Overview of Real-World Emission Characterization Methods

Potential toxic components in size-resolved particles and gas from residential combustion: Emission factor and health risk

Particulate matter (PM) from residential combustion is an existential threat to human health. Emission factors (EFs) of multiple potential toxic components (PTCs) in size-resolved PM and gas from eight residential fuel combustion were measured, and size distribution, gas/particle partitioning and health risks of the PTCs were investigated. Average EFs from clean coal and anthracite coal were PTEs (sum of EFs of 11 Potential Toxic Elements, 6.62 mg/kg fuels) > PAHs (sum of 22 Polycyclic Aromatic Hydrocarbons, 1.12 mg/kg) > OPAHs (sum of 5 Oxygenated Polycyclic Aromatic Hydrocarbons, 0.45 mg/kg) > PAEs (sum of 6 Phthalate Esters, 0.11 mg/kg) > NPAHs (sum of 14 Nitropolycyclic Aromatic Hydrocarbons, 16.84 μg/kg) > OPEs (sum of 7 Organophosphate Esters, 7.57 μg/kg) > PCBs (sum of 6 Polychorinated Biphenyls, 0.07 μg/kg), which were 2-3 and 1-2 orders of magnitude lower than the EFs of PTCs (except PTEs) from bituminous coal and biomass. Most PAHs, OPAHs and NPAHs, which may mainly originate from chemical reactions, showed similar size distributions and averagely 85 % concentrated in PM1. PTEs, PAEs, OPEs and PCBs generated from the release from raw fuels may have a higher proportion, so their size distributions were more complex and varied with combustion temperature, volatility of compounds, binding mode of the raw fuels, and so on. In addition, clean coal and high-quality anthracite coal could reduce the health risks from the potential organic toxic components, but also reveal the stumbling block of PTEs in risk control.

A re-analysis and review of elemental and polycyclic aromatic compound deposition in snow and lake sediments from Canada's Oil Sands Region integrating industrial performance and climatic variables

Much of the research from Canada's oil sands region (OSR) shows contaminants of concern (CoCs) throughout the ambient environment surrounding the industrial facilities. While there are some well-established sources of the CoCs, there is also spatial and temporal variability suggesting activity intensity, changes in technology, types and amounts of fuels combusted at the facilities, and climate may affect the results of deposition studies. This study re-analysed published data on the deposition of elements and polycyclic aromatic compounds (PACs) in snow and the sediments of some lakes by incorporating production data from facilities and climate. Using the Elastic Net (EN) regularized regression, variables describing potential associations between facility-specific activity and climate on the deposition of CoCs were identified. Among the selected variables, the combustion of delayed petroleum coke at the Suncor Basemine was associated with the deposition of CoCs, including elements in snow and in some lakes. Similarly, combustion of petroleum coke at Syncrude Mildred Lake was also identified in some models. In both cases, the effects of petroluem coke combustion are likely associated with the emission and deposition of fly ash. The mass of stored petroleum coke was not selected in snow CoC models, but the speed of the wind was a common driver for PACs. However, the mass of stockpiled petcoke was more closely associated with both elements and PACs in lake sediments. While the potential influence of other variables on the occurrence of CoCs in the OSR was also identified, including the production of crude bitumen and synthetic crude, the use of process and natural gases, temperature, and precipitation, these analyses support much of the earlier work and provides additional nuance. While more work is required, these results suggest facility-specific production and climatic data can be coupled with existing approaches to improve the identification of sources of CoCs in Canada's OSR and practices associated with their release.

A decadal synthesis of atmospheric emissions, ambient air quality, and deposition in the oil sands region

This review is part of a series synthesizing peer-reviewed literature from the past decade on environmental monitoring in the oil sands region (OSR) of northeastern Alberta. It focuses on atmospheric emissions, air quality, and deposition in and downwind of the OSR. Most published monitoring and research activities were concentrated in the surface-mineable region in the Athabasca OSR. Substantial progress has been made in understanding oil sands (OS)-related emission sources using multiple approaches: airborne measurements, satellite measurements, source emission testing, deterministic modeling, and source apportionment modeling. These approaches generally yield consistent results, indicating OS-related sources are regional contributors to nearly all air pollutants. Most pollutants exhibit enhanced air concentrations within ~20 km of surface-mining activities, with some enhanced >100 km downwind. Some pollutants (e.g., sulfur dioxide, nitrogen oxides) undergo transformations as they are transported through the atmosphere. Deposition rates of OS-related substances primarily emitted as fugitive dust are enhanced within ~30 km of surface-mining activities, whereas gaseous and fine particulate emissions have a more diffuse deposition enhancement pattern extending hundreds of kilometers downwind. In general, air quality guidelines are not exceeded, although these single-pollutant thresholds are not comprehensive indicators of air quality. Odor events have occurred in communities near OS industrial activities, although it can be difficult to attribute events to specific pollutants or sources. Nitrogen, sulfur, polycyclic aromatic compounds (PACs), and base cations from OS sources occur in the environment, but explicit and deleterious responses of organisms to these pollutants are not as apparent across all study environments; details of biological monitoring are discussed further in other papers in this special series. However, modeling of critical load exceedances suggests that, at continued emission levels, ecological change may occur in future. Knowledge gaps and recommendations for future work to address these gaps are also presented. Integr Environ Assess Manag 2022;18:333-360. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Parent, alkylated, oxygenated and nitro polycyclic aromatic hydrocarbons from raw coal chunks and clean coal combustion: Emission factors, source profiles, and health risks

Residential coals are still inevitable using in developing areas in China. Clean coal briquettes, normally using alkaline substance such as lime or red mud (RM) as the additive, were helpful in pollution emission reduction even without changes of stoves. Studies of atmospheric polycyclic aromatic hydrocarbons (PAHs) emission characteristics from RM clear coal combustion were limited. In this study, emission factors (EFs), sources profiles, and health risks of polycyclic aromatic hydrocarbons (PAHs) in PM_2.5 were investigated for raw coal chunks and clean coal (with red mud) through combustion experiments. EFs of total PAHs were found to be 160.1 ± 100.9 mg·kg^-1 and 19.4 ± 6.1 mg·kg^-1 for bituminous and anthracite raw coal chunks (B-C and A-C), respectively. EFs values were highest for parent PAHs (p-PAHs), followed by oxygenated PAHs (o-PAHs), alkylated PAHs (a-PAHs), and nitro PAHs (n-PAHs). EFs of p-PAHs account for 80% and 52% of total PAHs emissions for B-C and A-C, respectively, while those for o-PAHs are 22.9% and 44.9%, demonstrating residential coal combustion as a significant primary source for p-PAHs and o-PAHs. Clean coals were developed through cold-press technology with red mud (RM) as additive, and clean coals with RM contents of 10% are referred to as B-10% (bituminous) and A-10% (anthracite). Compared to raw coals chunks, EFs were reduced from 128.1, 2.5, 29.3 mg·kg^-1 and 161.8 μg·kg^-1 to 83.5, 1.3, 16.4 mg·kg^-1 and 102.2 μg·kg^-1 by B-10%, and from 10.1, 0.6, 8.7 mg·kg^-1 and 20.6 μg·kg^-1 to 11.9, 0.2, 2.4 mg·kg^-1 and 15.3 μg·kg^-1 by A-10% for p-PAHs, o-PAHs, a-PAHs and n-PAHs, respectively. Diagnostic ratios of 5-Nitroacenaphthene / Acenaphthene (0.02-0.05 for coal, 0.0002 for biomass) can be used to separate residential coal and biomass burning in source analysis. When B-C was replaced by B-10%, both noncancer (0.58 to 0.33 for male, 1.65 to 0.95 for female in hazard quotient) and cancer risks (5.68 × 10^-4 to 2.73 × 10^-4 for male, 2.63 × 10^-3 to 1.27 × 10^-3 for female) can be reduced. o-PAHs should be paid more attention because of its high cancer risks caused by 6H-Benzo(C,D)Pyrene-6-One (1.74 × 10^-5 for male, 8.07 × 10^-5 for female), which are even more than the total risks caused by n-PAHs (3.59 × 10^-7 for male, 1.66 × 10^-6 for female). Results from this study highlighted the environment and health effects of PAHs originated from residential coal combustion, and proposed an effective way by using clean coal to alleviate the associated negative impacts.

Collocated comparisons of continuous and filter-based PM2.5 measurements at Fort McMurray, Alberta, Canada

Collocated comparisons for three PM(2.5) monitors were conducted from June 2011 to May 2013 at an air monitoring station in the residential area of Fort McMurray, Alberta, Canada, a city located in the Athabasca Oil Sands Region. Extremely cold winters (down to approximately -40°C) coupled with low PM(2.5) concentrations present a challenge for continuous measurements. Both the tapered element oscillating microbalance (TEOM), operated at 40°C (i.e., TEOM(40)), and Synchronized Hybrid Ambient Real-time Particulate (SHARP, a Federal Equivalent Method [FEM]), were compared with a Partisol PM(2.5) U.S. Federal Reference Method (FRM) sampler. While hourly TEOM(40) PM(2.5) were consistently ~20-50% lower than that of SHARP, no statistically significant differences were found between the 24-hr averages for FRM and SHARP. Orthogonal regression (OR) equations derived from FRM and TEOM(40) were used to adjust the TEOM(40) (i.e., TEOM(adj)) and improve its agreement with FRM, particularly for the cold season. The 12-year-long hourly TEOM(adj) measurements from 1999 to 2011 based on the OR equations between SHARP and TEOM(40) were derived from the 2-year (2011-2013) collocated measurements. The trend analysis combining both TEOM(adj) and SHARP measurements showed a statistically significant decrease in PM(2.5) concentrations with a seasonal slope of -0.15 μg m(-3) yr(-1) from 1999 to 2014.

IMPLICATIONS

Consistency in PM(2.5) measurements are needed for trend analysis. Collocated comparison among the three PM(2.5) monitors demonstrated the difference between FRM and TEOM, as well as between SHARP and TEOM. The orthogonal regressions equations can be applied to correct historical TEOM data to examine long-term trends within the network.

PM2.5 source apportionment with organic markers in the Southeastern Aerosol Research and Characterization (SEARCH) study

Positive matrix factorization (PMF) and effective variance (EV) solutions to the chemical mass balance (CMB) were applied to PM(2.5) (particulate matter with an aerodynamic diameter <2.5 μm) mass and chemically speciated measurements for samples taken from 2008 to 2010 at the Atlanta, Georgia, and Birmingham, Alabama, sites. Commonly measured PM(2.5) mass, elemental, ionic, and thermal carbon fraction concentrations were supplemented with detailed nonpolar organic speciation by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Source contribution estimates were calculated for motor vehicle exhaust, biomass burning, cooking, coal-fired power plants, road dust, vegetative detritus, and secondary sulfates and nitrates for Atlanta. Similar sources were found for Birmingham, with the addition of an industrial source and the separation of biomass burning into open burning and residential wood combustion. EV-CMB results based on conventional species were qualitatively similar to those estimated by PMF-CMB. Secondary ammonium sulfate was the largest contributor, accounting for 27-38% of PM(2.5), followed by biomass burning (21-24%) and motor vehicle exhaust (9-24%) at both sites, with 4-6% of PM(2.5) attributed to coal-fired power plants by EV-CMB. Including organic compounds in the EV-CMB reduced the motor vehicle exhaust and biomass burning contributions at both sites, with a 13-23% deficit for PM(2.5) mass. The PMF-CMB solution showed mixing of sources within the derived factors, both with and without the addition of speciated organics, as is often the case with complex source mixtures such as those at these urban-scale sites. The nonpolar TD-GC/MS compounds can be obtained from existing filter samples and are a useful complement to the elements, ions, and carbon fractions. However, they should be supplemented with other methods, such as TD-GC/MS on derivitized samples, to obtain a wider range of polar compounds such as sterols, sugars, and organic acids. The PMF and EV solutions to the CMB equations are complementary to, rather than replacements for, each other, as comparisons of their results reveal uncertainties that are not otherwise evident.

IMPLICATIONS

Organic markers can be measured on currently acquired PM(2.5) filter samples by thermal methods. These markers can complement element, ion, and carbon fraction measurements from long-term speciation networks. Applying the positive matrix factorization and effective variance solutions for the chemical mass balance equations provides useful information on the accuracy of the source contribution estimates. Nonpolar compounds need to be complemented with polar compounds to better apportion cooking and secondary organic aerosol contributors.