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Gas flaring from oil and gas fields is a significant source of black carbon (BC) emissions, a component of particulate matter that damages health and warms the climate. Observations from the Visible Infrared Imaging Radiometer Suite (VIIRS) satellite instrument indicate that approximately 17.2 billion cubic meters (bcm) of gas was flared from upstream oil and gas operations in the United States in 2019. Based on an emissions factor equation that accounts for the higher heating value of the gas, that corresponded to nearly 16,000 tons of BC emitted, though estimates vary widely across published emissions factors. In this study, we used three reduced-form air quality and health effect models to estimate the health impacts from the flaring-emitted BC particulate matter in the United States. The three models—EASIUR, AP3, and InMAP—predict 26, 48, and 53 premature deaths, respectively, in 2019. The mortality range expands from 5 to 360 deaths annually if alternative emission factors are used. This study shows that reduced-form models can be useful to estimate the impacts of numerous dispersed emissions sources such as flares, and that further research is needed to better quantify BC emissions factors from flares. [ABSTRACT FROM AUTHOR]

At US-Mexico border Ports of Entry, vehicles idle for long times waiting to cross northbound into the US. Long wait times at the border have mainly been studied as an economic issue, however, exposures to emissions from idling vehicles can also present an exposure risk. Here we present the first data on in-vehicle exposures to driver and passengers crossing the US-Mexico border at the San Ysidro, California Port of Entry (SYPOE). Participants were recruited who regularly commuted across the border in either direction and told to drive a scripted route between two border universities, one in the US and one in Mexico. Instruments were placed in participants' cars prior to commute to monitor-1-minute average levels of the traffic pollutants ultrafine particles (UFP), black carbon (BC) and carbon monoxide (CO) in the breathing zone of drivers and passengers. Location was determined by a GPS monitor. Results reported here are for 68 northbound participant trips. The highest median levels of in-vehicle UFP were recorded during the wait to cross at the SYPOE (median 29,692 particles/cm 3 ) significantly higher than the portion of the commute in the US (median 20,508 particles/cm 3 ) though not that portion in Mexico (median 22, 191 particles/cm 3 ). In-vehicle BC levels at the border were significantly lower than in other parts of the commute. Our results indicate that waiting in line at the SYPOE contributes a median 62.5% (range 15.5%–86.0%) of a cross-border commuter's exposure to UFP and a median 44.5% (range (10.6–79.7%) of exposure to BC inside the vehicle while traveling in the northbound direction. Reducing border wait time can significantly reduce in-vehicle exposures to toxic air pollutants such as UFP and BC, and these preventable exposures can be considered an environmental justice issue. [ABSTRACT FROM AUTHOR]

[Display omitted] • Analysis of long-term exposure to PM 2.5 major components and overall mortality among the elderly in the southeastern United States. • A large-scale population-based cohort study by leveraging fine-resolution PM 2.5 components data and the Medicare population. • We observed elevated all-cause mortality associated with long-term exposure to black carbon, organic matters, nitrate, and soil particles. • Better understanding of component-specific effects of PM 2.5 on all-cause mortality could inform pollution control policies on specific sources. Long-term exposure to fine particulate matter (PM 2.5) mass has been associated with adverse health effects. However, the health effects of PM 2.5 components have been less studied. There is a pressing need to better understand the relative contribution of components of PM 2.5 , which can lay the scientific basis for designing effective policies and targeted interventions. We conducted a population-based cohort study, comprising all Medicare enrollees aged 65 or older in the southeastern United States from 2000 to 2016, to explore the associations between long-term exposure to PM 2.5 major components and all-cause mortality among the elderly. Based on well-validated prediction models, we estimated ZIP code-level annual mean concentrations for five major PM 2.5 components, including black carbon (BC), nitrate (NIT), organic matter (OM), sulfate (SO 4), and soil particles. Data were analyzed using Cox proportional hazards models, adjusting for potential confounders. The cohort comprised 13,590,387 Medicare enrollees and a total of 107,191,652 person-years. In single-component models, all five major PM 2.5 components were significantly associated with elevated all-cause mortality. The hazard ratios (HR) per interquartile range (IQR) increase in exposure were 1.027 (95% CI: 1.025–1.030), 1.012 (95% CI: 1.010–1.013), 1.018 (95% CI: 1.017–1.020), 1.021 (95% CI: 1.017–1.024), and 1.004 (95% CI: 1.003–1.006) for BC, NIT, OM, SO 4 , and soil particles, respectively. While the effect estimate of soil component was statistically significant, it is much smaller than those of combustion-related components. Our study provides epidemiological evidence that long-term exposure to major PM 2.5 components is significantly associated with elevated mortality. [ABSTRACT FROM AUTHOR]

Abstract: This study examines the role of horizontal grid resolution on the performance of the regional three dimensional chemical transport model (CTM) PMCAMx. Two cases were investigated. First, the model was applied over the Northeastern United States with grid resolutions of 36 and 12 km during both a summer and a winter period. In this case the emission inventory was simply interpolated from the low resolution version. In the second case a multi-scale 36/4 km grid resolution is used over Western Europe with high resolution (4 × 4 km) emissions. The improvement in model predictions with the fine grid is modest during the summer and more significant during wintertime at both domains. Major differences are predicted mostly for primary (organics and black carbon (BC)) rather than secondary (e.g. sulfate) species. The use of high grid resolution decreases the bias for BC concentration by more than 30% in the Northeastern US during wintertime. In the Megacity of Paris, using high resolution emissions and a 4-km grid decreases the fractional bias for organic aerosol (OA) from 80% to 60% in the city center and produces much larger spatial concentration gradients in the domain as compared to the emissions being interpolated. These results suggest that future work should combine high grid resolution with high resolution emissions, taking into consideration, though, that the grid resolution is not currently the major source of the discrepancies between model predictions and observations. [Copyright &y& Elsevier]

Abstract: The sectoral and regional contributions from northern hemisphere anthropogenic and biomass burning emission sectors to black carbon (BC) distributions over the continental United States (CONUS) in summer 2008 are studied using the Sulfur Transport and dEposition Model (STEM). North American (NA) emissions heavily (>70% of total emissions) affect the BC levels from the surface to ∼5 km, while non-NA plumes compose more than half of the BC above ∼5 km. Among all sectors, NA and non-NA biomass burning, NA transportation and non-NA residential emissions are the major contributors. The sectoral contributions vary among ten regions defined by the US Environmental Protection Agency (EPA): NA anthropogenic emissions enhance northeastern US BC levels; biomass burning strongly impacts northern California and southeastern US; and the influence of extra-regional plumes is largest in the northwestern US but extends to eastern US. The mean contribution from non-NA sources to US surface BC is ∼0.05 μg m−3, with a maximum value of ∼0.11 μg m−3 in the northwestern US. The non-NA contributions to column BC are higher than to surface BC, ranging from 30% to 80%, depending on region. EPA region 8 is most sensitive to extra-regional BC, partially explaining the observed increasing BC trend there during the past decades associated with the increasing Asian BC emissions. Measurements from the June 24 DC-8 flight during the ARCTAS-CARB field campaign show that BC/(organic matter + nitrate + sulfate) mass ratios fairly well represent BC''s warming potential over southern California, which can be approximated by BC/(organic matter + sulfate) and BC/sulfate for plumes affected and unaffected by fires, respectively. The responses of BC/(organic matter + sulfate) and BC/sulfate to removing each emission sector are further discussed, indicating that mitigating NA transportation emissions has the highest potential for regional air quality and climate co-benefits. [Copyright &y& Elsevier]

Abstract: An ambient air monitoring campaign was performed in six counties (Sacramento, CA; Maricopa, AZ; Anoka, MN; Jefferson, KY; Harris, TX; and Pinellas, FL) between January 2008 and September 2009. The purpose of this paper is to compare the spatial and temporal variability of black carbon (BC) and particle-bound polycyclic aromatic hydrocarbons (p-PAHs), across these counties using continuous monitoring instruments – an Aethalometer and a Photoelectric Aerosol Sensor reporting in units of μg m−3 and fA, respectively. We explored temporal trends in these measurements to assess the potential impact of local combustion sources on air quality. Median BC concentrations ranged from 0.13 to 0.53 μg m−3; and median p-PAH values ranged from 0.31 to 4.18 fA. Hourly BC and p-PAH were elevated during morning rush hour and rapidly decreased later in the morning. Nighttime increases in BC and p-PAH were also observed in most counties. Diurnal patterns of BC and p-PAH were different on weekdays compared to weekends. Profiles of hourly ratios of p-PAH/BC in combination with meteorological data can provide insight into potential sources across the sites. Hourly ratios of p-PAH/BC which peaked during early morning and late afternoon hours suggest a dominating contribution of motor vehicle sources in four of the six counties. In two counties, hourly ratios remained elevated for several hours after rush hour and did not show a distinctive peak suggesting additional sources of BC and p-PAH. Such profiles were seen in both Jefferson KY and Harris TX, and may be attributed to coal combustion, petro-chemical industry and shipping activities, respectively. These results suggest that measurements of BC and p-PAH, combined with meteorological information and emission data are potentially useful to identify combustion sources impacting air quality. More research combining BC and p-PAH measurements with detailed source apportionment data is needed to more fully evaluate the utility of these real-time measures. [Copyright &y& Elsevier]

There has been increasing recognition of the important role that aerosols such as black carbon (BC) play in influencing net climate forcing, in particular the high rates of warming in the Arctic, and there is significant interest in reducing BC emissions. In order to assess mitigation options, there is a need for a better understanding of how current air quality policies designed for particulate matter reductions affect BC emissions and for the development of improved BC specific marginal abatement cost (MAC) curves. Using data from the United States (US), we assess the effects of existing air quality regulations on projected BC emissions (diesel fuel regulations in particular are already having significant effects). We also identify key US-specific abatement strategies and present MAC curves for further reducing BC emissions from two key US sources. This analysis may serve to inform similar research on BC mitigation in other regions and sectors. [ABSTRACT FROM AUTHOR]

Abstract: Semi-continuous and 24-h averaged measurements of fine carbonaceous aerosols were made concurrently at three sites within each of two U.S. Midwestern Cities; Detroit, Michigan and Cleveland, Ohio; during two, one-month intensive campaigns conducted in July of 2007 and January & February of 2008. A comparison of 24-h measurements revealed substantial intra-urban variability in carbonaceous aerosols consistent with the influence of local sources, and excesses in both PM2.5 organic carbon (OC) and elemental carbon (EC) were identified at individual sites within each city. High time-resolved black carbon (BC) measurements indicated that elemental carbon concentrations were higher at sites adjacent to freeways and busy surface streets, and temporal patterns suggested that excess EC at sites adjacent to freeways was dominated by mobile source emissions while excesses in EC away from traffic corridors was dominated by point/area source emissions. The site-to-site variability in OC concentrations was approximately 7% within the neighborhood scale (0.5–4 km) and between 4 and 27% at the urban scale (4–100 km). In contrast, measurements of organic source tracers, in conjunction with a Chemical Mass Balance (CMB) source-apportionment model, indicated that the spatial variation in the contribution of both mobile and stationary sources to PM2.5 OC often exceeded the variation in OC mass concentration by a factor of 3 or more. Markers for mobile sources, biomass smoke, natural gas, and coal combustion differed by as much as 60% within the neighborhood scale and by greater than 200% within the urban scale. The observations made during this study suggest that the urban excess of carbonaceous aerosols is much more complex than has been previously reported and that a more rigorous, source-oriented approach should be taken in order to assess the risk associated with exposure to carbonaceous aerosols within the industrialized environments of the Midwestern United States. [Copyright &y& Elsevier]

Abstract: Our objectives are to evaluate inter-continental source-receptor relationships for fine aerosols and to identify the regions whose emissions have dominant influence on receptor continents. We simulate sulfate, black carbon (BC), organic carbon (OC), and mineral dust aerosols using a global coupled chemistry-aerosol model (MOZART-2) driven with NCEP/NCAR reanalysis meteorology for 1997–2003 and emissions approximately representing year 2000. The concentrations of simulated aerosol species in general agree within a factor of 2 with observations, except that the model tends to overestimate sulfate over Europe in summer, underestimate BC and OC over the western and southeastern (SE) U.S. and Europe, and underestimate dust over the SE U.S. By tagging emissions from ten continental regions, we quantify the contribution of each region''s emissions on surface aerosol concentrations (relevant for air quality) and aerosol optical depth (AOD, relevant for visibility and climate) globally. We find that domestic emissions contribute substantially to surface aerosol concentrations (57–95%) over all regions, but are responsible for a smaller fraction of AOD (26–76%). We define “background” aerosols as those aerosols over a region that result from inter-continental transport, DMS oxidation, and emissions from ships or volcanoes. Transport from other continental source regions accounts for a substantial portion of background aerosol concentrations: 36–97% for surface concentrations and 38–89% for AOD. We identify the Region of Primary Influence (RPI) as the source region with the largest contribution to the receptor''s background aerosol concentrations (or AOD). We find that for dust Africa is the RPI for both aerosol concentrations and AOD over all other receptor regions. For non-dust aerosols (particularly for sulfate and BC), the RPIs for aerosol concentrations and AOD are identical for most receptor regions. These findings indicate that the reduction of the emission of non-dust aerosols and their precursors from an RPI will simultaneously improve both air quality and visibility over a receptor region. [Copyright &y& Elsevier]

Abstract: To increase our understanding of the roles of black carbon (BC), a highly sorptive and recalcitrant material, we measured BC concentrations and fluxes in marine particulate organic carbon (POC) out of the water column in the Gulf of Maine (GoM), a representative coastal area downwind of important BC sources of the Northeastern United States. Concentrations ranged from <0.1 to 16 μg/L in the spring and late summer, typically contributing between 1 and 20% of the POC. Water-column export fluxes were near 10 gBC/m2∙yr. These observations suggest that (a) up to 50% of the “molecularly uncharacterized” POC in this region''s seawater is combustion-derived BC, and (b) the “bioavailabilities” of hydrophobic pollutants like polycyclic aromatic hydrocarbons (PAHs) would be influenced substantially by sorption to BC. The observed BC spatial distributions imply that a large part of the BC was carried offshore by wind and that much of it is accumulated in the coastal sediments. On a global scale, these results suggest the GoM and other coastal areas with similar BC loadings accumulate significant amounts of highly recalcitrant organic carbon that remineralizes on geological time scales in the world''s oceans. [Copyright &y& Elsevier]

This article provides an overview of the development, theoretical basis, regulatory status, and application of the U.S. Environmental Protection Agency's (USEPA's) Equilibrium Partitioning Sediment Benchmarks (ESBs) for PAH mixtures. ESBs are compared to other sediment quality guidelines (SQGs) for PAHs. Data that examine the ability of the ESB approach to predict toxic effects to invertebrates are discussed. A USEPA draft methodology for the development of site-specific ESBs that takes into account the limited bioavailability of PAHs at certain sites is discussed. Research is presented that compares the ability of ESBs and site-specific ESBs to predict the toxicity of sediments collected from manufactured gas plants (MGPs). Site-specific ESBs that accounted for adsorption of PAHs onto black carbon were better predictors of the toxicity of sediments from MGP sites than ESBs that did not account for adsorption to black carbon. [ABSTRACT FROM AUTHOR]

The current technologies to treat hypersaline produced water (PW), such as thermal evaporation, are usually energy-intensive and cost-prohibitive. This study developed a low-cost, robust, solar-driven carbon black and airlaid paper-based evaporator (CAPER) for desalination of PW in the Permian Basin, United States. The study aims to better understand the removal of aromatic organic compounds and heavy metals during solar distillation, water output, and heat transfer. Outdoor experiments using CAPER assisted with polystyrene foam in a single slope, single basin solar still achieved an enhanced average evaporation rate of 2.23 L per m2 per day, 165% higher than that of a conventional solar still. Analysis of heat transfer models demonstrated that CAPER solar evaporation achieved an evaporative heat transfer coefficient of ∼28.9 W m−2·K−1, 27.9% higher than without CAPER. The maximum fractional energy of evaporation and convection heat transfer inside the solar still with and without CAPER was ∼81.4% and ∼78.2%, respectively. For the PW with a total dissolved solids concentration of 134 g L−1, solar distillation removed 99.97% salts and over 98% heavy metals. The high removal efficiency of 99.99% was achieved for Ca, Na, Mg, Mn, Ni, Se, Sr, and V. Organic characterization revealed that solar distillation removed over 83% aromatic compounds. Solar desalination using CAPER provides a low-cost and high-performance process to treat PW with high salinity and complex water chemistry for potential fit-for-purpose beneficial uses. Image 1 • A carbon black and airlaid paper-based solar evaporator (CAPER) was developed. • Outdoor distillation of produced water (PW) achieved evaporation of 2.23 L m−2·d−1. • The evaporation rate of PW with CAPER is 165% higher than without CAPER. • Heat transfer coefficient with CAPER is 27.9% higher than without CAPER. • 99.97% salts, 98% metals, >83% aromatic compounds removed from 134 g L−1 TDS PW. [ABSTRACT FROM AUTHOR]

Biomaterial researchers at Ford Motor Co in Dearborn, MI, USA, have engineered a patent-pending formula to use renewable soy oil to improve rubber car parts and make them more environmentally friendly. They also found that soy-based fillers could provide a partial replacement for carbon black reinforcements in rubber. [ABSTRACT FROM AUTHOR]

Abstract: Activity and stability phases as well as geomorphic processes within the Critical Zone are well known. Erosion and deposition of sediments represent activity; soils represent geomorphic stability phases. Data are presented from a 4m deep sediment section that was dated by luminescence techniques. Upslope erosion and resulting sedimentation started in the late Pleistocene around 18ka until 12ka. Conditions at the study site then changed, which led to the formation of a well-developed soil. Radiocarbon dating of the organic matter yielded ages between 8552 and 8995cal.BP. From roughly 6.2 to 5.4ka another activity phase accompanied by according sediment deposition buried the soil and a new soil, a Cambisol, was formed at the surface. The buried soil is a strongly developed Luvisol. The black colors in the upper part of the buried soil are not the result of pedogenic accumulation of normal organic matter within an A-horizon. Nuclear magnetic resonance spectroscopy clearly documents the high amount of aromatic components (charcoal), which is responsible for the dark color. This indicates severe burning events at the site and the smaller charcoal dust (black carbon) was transported to deeper parts of the profile during the process of clay translocation. [Copyright &y& Elsevier]