Black Carbon Particulate Matter Research Articles

Variations in levels of Black Carbon particulate matter by walkways and time of day in New York City

Variations in levels of Black Carbon particulate matter by walkways and time of day in New York City

Balancing energy security and marine pollution prevention: legal challenges of utilizing nuclear power for decarbonizing maritime transportation in the Arctic region.

The Arctic region is facing growing demands for energy to support various economic activities, while also grappling with the profound impacts of climate change. Black carbon particulate matter emissions reduction is a key objective to mitigate the susceptibility of the Arctic's ecosystems to the impact of climate change. Nuclear power has been suggested as a potential source of clean energy to decarbonize maritime transport in the Arctic. However, although the operation of nuclear-powered vessels and floating nuclear power platforms in the region ensures energy security and reduces black carbon emissions, it may pose significant risks of nuclear material release and radiological accidents and raise concerns about improper radioactive waste disposal. In regulating these nuclear-powered vessels and floating nuclear power platforms in the Arctic, the existing international legal regime faced a series of challenges. This research employs a method of policy analysis to analyze these legal challenges and explores how the international community could work together to cope with the challenges that arise in the Arctic during the operation of nuclear-powered vessels and platforms for maritime decarbonization purposes.

Impact of traffic congestion on near-road black carbon particulate matter and nitric oxide levels

Impact of traffic congestion on near-road black carbon particulate matter and nitric oxide levels

Joint effect of indoor size-fractioned particulate matters and black carbon on cardiopulmonary function and relevant metabolic mechanism: A panel study among school children

Indoor particulate matter (PM) and black carbon (BC) are associated with adverse cardiopulmonary effect. However, the cumulative and interactive effects of the mixture of size-fractioned PMs and BC on cardiopulmonary function are not well understood, and the underlying biological mechanisms remain unclear. This repeated-measure study was conducted to assess the joint cardiopulmonary effect and metabolic mechanisms of multiple-size particles and BC among 46 children. PM0.5, PM1, PM2.5, PM5, PM10 and BC were monitored for 5 weekdays. Cardiorespiratory function measurements and urine samples collection were conducted three times. Untargeted-metabolomics and meet-in-metabolite approach were applied to mechanism investigation. Bayesian machine kernel regression was adopted to analyze associations among PMs, cardiopulmonary function and metabolites. Lung function and heart rate variability significantly decreased with the increased PMs and BC co-exposure (p < 0.05). The effective particles were BC, PM1-2.5 and PM0.5 in turn. No interaction effects of different particles on cardiopulmonary function were observed at different lag days. BC-related glucose and fatty acid increase, and PM1-2.5-related branched-chain amino acid degradation were primarily observed. Other metabolisms were successively disturbed. The greatest joint effects of PMs and BC on metabolism were mainly at lag0 and lag01 day. They occurred earlier than the strongest effects on cardiopulmonary function, which were at lag01 and lag02 day. BC, PM1-2.5 and PM0.5 were mainly associated with cardiorespiratory indices by disturbing amino acids, glucose, lipid, isoflavone and purine metabolism. Mitochondrial productivity and antioxidation reduction are pivotal to the relevant metabolic alterations. More attention should be paid to BC and smaller-size PMs to control indoor PM pollution and its adverse effect on children.

Corona Discharge Characteristics in Electrostatic Precipitator Under High Temperature

Harmful substances, such as particulate matter (PM), nitrogen oxides, and sulfur compounds in exhaust gas emitted from marine diesel engines have a great impact on the air environment. Among them, especially black carbon in PM has a negative effect on global warming. The exhaust gas from marine diesel engines using fuels containing heavy fuel oil has a high PM concentration and high temperature. Therefore, a commonly used diesel particulate filter is not suitable for collection because it tends to cause clogging and reduce efficiency. Furthermore, it is often the case that ships are at sea for more than one month, so it is difficult to replace the filter, that is, maintenance is difficult. On the other hand, an electrostatic precipitator (ESP) has the advantages of a simpler structure, lower pressure loss, and higher collection efficiency of high concentration particles. This suggests that the ESP is suitable for collecting harmful substances from the marine diesel exhaust gas. At high temperatures, corona discharge is unstable, and a flashover tends to occur at low applied voltage. Therefore, it is necessary to study the stable corona discharge generation range for the stable operation of the ESP. The purpose of this research is to analyze the optimal electrode structure and its corona discharge characteristics under the simulated exhaust gas of a diesel engine in the range of 100 °C – 400 °C using a negative dc power supply.

A New PM Sampler with a Built-In Black Carbon Continuous Monitor

We introduce a new instrument for sampling the airborne particulate matter (PM) while monitoring the black carbon (BC) atmospheric concentration. The concentration of PM and BC are usually measured by separate instruments with possible systematics differences even in the collecting inlets. The new equipment is based on a low-volume sequential PM sampler, fully compliant with the EU-CEN and US-EPA regulatory standards, with a built-in optical BC monitor. The BC concentration is continuously measured during the sampling in the PM accumulated on the filter while the PM concentration can be obtained off-line by a standard gravimetric analysis. The optical set-up, upstream the collecting filter, is composed by a single wavelength light source (λ = 635 nm) and a photodiode, placed in way to receive the light backscattered by the filter surface at a fixed angle. The mechanical arrangement does not introduce any perturbation to the PM sampling. Thanks to an original calibration curve, the sample absorbance is deduced from the output signal of the photodiode. Finally, the BC concentration is obtained through the Mass Absorption Coefficient (MAC). After the sampling and the PM gravimetric determination, the same filter can be sent to other compositional analyses. Thermo-optical quantification of the Elemental and Organic Carbon (EC and OC) in the filter sample can thus be exploited to tune the MAC value to the PM composition of a particular site. The main features of the new instrument and the set of validation tests against other PM samplers and BC monitors of widespread use (i.e.,: Multi Angle Absorption Photometer and aethalometer) are detailed and discussed.

Closure between particulate matter concentrations measured ex situ by thermal–optical analysis and in situ by the CPMA–electrometer reference mass system

The thermal-optical analysis (TOA) of black carbon in particulate matter (PM) collected on filters has been recommended and used for the calibration of mass-concentration instruments. However, filt...

The contribution of moped emissions to ultrafine and fine particle concentrations on bike lanes

Although not emitting air pollution themselves, cyclists are exposed to air pollution from motorised traffic. Because of the close proximity of mopeds to cyclists, moped emissions may affect cyclist exposure. However, the quantitative contribution of mopeds to cyclists' air pollution exposures is uncertain. The aim of the research was to quantify the contribution of moped emissions to air pollution concentrations on bike lanes.Measurements of Particle Number Concentrations (PNC),11PNC = Particle Number Count Particulate Matter (PM)22PM = Particulate Matter and Black Carbon (BC)33BC = Black Carbon on bike lanes were performed in September 2016 in four Dutch cities. Passing two- and four-stroke mopeds and other traffic were recorded and distinguished by sound by the trained field worker. One-second PNC, PM and one-minute BC concentrations were measured. Using regression analyses the contribution of passing mopeds to air pollution exposure was analysed.At 18 non-tunnel locations, two-stroke and four-stroke mopeds contributed at average 12,000 and 3000 pt./cm3 PNC per second when passing by, respectively. In a tunnel, this was 92,000 and 12,000 pt./cm3. Two- and four-strokes added 3 to 19% to total PNC at non-tunnel sites and 58% in a tunnel. Four-strokes caused at average 54% of the contribution of moped emissions to total PNC. At non-tunnel sites, the contribution of mopeds to PM was 1.2 and 0.2 μg/m3 for two- and four-strokes, respectively. In a tunnel this was 3.9 and 2.3 μg/m3. Minute-measurements of BC did not show a relation between mopeds passing by and BC.Mopeds caused substantial short-term increases in air pollution levels on bike lanes, especially in a tunnel. Two-stroke mopeds caused higher concentration peaks than four-stroke mopeds. The contribution to total air pollution concentrations of four-stroke mopeds was larger, because of the higher share of four-strokes. Because of the close proximity of mopeds to cyclists, cyclists air pollution exposure can be largely influenced by moped emissions.

Crop burning pollutes Delhi’s urban air

Air pollution spreads not just from urban areas to rural ones. Rural activities can also pollute urban air and result in high economic costs, new studies find. Studying the source of air pollution in New Delhi, researchers found that emissions from burning crop residues or other biomass in rural areas neighboring the city contribute nearly half of the airborne black-carbon particulate matter—soot—in New Delhi during the fall and winter (Nat. Sustainability 2019, DOI: 10.1038/s41893-019-0219-0). The rest of the black-carbon pollution comes from fossil-fuel burning, such as from cars and trucks. The biomass-burning contribution drops to 20% in the summer. Reseachers from Stockholm University and the Indian Institute for Tropical Meteorology conducted the analysis. “No other study has reported high amounts of black carbon from biomass burning in the middle of a megacity where the only source should be traffic,” says August Andersson, one of the researchers from Stockholm University. “The

Source apportionment of trace elements and black carbon in an urban industrial area (Portland, Oregon)

This paper reports a current source apportionment study of trace elements and black carbon in particulate matter in industrial Southeast Portland, Oregon. The study aimed to determine whether metal pollution hotspots identified in the area in 2016 had been successfully mitigated by baghouse installation, or whether industrial sources continued to dominate local particulate matter. Particulate matter was filter-collected nearly continuously in 24-hour intervals between October 2017 and March 2018 (101 total filters). Filters were analyzed for 30 elements by x-ray fluorescence; black carbon was measured continuously during filter sampling using an aethalometer. EPA's Positive Matrix Factorization 5.0 was used for source apportionment modeling, yielding a 5-factor optimal solution. The source identities were resolved to be diesel and fuel emissions, sea salt, soil dust, secondary sulfates, and metals industry. The metals industry source was much less significant than expected, suggesting effective emissions reductions from the local factory. The source profiles' correlation with wind direction and speed using bivariate polar plots was examined to give further insight into the source identities and their locations. The NOAA HYSPLIT model was also used for air flow back-trajectory analysis. The results of the HYSPLIT and bivariate polar plots suggest that the coal power plant in eastern Oregon is a significant source of sulfates and mercury emissions. Using PMF on particulate matter data from a second industrial location in Southeast Portland (98 filters) revealed the same major sources except for the metals industry source, supporting the conclusion that regional sources dominate particulate matter metals composition, despite measurements made in an industrial urban location.

Folded tubular photometer for atmospheric measurements of NO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; and NO

Abstract. We describe and characterize a modular folded tubular photometer for making direct measurements of the concentrations of nitrogen dioxide (NO2) and specify how this method could be extended to measure other pollutants such as sulfur dioxide (SO2), ozone (O3), and black carbon particulate matter. Direct absorbance measurements using this photometer can be made across the spectral range from the ultraviolet (UV) to the near infrared. The absorbance cell makes use of modular components (tubular detection cells and mirror cubes) that allow construction of path lengths of up to 2 m or more while maintaining low cell volumes. The long path lengths and low cell volumes enable sensitive detection of ambient air pollutants down to low part-per-billion levels for gas species and aerosol extinctions down to 1 Mm−1, corresponding to ∼ 0.1 µg m−3 for black carbon particulates. Pressure equalization throughout the stages of the absorbance measurement is shown to be critical to accurate measurements of analyte concentrations. The present paper describes the application of this photometer to direct measurements of nitrogen dioxide (NO2) and the incorporation of design features that also enable measurement of nitric oxide (NO) in the same instrument. Excellent agreement for ambient measurements along an urban roadside was found for both NO2 and NO measured by the folded tubular photometer compared to existing standard techniques. Compared to commonly used methods for measurements of NOx species, the advantages of this approach include (1) an absolute quantification for NO2 based on the Beer–Lambert law, thereby greatly reducing the frequency at which calibrations are required; (2) the direct measurement of NO2 concentration without prior conversion to NO as is required for the commonly used chemiluminescence method; (3) the use of modular components that allow construction of absorbance detection cells of varying lengths for extending the dynamic range of concentrations that can be measured; (4) a more economical instrument than other currently available direct measurement techniques for NO2; and (5) the potential for simultaneous detection of additional species such as SO2, O3, and black carbon in the same instrument. In contrast to other commercially available direct NO2 measurements, such as cavity-attenuated phase-shift spectroscopy (CAPS), the folded tubular photometer also measures NO simultaneously in the same apparatus by quantitatively converting NO to NO2 with ozone, which is then detected by direct absorbance.

Ambient black carbon particulate matter in the coal region of Dhanbad, India

Light-absorbing, atmospheric particles have gained greater attention in recent years because of their direct and indirect impacts on regional and global climate. Atmospheric black carbon (BC) aerosol is a leading climate warming agent, yet uncertainties in the global direct aerosol radiative forcing remain large. Based on a year of aerosol absorption measurements at seven wavelengths, BC concentrations were investigated in Dhanbad, the coal capital of India. Coal is routinely burned for cooking and residential heat as well as in small industries. The mean daily concentrations of ultraviolet-absorbing black carbon measured at 370nm (UVBC) and black carbon measured at 880nm (BC) were 9.8±5.7 and 6.5±3.8μgm−3, respectively. The difference between UVBC and BC, Delta-C, is an indicator of biomass or residential coal burning and averaged 3.29±4.61μgm−3. An alternative approach uses the Ǻngstrom Exponent (AE) to estimate the biomass/coal and traffic BC concentrations. Biomass/coal burning contributed ~87% and high temperature, fossil-fuel combustion contributed ~13% to the annual average BC concentration. The post-monsoon seasonal mean UVBC values were 10.9μgm−3 and BC of 7.2μgm−3. Potential source contribution function analysis showed that in the post-monsoon season, air masses came from the central and northwestern Indo-Gangetic Plains where there is extensive agricultural burning. The mean winter UVBC and BC concentrations were 15.0 and 10.1μgm−3, respectively. These higher values were largely produced by local sources under poor dispersion conditions. The direct radiative forcing (DRF) due to UVBC and BC at the surface (SUR) and the top of the atmosphere (TOA) were calculated. The mean atmospheric heating rates due to UVBC and BC were estimated to be 1.40°Kday−1 and 1.18°Kday−1, respectively. This high heating rate may affect the monsoon circulation in this region.

A method for monitoring mass concentration of black carbon particulate matter using photothermal interferometry.

A method for measurements of mass concentration of black carbon particulate matter (PM) is proposed based on photothermal interferometry (PTI). A folded Jamin photothermal interferometer was used with a laser irradiation of particles deposited on a filter paper. The black carbon PM deposited on the filter paper was regarded as a film while the quartz filter paper was regarded as a substrate to establish a mathematical model for measuring the mass concentration of PM using a photothermal method. The photothermal interferometry system was calibrated and used to measure the atmospheric PM concentration corresponding to different dust-treated filter paper. The measurements were compared to those obtained using β ray method and were found consistent. This method can be particularly relevant to polluted atmospheres where PM is dominated by black carbon.

Characterization of atmospheric black carbon in particulate matter over the Monterrey metropolitan area, Mexico, using scanning electron microscopy

The Monterrey metropolitan area (MMA) had an estimated population of 3,776,621 inhabitants in 2010, representing 81 % of the population of the northeastern Mexican State of Nuevo Leon. This heavily urbanized region is characterized not only by its large commercial and industrial activities, but also by its dense suspended particulate matter (SPM) pollution. Black carbon (BC), a significant component of SPM, has been recognized as a relevant health hazard and a crucial contributor for global warming due to the high capability of absorbing sunlight and contributing to the greenhouse effect. The aim of this work was to detect, characterize, and analyze the BC content in the SPM present in the MMA by scanning electron microscopy (SEM). The standardized method may be used to assemble a dataset applicable to the development of simulated climate scenarios for the region in future years. SPM concentrations were estimated to be 96.0 ± 34.8 μg/m3. SEM analyses indicated that BC content in SPM was 1.6 ± 0.3 μg/m3, with a particle size range of 0.5–10.0 μm. It is concluded that the SPM pollution from the MMA is above the World Health Organization air quality guidelines. SPM and BC levels reported in this work position the MMA as one of the most polluted urban air areas in Latin America.

Illumination, lighting technologies, and indoor environmental quality

Illumination, lighting technologies, and indoor environmental quality

English

This work investigates the implications of natural-gas composition on the combustion in a heavy-duty natural-gas engine and on the associated pollutant emissions. Natural gas is injected in ports and mixes with air before entering the cylinder. For the ignition source, both a spark plug and diesel pilot, which is injected before the top-dead center in the cylinder, are used. The effect of additives such as hydrogen, ethane and nitrogen on the output power and efficiency of the engine and emission levels are examined. The results indicate that these additives had no significant effect on the engine’s power or fuel consumption. Emissions of unburned fuel are reduced for all additives through either enhanced ignition or combustion processes. Adding ethane and H2 to the fuel increases the in-cylinder pressure and NOx emission, while fuel dilution with N2 has a critical amount. Black carbon particulate matter emissions are increased by ethane, but are virtually eliminated by including nitrogen or hydrogen in the fuel. The results show the higher flame speed of ethane compared to hydrogen, and hydrogen compared to methane. Thus, to reach the MBT condition, the spark time of ethane is the most retarded one and for methane it is the most advanced.

Black carbon particulate matter emission factors for buoyancy-driven associated gas flares

Flaring is a technique used extensively in the oil and gas industry to burn unwanted flammable gases. Oxidation of the gas can preclude emissions of methane (a potent greenhouse gas); however, flaring creates other pollutant emissions such as particulate matter (PM) in the form of soot or black carbon (BC). Currently available PM emission factors for flares were reviewed and found to be questionably accurate, or based on measurements not directly relevant to open-atmosphere flares. In addition, most previous studies of soot emissions from turbulent diffusion flames considered alkene or alkyne based gaseous fuels, and few considered mixed fuels in detail and/or lower sooting propensity fuels such as methane, which is the predominant constituent of gas flared in the upstream oil and gas industry. Quantitative emission measurements were performed on laboratory-scale flares for a range of burner diameters, exit velocities, and fuel compositions. Drawing from established standards, a sampling protocol was developed that employed both gravimetric analysis of filter samples and real-time measurements of soot volume fraction using a laser-induced incandescence (LII) system. For the full range of conditions tested (burner inner diameter [ID] of 12.7–76.2 mm, exit velocity 0.1–2.2 m/sec, 4- and 6-component methane-based fuel mixtures representative of associated gas in the upstream oil industry), measured soot emission factors were less than 0.84 kg soot/103 m3 fuel. A simple empirical relationship is presented to estimate the PM emission factor as a function of the fuel heating value for a range of conditions, which, although still limited, is an improvement over currently available emission factors. Implications Despite the very significant volumes of gas flared globally and the requirement to report associated emissions in many jurisdictions of the world, a review of the very few existing particulate matter emission factors has revealed serious shortcomings sufficient to suggest that estimates of soot production from flares based on current emission factors should be interpreted with caution. New BC emissions data are presented for laboratory-scale flares in what are believed to be the first such experiments to consider fuel mixtures relevant to associated gas compositions. The empirical model developed from these data is an important step toward being able to better predict and manage BC emissions from flaring.

The Importance of Scale for Spatial-Confounding Bias and Precision of Spatial Regression Estimators

Residuals in regression models are often spatially correlated. Prominent examples include studies in environmental epidemiology to understand the chronic health effects of pollutants. I consider the effects of residual spatial structure on the bias and precision of regression coefficients, developing a simple framework in which to understand the key issues and derive informative analytic results. When unmeasured confounding introduces spatial structure into the residuals, regression models with spatial random effects and closely-related models such as kriging and penalized splines are biased, even when the residual variance components are known. Analytic and simulation results show how the bias depends on the spatial scales of the covariate and the residual: one can reduce bias by fitting a spatial model only when there is variation in the covariate at a scale smaller than the scale of the unmeasured confounding. I also discuss how the scales of the residual and the covariate affect efficiency and uncertainty estimation when the residuals are independent of the covariate. In an application on the association between black carbon particulate matter air pollution and birth weight, controlling for large-scale spatial variation appears to reduce bias from unmeasured confounders, while increasing uncertainty in the estimated pollution effect.

The influence of fuel composition on a heavy-duty, natural-gas direct-injection engine

This work investigates the implications of natural-gas composition on the combustion in a heavy-duty natural-gas engine and on the associated pollutant emissions. In this engine system, natural gas is injected into the combustion chamber shortly before the end of the compression stroke; a diesel pilot that precedes the natural-gas injection provides the ignition source. The effects of adding ethane, propane, hydrogen, and nitrogen to the fuel are reported here. The results indicate that these additives had no significant effect on the engine’s power or fuel consumption. Emissions of unburned fuel are reduced for all additives through either enhanced ignition or combustion processes. Black carbon particulate matter emissions are increased by ethane and propane, but are virtually eliminated by including nitrogen or hydrogen in the fuel.

Direct contact cytotoxicity assays for filter-collected, carbonaceous (soot) nanoparticulate material and observations of lung cell response

A simple, direct contact, cytotoxicity (in vitro) assay has been developed where particulate matter (PM) collected on glass fiber filters was exposed to human epithelial (lung) cells. Carbonaceous (soot) PM included tire, wood, diesel, candle, and variously combusted natural gas PM from a kitchen stove range. Black carbon PM and a commercial multiwall carbon nanotube aggregate PM was also examined in vitro as surrogate materials, and all experimental PM was characterized by field emission scanning electron microscopy and transmission electron microscopy. Assay results for 48 h cultures showed toxicity for all carbonaceous PM with various natural gas PM being the most toxic; this was comparable to the toxicity induced by the surrogate PM. Light microscopy examination of affected epithelial cells confirmed the semi-quantitative results. Comparison of polycyclic aromatic hydrocarbon (PAH) content and concentration for the carbonaceous PM showed no PAH correlation with relative cell viability (cell death) after 48 h.