Particulate Matter Emission Factors Research Articles

Emission Factors of NOx, SO2, and PM for Bathing, Heating, Power Generation, Coking, and Cement Industries in Shanxi, China: Based on Field Measurement

Despite rapid development in China, small-scale boilers (SCBs) still occupy a prominent place in industry. Due to the lack of pollutant removal devices (RDs), SCBs emit large quantities of pollutants, which merit increased attention. In this study, various SCBs (operating on coal, gangue, coke oven gas, coal gas, and natural gas) used in bathing, heating, power generation, and coke and cement making were investigated for their SO2, NOx, and PM emission factors (EFs). The EFs were expressed as the emitted pollutant mass associated with fuel consumption (EFI), product yield (EFII), industrial output (EFIII), and power generation (EFIV). Of 17 civil SCBs, 4, 14, and 10 were not equipped with PM, NOx, and SO2 RDs, respectively. Generally, the EFI values for all of the SCBs decreased with increasing coal consumption. The averaged NOx EFI value for the 3 SCBs with installed NOx RDs was 2.00 kg t–1 versus 3.16 kg t–1 for the 17 SCBs. The sulfur content of the coal and the SO2 removal rate were highly influential factors for the SO2 EFI values. The 4 SCBs without PM RDs possessed an average EFI value of 23.9 kg t–1, which was higher than the corresponding 5.41 kg t–1 for the 13 boilers equipped with PM RDs. The EFI, EFII, and EFIV values for 9 coal-fired power plants (PPs) exhibited the same trends, decreasing as the capacity of the PPs increased from 6 to 330 MW, although slightly higher EFs were found for 600 MW plants compared to 330 MW plants. The gas-fired PPs possessed higher NOx EFs than both the coal- and gangue-fired plants, and the gangue-fired PPs displayed significantly higher EFs than coal-fired PPs with the same individual block power capacity. Because flue gas produced in the coking factories was not fully emitted during the combustion process, no correlation existed between the EFs (expressed as EFII and EFIII) and coke production or industrial output. Moreover, due to the lack of NOx RDs, the EFs of NOx were higher than those of SO2 and PM in the coking industry. Among 6 small- and medium-sized cement companies, the factories with lower cement production possessed higher EFI values for PM. A reverse trend was exhibited by the NOx EFI, however, with high combustion temperatures at factories with high production being the possible explanation.

A study of air pollution by exhaust gases from cars in well courtyards of Saint Petersburg

Abstract Pollution of the environment by exhaust gases while parking in enclosed well courtyards of Saint Petersburg is studied. A method for the assessment of extremely dangerous air pollution by CO, CH, NO x , and PM pollutants upon engine start-up and warm-up under conditions of limited air exchange is developed. Experiments involving 13 petrol and 2 diesel passenger cars of Euro 0, 3, 4, 5 emission standards were conducted. To measure the concentration of pollutants, the following gas analyzers were used: Testo-300 XXL (Testo, Germany), PGA-200 (ZAO R&D Enterprise Elektrostandart, Russia), DUSTTRAK 8530 (TSI Incorporated, USA). Values of CO, CH, NO x , PM emission factors for passenger cars of Euro 0 – Euro 5 emission standards were determined. It has been established that upon engine warm-up (in passenger cars of Euro 0 – Euro 4 emission standards) high air pollution with carbon monoxide, hydrocarbons and nitrogen oxide is formed in enclosed and poorly ventilated well courtyards in 5–10 minutes, their concentration being 2–5 times, 1.5–3 times and 1.5 times higher than the permissible levels for the Russian Federation, respectively (at the height of 2 m, i.e. at the breathing level).

Open burning of rice, corn and wheat straws: primary emissions, photochemical aging, and secondary organic aerosol formation

Abstract. Agricultural residues are among the most abundant biomass burned globally, especially in China. However, there is little information on primary emissions and photochemical evolution of agricultural residue burning. In this study, indoor chamber experiments were conducted to investigate primary emissions from open burning of rice, corn and wheat straws and their photochemical aging as well. Emission factors of NOx, NH3, SO2, 67 non-methane hydrocarbons (NMHCs), particulate matter (PM), organic aerosol (OA) and black carbon (BC) under ambient dilution conditions were determined. Olefins accounted for > 50 % of the total speciated NMHCs emission (2.47 to 5.04 g kg−1), indicating high ozone formation potential of straw burning emissions. Emission factors of PM (3.73 to 6.36 g kg−1) and primary organic carbon (POC, 2.05 to 4.11 gC kg−1), measured at dilution ratios of 1300 to 4000, were lower than those reported in previous studies at low dilution ratios, probably due to the evaporation of semi-volatile organic compounds under high dilution conditions. After photochemical aging with an OH exposure range of (1.97–4.97) × 1010 molecule cm−3 s in the chamber, large amounts of secondary organic aerosol (SOA) were produced with OA mass enhancement ratios (the mass ratio of total OA to primary OA) of 2.4–7.6. The 20 known precursors could only explain 5.0–27.3 % of the observed SOA mass, suggesting that the major precursors of SOA formed from open straw burning remain unidentified. Aerosol mass spectrometry (AMS) signaled that the aged OA contained less hydrocarbons but more oxygen- and nitrogen-containing compounds than primary OA, and carbon oxidation state (OSc) calculated with AMS resolved O ∕ C and H ∕ C ratios increased linearly (p < 0.001) with OH exposure with quite similar slopes.

Particulate matter emissions over the oil sands regions in Alberta, Canada

Particulate matter (PM) emissions from the expanded oil sands development in Alberta are becoming a focus among the aerosol science community because of its significant negative impact on the regional air quality and climate change. Open-pit mining, petroleum coke (petcoke) dust, and the transportation of oil sands and waste materials by heavy-duty trucks on unpaved roads could release PM into the air. Incomplete combustion of fossil fuels by engines and stationary boilers leads to the formation of carbonaceous aerosols. In addition, wildfire and biogenic emissions surrounding the oil sands regions also have the potential to contribute primary PM to the ambient air. Secondary organic aerosol formation has been revealed as an important source of PM over nearby and distant areas from the oil sands regions. This review summarizes the primary PM sources and some secondary aerosol formation mechanisms that are linked to oil sands development. It also reviews the approaches that can be applied in aerosol source apportionment. Meteorological condition is an important factor that may influence the primary PM emission and secondary aerosol formation in Alberta’s oil sands regions. Current concern should not be limited to the primary emission of atmospheric PM. Secondary formation of aerosols, especially secondary organic aerosol originating from photochemical reaction, should also be taken into consideration. To obtain a more comprehensive understanding of the sources and amount of PM emissions based on the bottom-up emission inventory approach, investigations on how to reduce the uncertainty in determination of real-world PM emission factors for the variable sources are needed. Long-range transport trajectories of fine PM from Alberta’s oil sands regions remain unknown.

On-board measurements of particle and gaseous emissions from a large cargo vessel at different operating conditions

This study investigated particle and gaseous emission factors from a large cargo vessel for her whole voyage including at berth, manoeuvring and cruising. Quantification of these factors assists in minimising the uncertainty in the current methods of exhaust gas emission factor estimation. Engine performance and emissions from the main marine engine were measured on-board while the ship was manoeuvring and cruising at sea. Emissions of an auxiliary engine working at 55% of maximum continuous rating (MCR) were measured when the ship was at actual harbour stopovers. Gaseous and particle emission factors in this study are presented in g kWh−1 or # kWh−1, and compared with previous studies. Results showed that the SO2 emission factor is higher than that of previous studies due to the high sulphur content of the fuel used. The particle number size distributions showed only one mode for different operating conditions of the ship, with a peak at around 40–50 nm, which was dominated by ultrafine particles. Emission factors of CO, HC, PM and PN observed during ship manoeuvring were much higher than that of those recorded at cruising condition. These findings highlight the importance of quantification and monitoring ship emissions in close proximity to port areas, as they can have the highest impact on population exposure.

Low-cost methodology to estimate vehicle emission factors

Road traffic emission factors (EFs) are important parameters in managing air quality. Estimation typically requires data from advanced (and expensive) monitoring systems which remain unavailable in some regions (e.g. in developing countries). In this context, the use of simpler (lower-cost) systems may be more appropriate, but it is essential to guarantee the robustness of EF estimations. This article describes a methodology designed to estimate vehicle EFs from street canyon measurements of traffic fluxes, wind speed and direction, and pollutant concentration levels by using low-cost devices, all samples at a one-minute interval. We use different moving window filters (time periods) to average the raw measurements. Applying standard multiple linear regressions (MRL) and principal component regressions (PCR), we show that there is an optimal smoothing level that best relates traffic episodes and pollutant concentration measurements. An application for PM10's EFs on four vehicle categories of Havana's fleet shows a preference for PCR over MLR techniques since it reduced the collinearity effects that appear when traffic fluxes are naturally correlated between vehicle categories. The best regression fits (R > 0.5 and standard deviation of estimates < 15%) were obtained by averaging data between 40′ and 60’; within the boundaries of 95% confidence interval motorcycles have an EF = 111.1 ± 2.7 mg km−1 veh−1; modern, light vehicles have an EF = 90.6 ± 11.2 mg km−1 veh−1; old, light vehicles have an EF = 125.4 ± 18.5 mg km−1 veh−1 and heavy vehicles have an EF = 415.1 ± 31.2 mg km−1 veh−1. We showed that upgrading old light vehicles is a promising scenario for reducing PM10 air pollution in Havana by between 10 and 17%.

Emission characterization of particulate matter in the ironmaking process

ABSTRACTThe study is to provide a detailed physical and chemical characterization of particles collected in the ironmaking process, including a bunker system, a cast house and a pulverized coal feeding system. Using gravimetric, scanning electron microscope coupled with energy dispersive X-ray spectrometry (SEM-EDS), X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES) analyses, the size distribution, morphology, elemental composition and emission factor of particles were investigated. The contribution rates of cast house for emission factors of total suspended particulates (TSP), PM10 and PM2.5 are the largest, 57.0%, 75.5% and 83.3%, respectively. SEM-EDS analysis indicated that cast house particle shapes are mainly formed by polymerization from spherical particles and ultrafine particles, whose main component is Fe. But, the particles of the bunker system or the pulverized coal feeding system are mainly the large ones of irregular block or powder particles and the main component is carbon. The highest content of the element in particles of the bunker system and cast house is Fe, followed by C, Si, Ca and Al. The main elements of particles in the pulverized coal feeding system are C, Si, Al and Ca, and their contents are 63.6%, 7.83%, 3.07% and 1.47%, respectively.

Lidar equation inversion methods and uncertainties in measuring fugitive particulate matter emission factors.

Measurements from two field campaigns that employed a micropulse lidar are used to compare the near-end and the far-end lidar equation inversion methods for estimating emission factors (EFs) of particulate matter (PM) from three types of anthropogenic fugitive sources: vehicles moving on unpaved roads, open burning, and open detonation. As optical depth increased from 0 to 2, relative EF uncertainty increased from 54% to 300% using the near-end method and decreased from 69% to 42% using the far-end method. To the best of our knowledge, this research is the first to use field measurements to compare results from these methods for anthropogenic PM plumes and quantify their uncertainties.

Evaluation of emission factors for light-duty gasoline vehicles based on chassis dynamometer and tunnel studies in Shanghai, China

CO, THC, NOx, and PM emission factors of 51 light-duty gasoline vehicles (LDGVs) spanning the emission standards from Euro 2 to Euro 5 were measured by a chassis dynamometer. High frequencies of high-emitting vehicles were observed in Euro 2 and Euro 3 LDGV fleet. 56% and 33% of high-emitting vehicles contributed 81%–92% and 82%–85% of the emissions in Euro 2 and Euro 3 test fleet, respectively. Malfunctions of catalytic convertors after high strength use are the main cause of the high emissions. Continuous monitoring of a gasoline vehicle dominated tunnel in Shanghai, China was conducted to evaluate the average emission factors of vehicles in real-world. The results indicated that the emission factors of LDGVs were considerably underestimated in EI guidebook in China. The overlook of high-emitting vehicles in older vehicle fleet is the main reason for this underestimation. Enhancing the supervision of high emission vehicles and strengthening the compliance tests of in-use vehicles are essential measures to control the emissions of in-use gasoline vehicles at the present stage in China.

Characterizing emissions from open burning of military food waste and ration packaging compositions.

Emissions from open burning of military food waste and ration packaging compositions were characterized in response to health concerns from open burning disposal of waste, such as at military forward operating bases. Emissions from current and prototype Meals, Ready-to-Eat (MREs), and material options for their associated fiberboard packaging were quantified to assess contributions of the individual components. MREs account for 67-100% of the particulate matter (PM), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzo-p-dioxins and -furans (PCDDs/PCDFs) emissions when burned in unison with the current fiberboard container and liner. The majority of the particles emitted from these burns are of median diameter 2.5 μm (PM2.5). Metal emission factors were similar regardless of waste composition. Measurements of VOCs and PAHs indicate that targeted replacement of MRE components may be more effective in reducing emissions than variation of fiberboard-packaging types. Despite MRE composition variation, equivalent emission factors for PM, PAH, VOC, and PCDD/PCDF were seen. Similarly, for fiberboard packaging, composition variations exhibited essentially equivalent PM, PAH, VOC, and PCDD/PCDF emission factors amongst themselves. This study demonstrated a composition-specific analysis of waste burn emissions, assessing the impact of waste component substitution using military rations.

Black carbon cookstove emissions: A field assessment of 19 stove/fuel combinations

Black carbon (BC) emissions from household cookstoves consuming solid fuel produce approximately 25 percent of total anthropogenic BC emissions. The short atmospheric lifetime of BC means that reducing BC emissions would result in a faster climate response than mitigating CO2 and other long-lived greenhouse gases. This study presents the results of optical BC measurements of two new cookstove emissions field assessments and 17 archived cookstove datasets. BC was determined from attenuation of 880 nm light, which is strongly absorbed by BC, and linearly related between 1 and 125 attenuation units. A relationship was experimentally determined correlating BC mass deposition on quartz filters determined via thermal optical analysis (TOA) and on PTFE and quartz filters using transmissometry, yielding an attenuation cross-section (σATN) for both filter media types. σATN relates TOA measurements to optical measurements on PTFE and quartz (σATN(PTFE) = 13.7 cm−2 μg, R2 = 0.87, σATN(Quartz) = 15.6 cm−2 μg, R2 = 0.87). These filter-specific σATN, optical measurements of archived filters were used to determine BC emission factors and the fraction of particulate matter (PM) in the form of black carbon (BC/PM). The 19 stoves measured fell into five stove classes; simple wood, rocket, advanced biomass, simple charcoal, and advanced charcoal. Advanced biomass stoves include forced- and natural-draft gasifiers which use wood or biomass pellets as fuel. Of these classes, the simple wood and rocket stoves demonstrated the highest median BC emission factors, ranging from 0.051 to 0.14 g MJ−1. The lowest BC emission factors were seen in charcoal stoves, which corresponds to the generally low PM emission factors observed during charcoal combustion, ranging from 0.0084 to 0.014 g MJ−1. The advanced biomass stoves generally showed an improvement in BC emissions factors compared to simple wood and rocket stoves, ranging from 0.0031 to 0.071 g MJ−1. BC/PM ratios were highest for the advanced and rocket stoves. Potential relative climate impacts were estimated by converting aerosol emissions to CO2-equivalent, and suggest that some advanced stove/fuel combinations could provide substantial climate benefits.

Characterization of Particle and Gaseous Emissions from Marine Diesel Engines with Different Fuels and Impact of After-Treatment Technology

The International Maritime Organization (IMO) Marine Environment Protection Committee (MEPC) and some countries have gradually strengthened the laws regulating ship exhaust emissions. The aim of this paper is to estimate the impact of an after-treatment technology exhaust gas cleaning (EGC) system on marine diesel engine emissions and the cost advantage compared to using low-sulfur fuel oil. The emission characteristics of SO2 and particulate matter (PM) produced from high sulfur oil and low sulfur oil in a low-speed two-stroke marine diesel engine were also presented. The removal efficiency of SO2 has been tested and the PM removal efficiency was also predicted in this study. When using high sulfur oil, the emission factor of SO2 and PM were from 8.73 g/kWh to 11.6 g/kWh and 2.0 g/kWh to 2.7 g/kWh, respectively. These values are significantly higher than the emission values from using low sulfur oil. The fuel sulfur content (FSC) was the key factor affecting the emission factors of SO2 and PM. The fuel change could reduce the mass emission factor of PM, which is above 90% for the total particle emission with the two fuels. When using the EGC system, the desulfurization efficiencies were above 99%. The pH values at a 25, 39, 53, and 67% load were also stabilized to be around 7.5, 7.6, 7.7, and 8, respectively. The EGC system can also capture part of the primary PM and secondary PM formed from SO2. The EGC system was more effective for PM of the size larger than 1 μm. Thus, according to this study, the usage of low sulfur oil and EGC will also substantially decrease the emission of currently unregulated hazardous chemical species in the exhaust gas of ships in addition to satisfying future emissions regulations of ship. Furthermore, the EGC system also had a significant cost advantage compared to using low-sulfur fuel oil.

Primary and Photochemically Aged Aerosol Emissions from Biomass Cookstoves: Chemical and Physical Characterization

Secondary organic aerosol (SOA) formation during photo-oxidation of primary emissions from cookstoves used in developing countries may make important contributions to their climate and air quality impacts. We present results from laboratory experiments with a field portable oxidation flow reactor (F-OFR) to study the evolution of emissions over hours to weeks of equivalent atmospheric aging. Lab tests, using dry red oak, measured fresh and aged emissions from a 3 stone fire (TSF), a "rocket" natural draft stove (NDS), and a forced draft gasifier stove (FDGS), in order of increasing modified combustion efficiency (MCE) and decreasing particulate matter emission factors (EF). SOA production was observed for all stoves/tests; organic aerosol (OA) enhancement factor ranged from 1.2 to 3.1, decreasing with increased MCE. In primary emissions, OA mass spectral fragments associated with oxygenated species (primary biomass burning markers) increased (decreased) with MCE; fresh OA from FDGS combustion was especially oxygenated. OA oxygenation increased with further oxidation for all stove emissions, even where minimal enhancement was observed. More efficient stoves emit particles with greater net direct specific warming than TSFs, with the difference increasing with aging. Our results show that the properties and evolution of cookstove emissions are a strong function of combustion efficiency and atmospheric aging.

Emission factors of fine particulate matter, organic and elemental carbon, carbon monoxide, and carbon dioxide for four solid fuels commonly used in residential heating by the U.S. Navajo Nation

ABSTRACTMost homes in the Navajo Nation use wood as their primary heating fuel, often in combination with locally mined coal. Previous studies observed health effects linked to this solid-fuel use in several Navajo communities. Emission factors (EFs) for common fuels used by the Navajo have not been reported using a relevant stove type. In this study, two softwoods (ponderosa pine and Utah juniper) and two high-volatile bituminous coals (Black Mesa and Fruitland) were tested with an in-use residential conventional wood stove (homestove) using a modified American Society for Testing and Materials/U.S. Environmental Protection Agency (ASTM/EPA) protocol. Filter sampling quantified PM2.5 (particulate matter with an aerodynamic diameter ≤2.5 μm) and organic (OC) and elemental (EC) carbon in the emissions. Real-time monitoring quantified carbon monoxide (CO), carbon dioxide (CO2), and total suspended particles (TSP). EFs for these air pollutants were developed and normalized to both fuel mass and energy consumed. In general, coal had significantly higher mass EFs than wood for all pollutants studied. In particular, coal emitted, on average, 10 times more PM2.5 than wood on a mass basis, and 2.4 times more on an energy basis. The EFs developed here were based on fuel types, stove design, and operating protocols relevant to the Navajo Nation, but they could be useful to other Native Nations with similar practices, such as the nearby Hopi Nation.Implications: Indoor wood and coal combustion is an important contributor to public health burdens in the Navajo Nation. Currently, there exist no emission factors representative of Navajo homestoves, fuels, and practices. This study developed emission factors for PM2.5, OC, EC, CO, and CO2 using a representative Navajo homestove. These emission factors may be utilized in regional-, national-, and global-scale health and environmental models. Additionally, the protocols developed and results presented here may inform on-going stove design of the first EPA-certified wood and coal combination stove.

Emission factors of health- and climate-relevant pollutants measured in home during a carbon-finance-approved cookstove intervention in rural India.

We present results of an emission characterization effort, completed as part of a larger intervention trial, of a carbon‐finance‐approved program replacing traditional cookstoves with “rocket”‐style natural draft stoves. The 100 emission tests were conducted across 31 households in control and intervention groups, with repeated tests in most households during preintervention and postintervention periods. While mean fine particulate matter (PM2.5) emission factor for intervention stoves was significantly lower than for traditional stoves in baseline measurements, they were only marginally lower than traditional stoves during follow‐up. Intervention stove PM2.5 emissions had a larger contribution from light‐absorbing (elemental) carbon than traditional stoves. Repeated measurements in control households provide evidence for strong seasonality, likely due to differences in fuel moisture/types, in traditional stove emissions, with important implications for study design. Seasonality observed in control household emission factors (baseline > follow‐up) was in the opposite direction as that observed in indoor PM2.5 concentrations (baseline < follow‐up), highlighting that seasonally varying conditions (e.g., ventilation rates) may modify the link between emissions and exposures. Emission factor differences in paired (pre/post) tests from the same households were similar to differences in the medians of entire groups, suggesting variability is dominated by test‐to‐test variation. Emission reductions from intervention stoves were significantly smaller than laboratory performance would suggest or that are required to strongly reduce exposures. Field emissions assessment like that presented here should be prioritized early in technology assessment and development to provide rigorous estimates of the benefits reasonably expected from interventions with the potential for substantial benefits to human health and the environment.

Emissions from prescribed burning of agricultural fields in the Pacific Northwest

Prescribed burns of winter wheat stubble and Kentucky bluegrass fields in northern Idaho and eastern Washington states (U.S.A.) were sampled using ground-, aerostat-, airplane-, and laboratory-based measurement platforms to determine emission factors, compare methods, and provide a current and comprehensive set of emissions data for air quality models, climate models, and emission inventories. Batch measurements of PM2.5, volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and polychlorinated dibenzodioxins/dibenzofurans (PCDDs/PCDFs), and continuous measurements of black carbon (BC), particle mass by size, CO, CO2, CH4, and aerosol characteristics were taken at ground level, on an aerostat-lofted instrument package, and from an airplane. Biomass samples gathered from the field were burned in a laboratory combustion facility for comparison with these ground and aerial field measurements. Emission factors for PM2.5, organic carbon (OC), CH4, and CO measured in the field study platforms were typically higher than those measured in the laboratory combustion facility. Field data for Kentucky bluegrass suggest that biomass residue loading is directly proportional to the PM2.5 emission factor; no such relationship was found with the limited wheat data. CO2 and BC emissions were higher in laboratory burn tests than in the field, reflecting greater carbon oxidation and flaming combustion conditions. These distinctions between field and laboratory results can be explained by measurements of the modified combustion efficiency (MCE). Higher MCEs were recorded in the laboratory burns than from the airplane platform. These MCE/emission factor trends are supported by 1–2 min grab samples from the ground and aerostat platforms. Emission factors measured here are similar to other studies measuring comparable fuels, pollutants, and combustion conditions. The size distribution of refractory BC (rBC) was single modal with a log-normal shape, which was consistent among fuel types when normalized by total rBC mass. The field and laboratory measurements of the Angstrom exponent (α) and single scattering albedo (ω) exhibit a strong decreasing trend with increasing MCEs in the range of 0.9–0.99. Field measurements of α and ω were consistently higher than laboratory burns, which is likely due to less complete combustion. When VOC emissions are compared with MCE, the results are consistent for both fuel types: emission factors increase as MCE decreases.

Differences between emissions measured in urban driving and certification testing of heavy-duty diesel engines

Emissions from eight heavy-duty diesel trucks (HDDTs) equipped with three different exhaust aftertreatment systems (ATS) for controlling nitrogen oxide (NOx) emissions were quantified on a chassis dynamometer using driving schedules representative of stop-and-go and free-flow driving in metropolitan areas. The three control technologies were: 1) cooled exhaust gas recirculation (CEGR) plus a diesel particulate filter (DPF); 2) CEGR and DPF plus advanced engine controls; and 3) CEGR and DPF plus selective catalytic reduction with ammonia (SCR). Results for all control technologies and driving conditions showed PM emission factors were less than the standard, while selected non-regulated emissions (ammonia, carbonyls, and C4–C12 hydrocarbons) and a greenhouse gas (nitrous oxide) were at measurement detection limits. However, NOx emission factors depended on the control technology, engine calibration, and driving mode. For example, emissions from engines with cooled-exhaust gas recirculation (CEGR) were 239% higher for stop-and-go driving as compared with free-flow. For CEGR plus selective catalytic reduction (SCR), the ratio was 450%. A deeper analysis was carried out with the assumption that emissions measured for a drive cycle on either the chassis or in-use driving would be similar. Applying the same NTE rules to the chassis data showed emissions during stop-and-go driving often exceeded the certification standard and >90% of the driving did not fall within the Not-To-Exceed (NTE) control area suggesting the NTE requirements do not provide sufficient emissions control under in-use conditions. On-road measurement of emissions using the same mobile lab while the vehicle followed a free-flow driving schedule verified the chassis results. These results have implications for scientists who build inventories using certification values instead of real world emission values and for metropolitan populations, who are exposed to elevated emissions. The differences in values between real world emissions and certification cycles should be narrowed. For example, one might use a different mix of cold and hot start testing to greater emphasize low temperature/load operation, a separate cycle to specifically characterize low-load operation, or broaden the in-use compliance testing requirements and associated conformity factors to incorporate a wider envelope of vehicle operation, especially at low load conditions. .

The effects of biodiesels on semivolatile and nonvolatile particulate matter emissions from a light-duty diesel engine

Semivolatile organic compounds (SVOCs) represent a dominant category of secondary organic aerosol precursors that are increasingly included in air quality models. In the present study, an experimental system was developed and applied to a light-duty diesel engine to determine the emission factors of particulate SVOCs (pSVOCs) and nonvolatile particulate matter (PM) components at dilution ratios representative of ambient conditions. The engine was tested under three steady-state operation modes, using ultra-low-sulfur diesel (ULSD), three types of pure biodiesels and their blends with ULSD. For ULSD, the contribution of pSVOCs to total particulate organic matter (POM) mass in the engine exhaust ranged between 21 and 85%. Evaporation of pSVOCs from the diesel particles during dilution led to decreases in the hydrogen to carbon ratio of POM and the PM number emission factor of the particles. Substituting biodiesels for ULSD could increase pSVOCs emissions but brought on large reductions in black carbon (BC) emissions. Among the biodiesels tested, tallow/used cooking oil (UCO) biodiesel showed advantages over soybean and canola biodiesels in terms of both pSVOCs and nonvolatile PM emissions. It is noteworthy that PM properties, such as particle size and BC mass fraction, differed substantially between emissions from conventional diesel and biodiesels.

Measurement of PM and its chemical composition in real-world emissions from non-road and on-road diesel vehicles

Abstract. With the rapid growth in the number of both non-road and on-road diesel vehicles, the adverse effects of particulate matter (PM) and its constituents on air quality and human health have attracted increasing attentions. However, studies on the characteristics of PM and its composition emitted from diesel vehicles are still scarce, especially under real-world driving conditions. In this study, six excavators and five trucks that provided a wide range of emission standards and operation modes were tested, and PM emissions and their constituents – including organic carbon (OC), elemental carbon (EC), water-soluble ions (WSIs), elements, and organic species like polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes – as well as steranes were analyzed and characterized. The average emission factors for PM (EFPM) from excavator and truck emissions were 829 ± 806 and 498 ± 234 mg kg−1 fuel, respectively. EFPM and PM constituents were significantly affected by fuel quality, operational mode, and emission standards. A significant correlation (R2 = 0. 79, p &lt; 0. 01) was found between EFPM for excavators and the sulfur contents in fuel. The highest average EFPM for working excavators was 904 ± 979 mg kg−1 fuel as a higher engine load required in this mode. From pre-stage 1 to stage 2, the average EFPM for excavators decreased by 58 %. For trucks, the average non-highway EFPM at 548 ± 311 mg kg−1 fuel was higher than the highway EFPM at 497 ± 231 mg kg−1 fuel. Moreover, the reduction rates were 63.5 and 65.6 % when switched from China II and III to China IV standards, respectively. Generally, the PM composition emitted from excavators was dominated by OC (39. 2 ± 21. 0 %) and EC (33. 3 ± 25. 9 %); PM from trucks was dominated by EC (26. 9 ± 20. 8 %), OC (9. 89 ± 12 %), and WSIs (4. 67 ± 5. 74 %). The average OC ∕ EC ratios for idling and working excavators were 3 to 4 times higher than those for moving excavators. Although the EFPM for excavators and trucks was reduced with the constraint of regulations, the element fractions for excavators increased from 0.49 % in pre-stage 1 to 3.03 % in stage 2, and the fraction of WSIs for the China IV truck was 5 times higher than the average value of all other-level trucks. Furthermore, as compared with other diesel vehicles, wide ranges were found for excavators of the ratios of benzo[a]anthracene ∕ (benzo[a]anthracene + chrysene) (0.26–0.86), indeno[1,2,3-cd]pyrene ∕ (indeno[1,2,3-cd]pyrene + benzo[ghi]perylene) (0.20–1.0), and fluoranthene ∕ (fluoranthene + pyrene) (0.24–0.87), which might be a result of the complex characteristics of the excavator operation modes. A comparison of our results with those in the literature revealed that on-board measurement data more accurately reflect actual conditions. Although the fractions of the 16 priority PAHs in PM from the excavator and truck emissions were similar, the equivalent concentrations of total benzo[a]pyrene of excavators were 31 times than that for trucks, implying that more attention should be paid to non-road vehicle emissions.

Back-Calculation of Traffic-Related PM10 Emission Factors Based on Roadside Concentration Measurements

Many researchers have failed to utilize back-calculation to estimate traffic emissions effectively or have obtained unclear results. In this study, the back-calculation of traffic-related PM10 emission factors based on roadside concentration measurements was analyzed. Experimental conditions were considered to ensure the success of back-calculation. Roadside measurements were taken in a street canyon in Shanghai, China. Concentrations from a background site were often found to exceed the measured concentrations at the roadside on polluted days as more errors occurred in the background concentrations. On clean days, these impacts were negligible. Thus, only samples collected on clean days were used in back-calculation. The mean value from back-calculation was 0.138 g/km, which was much smaller than the results obtained using official emission models. Emission factors for light-duty vehicles (LDV), medium-duty vehicles (MDV), heavy-duty vehicles (HDV), and motorcycles were approximately 0.121, 0.427, 0.445, and 0.096 g/km, respectively. The fleet-averaged non-exhaust emission factor was approximately 0.121 g/km, indicating that road dust accounted for 87.7% of the roadside concentration increments. According to the dispersion simulation of reserved samples, the concentrations simulated using back-calculated emission factors were in better agreement with the measured data than the concentrations derived using modeled emission factors.