w/w of WSON in individual samples that were impacted by local biomass burning. The highest concentrations of oxidized organic N species occurred during summer (average of 0.65 ng N m-3) along with a greater relative abundance of higher-generation oxygenated terpenoic acids, indicating an association with more aged aerosol. The highest concentrations of nitro-aromatics (e.g., nitrocatechol and methyl-nitrocatechol), levoglucosan, and aged SOA tracers were observed during fall, associated with aged biomass burning plumes. Nighttime nitrate radical chemistry is the most likely formation pathway for nitrooxy-organosulfates observed at this low NO x site (generally < 1 ppb). Isoprene-derived organosulfate (MW216, 2-methyltetrol derived), which is formed from isoprene epoxydiols (IEPOX) under low NO x conditions, was the most abundant individual organosulfate. Concentration-weighted average WSON / WSOC ratios for nitro-aromatics + organosulfates + terpenoic acids were 1 order of magnitude lower than the overall aerosol WSON / WSOC ratio, indicating the presence of other uncharacterized higher-N-content species. Although nitrooxy-organosulfates and nitro-aromatics contributed a small fraction of WSON, our results provide new insight into the atmospheric formation processes and sources of these largely uncharacterized components of atmospheric organic N, which also helps to advance the atmospheric models to better understand the chemistry and deposition of reactive N.

The impact of the 2016 Fort McMurray Horse River Wildfire on ambient air pollution levels in the Athabasca Oil Sands Region, Alberta, Canada.

An unprecedented wildfire impacted the northern Alberta city of Fort McMurray in May 2016 causing a mandatory city wide evacuation and the loss of 2,400 homes and commercial structures. A two-hectare wildfire was discovered on May 1, grew to ~157,000ha by May 5, and continued to burn an estimated ~590,000ha by June 13. A comprehensive air monitoring network operated by the Wood Buffalo Environmental Association (WBEA) in and around Fort McMurray provided essential health-related real-time air quality data to firefighters during the emergency, and provided a rare opportunity to elucidate the impact of gaseous and particulate matter emissions on near-field communities and regional air pollution concentrations. The WBEA network recorded 188 fire-related exceedances of 1-hr and 24-hr Alberta Ambient Air Quality Objectives. Two air monitoring sites within Fort McMurray recorded mean/maximum 1-hr PM2.5 concentrations of 291/5229µgm-3 (AMS-6) and 293/3259µgm-3 (AMS-7) during fire impact periods. High correlations (r2=0.83-0.97) between biomass combustion related gases (carbon monoxide (CO), non-methane hydrocarbons (NMHC), total hydrocarbons (THC), total reduced sulfur (TRS), ammonia) and PM2.5 were observed at the sites. Filter-based 24-hr integrated PM2.5 samples collected every 6 days showed maximum concentrations of 267µgm-3 (AMS-6) and 394µgm-3 (AMS-7). Normalized excess emission ratios relative to CO were 149.87±3.37µgm-3ppm-1 (PM2.5), 0.274±0.002ppmppm-1 (THC), 0.169±0.001ppmppm-1 (NMHC), 0.104±0.001ppmppm-1 (CH4), 0.694±0.007ppbppm-1 (TRS), 0.519±0.040ppbppm-1 (SO2), 0.412±0.045ppbppm-1 (NO), 1.968±0.053ppbppm-1 (NO2), and 2.337±0.077ppbppm-1 (NOX). A subset of PM2.5 filter samples was analyzed for trace elements, major ions, organic carbon, elemental carbon, and carbohydrates. Sample mass reconstruction and fire specific emission profiles are presented and discussed. Potential fire-related photometric ozone instrument positive interferences were observed and were positively correlated with NO and NMHC.

Safety Analysis of Autologous Stem Cell Therapy in a Variety of Degenerative Diseases and Injuries Using the Stromal Vascular Fraction.

BACKGROUND: Stem cells from adipose tissue offer a novel therapy for patients with damaged tissue. Stromal vascular fraction (SVF) injected into patients may reduce inflammation, promote healing, and repair damaged/scarred tissue. SVF can be isolated from fat (adipose) tissue in an outpatient procedure. The SVF population includes mesenchymal stem cells (MSCs), pericytes, endothelial/progenitor cells, fibroblasts and growth factors where the adipocyte (fat cell) population has been removed. Here we describe the use of SVF in the clinic for degenerative diseases in orthopedics, neurological conditions and systemic conditions in 676 patients. METHODS: This study demonstrated the strong safety profile from a multi-center analysis of SVF injection in treating various diseases. Approximately 60 mL of fat tissue was removed from the abdomen or flanks using a local tumescent liposuction procedure. The fat was separated via centrifuge to isolate the SVF and the cells were delivered intraarticularly, intravenously, intrathecally, or intradiscally directly into the same patient. All subjects were monitored for adverse events. RESULTS: The procedure demonstrates exceptional patient safety, and the study underscores the safety of autologous stem cell therapy in general. Few adverse events were reported and were overwhelmingly of mild and transient nature, such as the expected soreness at the site of liposuction and occasional headache. CONCLUSION: The three deaths reported were most likely not related to the treatment but instead to the underlying disease. Our study demonstrates a strong safety profile with low complication rates.

Differential accumulation of PAHs, elements, and Pb isotopes by five lichen species from the Athabasca Oil Sands Region in Alberta, Canada.

A 2014 case study investigated the relative accumulation efficiency of polycyclic aromatic hydrocarbons (PAHs), total sulfur (S), total nitrogen (N), major and minor elements and Pb isotopes in five common lichen species at three boreal forest sites in the Athabasca Oil Sands Region (AOSR) in northeastern Alberta, Canada to identify the optimum lichen species for future biomonitoring. Differences in concentrations of PAHs, multiple elements, and Pb isotopes in fruticose (Bryoria furcellata, Cladina mitis, Evernia mesomorpha) and foliose (Hypogymnia physodes and Tuckermannopsis americana) lichens were found along a 100 km distance gradient from the primary oil sands operations. Integration of insights from emission source samples and oil sands mineralogy in consort with aerosol collection indicates incorporation of more fine particulate matter (PM) into foliose than fruticose lichen biomass. Contrasting PAH with element concentrations allowed lichen species specific accumulation patterns to be identified. The ability of lichen species to incorporate different amounts of gas phase (S and N), petrogenic (V, Ni, Mo), clay (low Si/Al and more rare earth elements), and sand (higher Si/Al and Ti) components from the oil sand operations reflects aerosol particle size and lichen physiology differences that translate into differences in PM transport distances and lichen accumulation efficiencies. Based on these findings Hypogymnia physodes is recommended for future PAH biomonitoring and source attribution studies.

Molecular-Size-Separated Brown Carbon Absorption for Biomass-Burning Aerosol at Multiple Field Sites.

Biomass burning is a known source of brown carbon aerosol in the atmosphere. We collected filter samples of biomass-burning emissions at three locations in Canada and the United States with transport times of 10 h to >3 days. We analyzed the samples with size-exclusion chromatography coupled to molecular absorbance spectroscopy to determine absorbance as a function of molecular size. The majority of absorption was due to molecules >500 Da, and these contributed an increasing fraction of absorption as the biomass-burning aerosol aged. This suggests that the smallest molecular weight fraction is more susceptible to processes that lead to reduced light absorption, while larger-molecular-weight species may represent recalcitrant brown carbon. We calculate that these large-molecular-weight species are composed of more than 20 carbons with as few as two oxygens and would be classified as extremely low volatility organic compounds (ELVOCs).

Source apportionment of ambient fine and coarse particulate matter at the Fort McKay community site, in the Athabasca Oil Sands Region, Alberta, Canada.

An ambient air particulate matter sampling study was conducted at the Wood Buffalo Environmental Association (WBEA) AMS-1 Fort McKay monitoring station in the Athabasca Oil Sand Region (AOSR) in Alberta, Canada from February 2010 to July 2011. Daily 24h integrated fine (PM2.5) and coarse (PM10-2.5) particulate matter was collected using a sequential dichotomous sampler. Over the duration of the study, 392 valid daily dichotomous PM2.5 and PM10-2.5 sample pairs were collected with concentrations of 6.8±12.9µgm-3 (mean±standard deviation) and 6.9±5.9µgm-3, respectively. A subset of 100 filter pairs was selected for element analysis by energy dispersive X-ray fluorescence and dynamic reaction cell inductively coupled plasma mass spectrometry. Application of the U.S. EPA positive matrix factorization (PMF) receptor model to the study data matrix resolved five PM2.5 sources explaining 96% of the mass including oil sands upgrading (32%), fugitive dust (26%), biomass combustion (25%), long-range Asian transport lead source (9%), and winter road salt (4%). An analysis of historical PM2.5 data at this site shows that the impact of smoke from wildland fires was particularly high during the summer of 2011. PMF resolved six PM10-2.5 sources explaining 99% of the mass including fugitive haul road dust (40%), fugitive oil sand (27%), a mixed source fugitive dust (16%), biomass combustion (12%), mobile source (3%), and a local copper factor (1%). Results support the conclusion of a previous epiphytic lichen biomonitor study that near-field atmospheric deposition in the AOSR is dominated by coarse fraction fugitive dust from bitumen mining and upgrading operations, and suggest that fugitive dust abatement strategies targeting the three major sources of PM10-2.5 (e.g., oil sand mining, haul roads, bulk material stockpiles) would significantly reduce near-field atmospheric deposition gradients in the AOSR and reduce ambient PM concentrations in the Fort McKay community.

Assessing the impact of anthropogenic pollution on isoprene-derived secondary organic aerosol formation in PM2.5 collected from the Birmingham, Alabama, ground site during the 2013 Southern Oxidant and Aerosol Study.

In the southeastern US, substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes to fine particulate matter (PM2.5). Laboratory studies have revealed that anthropogenic pollutants, such as sulfur dioxide (SO2), oxides of nitrogen (NO x ), and aerosol acidity, can enhance SOA formation from the hydroxyl radical (OH)-initiated oxidation of isoprene; however, the mechanisms by which specific pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected at the Birmingham, Alabama (BHM), ground site during the 2013 Southern Oxidant and Aerosol Study (SOAS). Sample extracts were analyzed by gas chromatography-electron ionization-mass spectrometry (GC/EI-MS) with prior trimethylsilylation and ultra performance liquid chromatography coupled to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-QTOFMS) to identify known isoprene SOA tracers. Tracers quantified using both surrogate and authentic standards were compared with collocated gas- and particle-phase data as well as meteorological data provided by the Southeastern Aerosol Research and Characterization (SEARCH) network to assess the impact of anthropogenic pollution on isoprene-derived SOA formation. Results of this study reveal that isoprene-derived SOA tracers contribute a substantial mass fraction of organic matter (OM) (~ 7 to ~ 20 %). Isoprene-derived SOA tracers correlated with sulfate ( SO42- ) (r2 = 0.34, n = 117) but not with NO x . Moderate correlations between methacrylic acid epoxide and hydroxymethyl-methyl-α-lactone (together abbreviated MAE/HMML)-derived SOA tracers with nitrate radical production (P[NO3]) (r2 = 0.57, n = 40) were observed during nighttime, suggesting a potential role of the NO3 radical in forming this SOA type. However, the nighttime correlation of these tracers with nitrogen dioxide (NO2) (r2 = 0.26, n = 40) was weaker. Ozone (O3) correlated strongly with MAE/HMML-derived tracers (r2 = 0.72, n = 30) and moderately with 2-methyltetrols (r2 = 0.34, n = 15) during daytime only, suggesting that a fraction of SOA formation could occur from isoprene ozonolysis in urban areas. No correlation was observed between aerosol pH and isoprene-derived SOA. Lack of correlation between aerosol acidity and isoprene-derived SOA is consistent with the observation that acidity is not a limiting factor for isoprene SOA formation at the BHM site as aerosols were acidic enough to promote multiphase chemistry of isoprene-derived epoxides throughout the duration of the study. All in all, these results confirm previous studies suggesting that anthropogenic pollutants enhance isoprene-derived SOA formation.