Particulate Matter Emissions Research Articles

Optimization of Fleet Scrubber Installation and Utilization Considering Sulfur Emission Control Areas and Marine Fuel Switching

With the rising environmental consciousness, emission pollution has become one of the major concerns of the maritime industry, which is the artery of international trade. To handle the significant cost increase resulting from stringent emission regulations, ship operators have adopted multiple methods, including operational and technical methods. Scrubbers are a mature and effective technology that can reduce sulfur dioxide and particulate matter emissions by cleaning the exhaust gases before emitting them. However, the existing literature regarding the operation of scrubbers does not consider the prohibition of open scrubber usage in the vicinity of certain ports or the variable costs of using scrubbers. Therefore, this study explores the fleet scrubber installation and utilization problem, considering sulfur emission control areas, marine fuel switching, and open-scrubber-prohibited areas. A mixed-integer nonlinear model was developed to formulate and address the problem. Numerical experiments and sensitive analyses based on practical data were conducted to validate the originally proposed model and show the effectiveness of this technology under various scenarios. The results indicated that the operational cost was effectively reduced by using scrubbers, compared to not using them. Additionally, the disparity between total costs with and without scrubbers was significant, regardless of the sailing speed and proportion of the regulation areas. It was also proven that spreading the scrubber installation work over several years will relieve financial pressures due to scrubber investment and thus obtain a better installation plan.

Investigation of performance, combustion and exhaust emission characteristics of a compression ignition engine fuelled with diesel-kerosene-ethanol-hydrogen strategies

The current investigation acmes the ascendancy of ethanol on the performance, combustion and exhaust emissions of adulterated diesel fuelled compression ignition engine. Diesel adulteration by kerosene results in an adverse effect on performances and carbon emissions of the engine, but significantly reduces oxides of nitrogen. A small amount of ethanol incorporation into the adulterated diesel avowedly improves the performance, combustion and exhaust emissions of the engine. To this end, the engine is further modified for injecting hydrogen to reveal the competency of five different strategies along with 85% diesel, 5% kerosene and 10% ethanol blended fuel in volumetric proportion. The small amount of hydrogen enrichment aids in the improvement of brake thermal efficiency (up to 3.2%), brake specific energy consumption (up to 3.1%), in-cylinder pressure, heat release rate, brake specific hydrocarbon (up to 50.1%), brake specific carbon monoxide (up to 50.5%) and brake specific particulate matter (up to 44.8%) emissions.

Emission Characteristics of Particulate and Gaseous Pollutants from a Light-Duty Diesel Engine with SDPF.

Due to the inherent combustion characteristics of diesel engines, particulate matter (PM) and nitrogen oxides (NOx) are the main pollutants of diesel engines. NOx emissions under low load and low temperature are the focus of future regulation. Selective catalytic reduction coated on diesel particulate filter (SDPF) can reduce NOx and PM emissions of diesel engines at the same time, especially improving the emission characteristics of NOx under low load and low temperature. In this paper, a light-duty diesel engine with diesel oxidation catalyst (DOC) and SDPF was studied, and emission of particulate and gaseous pollutants of the engine before DOC, after DOC, and after SDPF was measured under 10 steady-state operating conditions. The effects of SDPF on particulate size distribution, the filtration efficiency of particulate, and the conversion efficiency of gaseous pollutants were analyzed. The results show that DOC + SDPF can trap PM with particle sizes between 10 and 23 nm by 1-2 orders of magnitude, and the conversion and filtration efficiency of DOC + SDPF for both gaseous pollutants and PM exceeds 90% under low-temperature and low-load conditions. The filtration efficiency of SDPF is 94.37% for PM and 90.36% for PN, and the conversion efficiency is 91.43% for NOx.

Synergistical reduction of PM and NO formation in preheating co-firing of coal and biomass

Preheating co-firing of coal and biomass was proposed for synergetic mitigation of pollutant source emissions. The effects of different operating parameters on particle matter (PM) and nitric oxide (NO) emissions were investigated, including excess air ratio (αp), temperature (Tp), residence time (tp) in the preheating zone and temperature (Tc) in the combusting zone. Coal and biomass particles were fed separately by two feeders, mixed uniformly in a mixing device and then inserted in a high-temperature drop-tube furnace. PM and NO emissions at the furnace outlet were measured by ELPI+ and the infrared gas analyzer. The results showed that as αp increased from 0 to 0.5, PM10 emission declined by 10.65% while NO emission went down first and then rose up with a turning point at αp = 0.3 of 247.93 mg/m3. When Tp increased from 1400 K to 1800 K, PM10 emission increased but NO emission decreased. The increase in the former was more than twice the decrease in the latter. More interestingly, the forming mechanism of ultrafine mode PM0.3 was dominated by “solid-vapor” process at low combusting temperature but transformed into “vapor-particle” process at high temperature. When Tc ascended from 1700 K to 1800K, the dominant “vapor-particle” process was inhibited, leading to a decrease of 13.5% in PM0.3 emission. PM0.3-2.5, PM2.5-10 and NO emissions were boosted by 64.99%, 36.40% and 78.20% respectively with Tc ascending from 1400 K to 1800 K. As tp rose from 0.1 to 0.5, the production of PM0.3 and NO decreased by 29.50% and 44.55% respectively, but that of PM0.3-2.5 and PM2.5-10 increased by 20.04% and 33.83% continuously. Under optimum parameters (Tp = 1300 K, αp = 0.3, Tc = 1400 K and tp = 0.5 s), PM10 and NO emissions could be reduced by 30.88% and 48.01%, respectively.

Effect of third-party components on emissions from a pod style electronic cigarette.

Electronic nicotine delivery systems (ENDS) have been associated with a dramatic increase in youth becoming addicted to nicotine following decades-long decline in cigarette smoking uptake. The United States Food and Drug Administration, Center for Tobacco Products (FDA/CTP) is responsible for regulating devices and consumable materials associated with ENDS. State and federal regulations regarding flavoring compounds in ENDS liquids (e-liquids) may be circumvented when vendors market refillable reservoirs side-by-side with noncompliant e-liquids. This study investigated the effect of third-party refillable versus manufacturer-supplied single-use reservoirs on total particulate matter (TPM) and nicotine emissions. The maximum TPM yield per puff was 5.6 times higher for the third-party (Blankz) reservoir (12.4 mg/puff) in comparison with the manufacturer's (JUUL) reservoir (2.2 mg/puff), whereas the maximum TPM concentration was over 7 times higher for third party (0.200 mg/ml) versus manufacturer (0.028 mg/ml) pod. The third-party pod was tested with nicotine concentrations ranging from 0% to 4%. The mass ratio of nicotine present in the aerosol (mg Nic/mg TPM) was found to be approximately the same as the mass ratio of the e-liquid (mg Nic/mg e-liquid) for both pods and all 3 nicotine laden e-liquids tested. Toxicant exposure may increase when consumers use third-party pods with ENDS devices. Refillable reservoirs are a significant barrier to regulatory restrictions on potentially toxic additives to e-liquids. It is recommended FDA/CTP require emissions characterization of third-party reservoirs used with each ENDS they are compatible with and should be required to demonstrate no increased potential toxicant exposure in comparison with manufacturer-provided reservoirs.

Variation of PM2.5 and PM10 in emissions and chemical compositions in different seasons from a manure-belt laying hen house

Particulate matter (PM) emissions from animal houses and the corresponding hazard have raised increasing attention during recent years. In this study, a large-scale manure-belt laying hen house located in Beijing, China was selected as the experimental site for the study of the emission rates (ER) and chemical compositions of PM2.5 and PM10 in 3 seasons, namely, summer, autumn, and winter, to investigate their possible influences on ambient air quality and human health. The results showed that the mean ER from the hen house in summer, autumn, and winter were 9.0 ± 1.7, 2.4 ± 0.7, and 1.9 ± 0.7 mg hen-1 d-1 for PM2.5 (P < 0.05), and 30.7 ± 1.1, 12.8 ± 1.5, and 10.9 ± 0.9 mg hen-1 d-1 for PM10 (P < 0.05), respectively. Moreover, large amounts of secondary inorganic aerosols (SIA) were observed inside the house in summer, accounting for 11.4 and 9.6% of indoor PM2.5 and PM10 mass, respectively, compared with the value of <1.4% in autumn and winter. Among the 31 detected elements in indoor PM, arsenic concentration exceeded the threshold set in legislation. Zn had a notably high concentration of 3,403 to 4,432 ng m-3 in indoor PM10, which was 28 to 71 times higher than that in ambient PM10. The findings suggest that the poultry-raising house emit PM2.5 and PM10 containing SIA and toxic heavy-metal elements such as As and Zn to the ambient with much more emissions in summer than in autumn and winter. Considering the increasing development of poultry-raising farming in China, the potential hazard derived from the exhaust of PM2.5 and PM10 should be focused on, especially during summer.

Formation and migration of soluble ions in condensable particulate matter in limestone-gypsum wet flue gas desulfurization system

In this work, the emission characteristics of condensable particulate matter (CPM) and soluble ions in the inorganic components after wet flue gas desulfurization (WFGD) were investigated by adjusting the operating parameters of the limestone-gypsum WFGD system. Using a combination of US Method 202 and US EPA Method 5 as the primary measurement method, the study is an experimental study and analysis of the properties of CPM emitted from a limestone-gypsum WFGD system. Based on the measurement results, the influence of some important WFGD operating parameters on CPM emissions was evaluated. The results showed that CPM accounts for 84% of total particulate matter (TPM) emissions in desulfurized flue gas. The composition of CPM is primarily inorganic, comprising 96% of the components, with only a small portion being organic at 4%. The CPM that condensed to a solid state was generally less than 1 μm in diameter and mostly came from WFGD process. The analysis of soluble ions showed that Ca2+ and SO42- were the main ionic components in CPM. By adjusting the desulfurization operating parameters (inlet flue gas temperature, desulfurization solution temperature, desulfurization solution concentration), the concentration of soluble ions can be reduced to different degrees, so as to achieve the purpose of reducing CPM emission. This demonstrated that the CPM emission problem of limestone-gypsum WFGD system could be relieved by operating parameter optimization.

Relationship between PM2.5 pollution and firms’ emissions in Shaanxi Province, China

The relationship between the high-frequency time series of PM2.5 in the atmosphere and the air pollutants emitted by industrial firms is not yet fully understood. This study aimed to identify independent PM2.5 clustering regions in Shaanxi Province and to evaluate the spatio-temporal correlations of PM2.5 concentrations and pollutant emissions from industrial firms in these regions. To accomplish this, daily data on PM2.5 concentrations and air pollutants emitted by industrial firms were analyzed using the K-means spatial clustering method and cross-wavelet transformation. The results show that: 1) PM2.5 concentrations in Shaanxi Province can be divided into three independent clustering regions. 2) The lagged impact of industrial emissions on PM2.5 concentrations were about 1/4-1/2 period. 3) PM2.5 was mainly influenced by particulate matter (PM) emissions from industrial plants during the period of 16–32 days, while nitrogen oxides (NOx) significantly affected PM2.5 concentrations during the period of 32–64 days. 4) Emissions of PM, NOx, and sulfur dioxide (SO2) more significantly affect PM2.5 concentrations in northern and central Shaanxi, and pollutants emitted by firms in the thermal power generation, utility, and steel industries had more significant effects on PM2.5 concentrations than those emitted by the cement manufacturing and electric power industries. During the COVID-19 shutdown, the emissions of firms cannot significantly affect PM2.5 concentrations. These findings suggest that emission reduction initiatives should consider industrial, regional, and periodic differences to reduce PM2.5 pollution during winter.

Cattle Grazing Moderates Greenhouse Gas and Particulate Matter Emissions from California Grassland Wildfires

Between 2010 and 2020, an average of 36,037 hectares of grassland burned in wildfires in California each year, emitting greenhouse gasses (GHGs) and particulate matter (PM). These emissions impact climate and human health. Cattle grazing removes herbaceous fuel through the consumption of forage; however, ruminant digestion also emits GHGs. The purpose of this study was to examine the GHG and PM impact of livestock grazing in grasslands that go on to burn. We used Monte Carlo simulation to determine whether forage consumption by livestock led to reductions in grassland wildfire emissions and whether these reductions outweighed the emissions from the digestion of that forage. We estimate that between 2010 and 2020, an average of 11,590 metric tons (MT) of herbaceous fuel were removed by cattle annually from grasslands in California that went on to burn. This resulted in annual wildfire emission reductions ranging between 0.001 and 0.025 million metric tons (MMT) of CO2 equivalents (CO2e) and between 11 and 314 MT of PM2.5; a small fraction of total GHG and PM emissions from wildfires in California. We also evaluated the change in emissions if burned grasslands in California’s Central and North Coast regions—where removing grazing can lead to the encroachment of shrubs into grasslands—were instead shrublands. If the grasslands that burned in these regions in 2020 had instead been shrublands, we estimate that as much as 0.90 MMT more CO2e and 8448 MT more PM2.5 would have been emitted by wildfires, highlighting the long-term implications of livestock grazing.

Thermal evaluation of plant biomass from the phytostabilisation of soils contaminated by potentially toxic elements

The combination of phytoremediation of soils contaminated by potentially toxic elements with energy production by combustion of the generated biomass can be a sustainable land management option, combining the production of renewable bioenergy with soil restoration while minimising energy consumption and CO2 emission. In this work, plant biomass from phytoremediation of soils contaminated by potentially toxic elements was studied as solid biofuel for combustion by thermal analysis and biomass composition. Six plant species were grown in two soils with differing degrees of contamination: Brassica juncea, Cynara cardunculus, Atriplex halimus, Nicotiana glauca, Dittrichia viscosa, Retama sphaerocarpa and Salvia rosmarinus. The composition of the plant biomass was characterised chemically and thermogravimetric analyses were performed for the mass loss (TG), derivative curves of mass loss (DTG) and temperature difference (DTA) signal. The cellulose concentration correlated with the parameters of the thermal analysis in the low temperature range (150–350 °C), while lignin correlated with the thermal parameters of the second peak in the high temperature range. Salvia rosmarinus and R. sphaerocarpa showed the best combustion characteristics according to the thermal profile and mineral residue results. The accumulation of potentially toxic elements in B. juncea grown in heavily contaminated soil led to a higher amount of residue at 750 °C, with a global activation energy lower than the one obtained when this species was grown in a soil with lower contamination. Therefore, the most beneficial combination of soil phytoremediation and energy production (combustion) that can be suggested would depend on the level of soil contamination: in heavily contaminated soil, phytostabilisation using R. sphaerocarpa and S. rosmarinus; in slightly contaminated soil, B. juncea due to its high energy of activation, although the concentrations of potentially toxic elements in the residue must be controlled, as well as possible particulate matter emissions during combustion.

Incense smoke (IS) inhalation exposure system: Physicochemical characterization, IS particle deposition and clearance in human airway using MPPD model

Incense smoke (IS) is source of indoor air pollution and key risk for diverse human diseases. Less information is available regarding controlled IS rodent inhalation exposure system and IS particulate matter (PM) deposition in human airways. Study aimed to demonstrate stable ISPM physicochemical parameters of 10 incense products inside the customized whole body inhalation exposure chamber (without animal) connected to smoke generation unit via aerosol mixing device. IS analyzed for size segregated PM emission, ISPM in vitro aerodynamics (MMAD and GSD determination), fine and ultrafine particle's SEM, SEM-EDX and PAH analysis. Using real life exposure scenario by utilizing MMAD, GSD and PM concentration after Tier 1 exposure assessment as key input parameters, ISPM dosimetry in infant (3 months) and adult (21 years male and female) human airways was calculated using multiple-path particle dosimetry (MPPD 3.04) modeling. Mass median aerodynamic diameter (MMAD) and geometric standard deviation (GSD) ranged between 0.55 and 2.10 μm and 1.22 to 1.77 (polydisperse) respectively. PM1.0 and PM0.1 showed multiple morphology and presence of heavy and trace elements. PAH like acenaphthylene, anthracene, fluorene, naphthalene and phenanthrene were detected (0.84–143.17 μg/g). MPPD results showed higher ISPM deposition in pulmonary region and lowest in trachea bronchial region. ISPM deposition in tissue was higher in lower, peripheral lung as compared to upper and central lung tissue. Whole body inhalation exposure system showed stable IS atmosphere (physicochemical parameters) indicating the device suitability in future inhalation studies. MPPD ISPM deposition fraction and clearance data showed deep lung penetrating and retention behavior with higher risk in infant followed by female and then male. These modeled particle deposition and clearance data may be useful in risk assessment analysis of IS.

TEs enrichment characteristic in different size particulate from coal-fired flue gas: Part 1. Enrichment and leachability

The trace elements (TEs) and particulate matter (PM) emissions from coal-fired power plants have received much concern in recent years due to their harm to human health and the environment, however, the TEs enrichment characteristic in PM and their migration and transformation mechanisms with PM are not clear yet, especially in fine particles. In this work, the enrichment contents of seven TEs Cd, Pb, Mo, As, Ni, Mn, Cr in coal combustion byproducts collected from circulating fluidized bed (CFB) and pulverized coal (PC) boiler were studied to investigate the influence of boiler type on TEs enrichment behavior. The aerodynamic cutting method was used to separate the fine particles PM10 and PM2.5 from bulk fly ash to study the impact of particle size on TEs enrichment behavior. In addition, the modified BCR sequent extraction method was applied to study TEs occurrence forms in different size particles to evaluate their environment contamination risk. The results show that except low volatility Mn, all the TEs are mainly enriched in fly ash rather than bottom slag and gypsum. The coal combustion in PC boiler is more complete so bottom slag in PC boiler commonly has less TEs enrichment content than that in CFB boiler. The volatile TEs including Cr, Ni, As, Cd, Pb are most enriched in PM2.5, while the enrichment contents based on fly ash volume fraction of seven TEs are most in PM50 (for CFB boiler) and PM10 (for PC boiler), since PC boiler has more PM10 volume fraction. Even though the TEs occurrence forms in different size particles are various due to the complexity of TEs combination mechanism with fly ash, the soluble F1 fraction overall exhibits size-dependence and is highest in PM2.5. RAC result indicates that As, Cd, Mn, Ni, Cr have medium environment risks, especially when they occur in PM2.5.

Hydrocarbon and particulate matter evolution in the exhaust manifold of a spark-ignited engine under cold-start operation

Cold-start, as defined by the time between first engine crank and three-way catalyst light-off, is responsible for a large percentage of NOx, unburned hydrocarbon, and particulate matter (PM) emissions in light-duty engines. Minimizing emissions during cold-start is a trade-off between achieving faster three-way catalyst light-off, and engine out emissions during that period. In this study, various exhaust gas and PM species were measured at three locations in the exhaust manifold using advanced hydrocarbon and PM speciation methods in addition to standard exhaust-gas-analyzers to characterize how or if these species evolve downstream of the exhaust port during cold-start operation. A gasoline direct injected spark ignited (DISI) single cylinder engine was run at 2-bar net indicated mean effective pressure (NIMEP) at spark timings ranging from normal-SI operation relevant early spark timing of -10 degrees after top dead center firing (dATDCf) to more cold-start-relevant retarded spark timing of 25dATDCf. At the retarded spark timings, the exhaust manifold gas temperature increased downstream of the exhaust port indicating the presence of oxidation reactions that counteract heat transfer losses; a trend also supported by oxidation of total hydrocarbons (THC), CO, and H2 observed downstream of the exhaust port. Additionally, increase in NOx emissions downstream of the exhaust port indicated presence of high temperature required to drive NOx chemistry. Aromatics were the largest exhaust hydrocarbon species group detected at all spark timings, while the paraffins were under-represented from their fuel composition fraction. Organic carbon accounted for more than 95% of the PM mass at exhaust port for all spark timings. At retarded spark timings, the PM mass reduced downstream of the exhaust port primarily driven by organic carbon oxidation. Particle number and size measurements at retarded spark timings indicated a reduction in particle count downstream of the exhaust port with an accompanying increase in particle size possibly due to agglomeration.

Combustion Parametric Investigations of Methanol-Based RCCI Internal Combustion Engine and Comparison with the Conventional Dual Fuel Mode

Reactivity-controlled compression ignition (RCCI) is an advanced combustion mode. Its uses two fuels with different physical and chemical properties to form a combustible mixture with active stratification. RCCI can flexibly control the combustion process by changing the concentration and activity of the combustible mixture. It can also reduce the emission of NOx and particulate matter in the engine without significantly reducing the thermal efficiency. Among various fuel combinations, methanol as an oxygen-containing fuel, has a high latent heat of vaporization, which is conducive to reducing combustion temperature and achieving low-temperature combustion. This experimental study explores the potential of Methanol-Diesel Reactivity Controlled Compression Ignition (RCCI) in achieving low emissions and high thermal efficiency and compares this with the conventional dual fuel mode. Low-temperature combustions such as Reactivity Controlled Compression Ignition (RCCI) have been shown to be a promising way to reduce pollutants at the exhaust, i.e. NOx and soot emissions. and increase the thermal efficiency of future engines. The methanol to diesel energy share (MDES) could be enhanced to 56% in the RCCI mode with proper setting of the injection parameters from 45% in the dual fuel mode. A higher quantity in the second diesel pulse that occurred close to TDC led to higher thermal efficiency and good combustion stability. Engines working in a dual-fuel mode need special conditions to ignite an air-fuel mixture without a spark plug in a good moment with high combustion efficiency.

Experimental Study of Fuel Combustion and Emission Characteristics of Marine Diesel Engines Using Advanced Fuels

Abstract In order to explore the potential application of oxygenated fuels, polyoxymethylene dimethyl ethers (PODE), as an alternative fuel for marine diesel engines, the fuel combustion performance and gas emission characteristics of pure diesel oil, diesel-blended PODE, and pure PODE were tested on a marine diesel engine under different running conditions. The experimental results indicate that oxygen consumption can be reduced by diesel-blended PODE and pure PODE. The in-cylinder pressure and exothermic curve were consistent with the trend of diesel oil. Also, the ignition delay of diesel-blended PODE and pure PODE decreased, and the diffusion rate was accelerated, which helped to improve the combustion performance of diesel engines. Diesel blended PODE and pure PODE reduced the particulate matter (PM) emissions by up to 56.9% and 86.8%, respectively, and CO emissions by up to 51.1% and 56.3%, respectively. NOx emissions were gradually decreased with engine load. CO2 emissions were slightly increased, and the effective fuel consumption was increased up to 48% and 132%, respectively. It was shown that PODE could provide comparable power in a marine diesel engine and improve the fuel combustion and gas emission of the engine as a clean alternative fuel for marine diesel engines.

Evaluating Non-exhaust Particulate Matter Emissions in Feasibility Studies of Transportation Investment Projects

Evaluating Non-exhaust Particulate Matter Emissions in Feasibility Studies of Transportation Investment Projects

Reductions of Particulate Matters Emission by Soil Surface Management of Potato-Cultivated Fields in Saemangeum Reclaimed Land

Reductions of Particulate Matters Emission by Soil Surface Management of Potato-Cultivated Fields in Saemangeum Reclaimed Land

Ultra-low soot/ particulate emissions from a dimethyl ether-fueled agricultural tractor engine

This study eveluates using dimethyl ether (DME) fuelled engine for marching towards zero soot and particulate matter (PM) emissions in the agricultural sector. Comparative emissions and particulate characteristics were analysed for a customised DME-fuelled engine and an unmodified baseline diesel engine. The experimental investigations were performed on a multi-cylinder tractor engine using a dedicated DME fuel injection equipment (FIE) and an unmodified diesel FIE. Regulated emissions, namely carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx), smoke opacity, and particulates were measured at three engine speeds (1200, 1600 and 2000 rpm) and five loads (1.29, 2.59, 3.88, 5.18, and 6.47 bar BMEP). The static fuel injection timing for both test fuels was maintained constant; however, the actual injection timing could be slightly different for both test fuels because of their different physicochemical properties. DME-fuelled engine exhibited relatively higher HC and CO emissions than diesel at low loads; however, both test fuels exhibited nearly identical emissions at higher loads. NOx emissions were lower for DME-fuelled engine than baseline diesel, and its smoke opacity was also negligible at all engine loads and speeds. The particulate number concentration for DME-fuelled engines was much lower than baseline diesel at all test conditions, except 1.29 bar BMEP. Particulate emissions from DME-fuelled engine were mainly in the form of nanoparticles and nucleation mode particles, with negligible numbers of accumulation mode particles. This experimental study demonstrated that DME-fuelling of the tractor engine reduced emissions and it can be used as a sustainable and greener fuel to develop cleaner engines for agriculture/ transport sectors.

Development of a Spatial Tier 2 Emission Inventory for Agricultural Tractors by Combining Two Large-Scale Datasets

Agricultural tractor emissions have a notable influence on total emissions and climate change. This is especially important when developing an agricultural machinery emission inventory since tractors are the most widely used agricultural machinery. However, as with other agricultural machinery, there is a significant lack of data concerning tractors. This study combined two large-scale datasets to develop a Tier 2 tractor emission inventory for the Republic of Croatia. The first dataset, which was collected via a large-scale survey with 8895 respondents, includes data on fuel consumption by machine and engine type. The second dataset, which is official data of the Ministry of the Interior, includes data on machinery age. Since there is no direct link between datasets, data on fuel consumption were calculated for each of 21 Croatian counties and were then linked to the corresponding municipalities’ tractor age and power rating of the vehicle fleet. The result was used to calculate tractor emissions by with a Tier 2 approach using the method listed in the 2019 EMEP/EEA emissions guidebook. The calculations were made for five exhaust emission components: carbon dioxide (CO2), carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOX) and particulate matter (PM). The continental counties had the highest emissions for all emission types, especially the Osječko-baranjska and Vukovarsko-srijemska counties. The Tier 2 emission inventory was compared to data calculated using the Tier 1 method on a county level. There were notable differences between the inventories for HC and PM emissions, which is mainly due to Tier 2 approach having different emission factors depending on vehicle age. The end result was compared to the already existing Tier 1 emission inventory on a county level.

Key factors for abating particulate matter in a highly industrialized area in N Spain: Fugitive emissions and secondary aerosol precursors

In highly industrialized areas, abating particulate matter (PM) is complex owing to the variety of emission sources with different chemical profiles that may mix in the atmosphere. Gijón—an industrial city in northern Spain—was selected as a case study to better understand the key emission sources and improve air quality in highly industrialized areas. Accordingly, the trends of various air quality indicators (PM10, PM2.5, SO2, NO2, and O3) during the past decade (2010–2019) were analyzed. Additionally, the inorganic and organic PM10 compositions were analyzed for source apportionment studies and to assess the impact of COVID-19 restrictions on PM10 levels.The results revealed that over the past decade, PM10 concentrations decreased, whereas PM2.5 concentrations dominated by secondary inorganic aerosols (SIA) remained relatively constant. Notably, during the COVID-19 lockdown, the PM10 concentration increased by 9.1%, primarily owing to an increase in regional SIA (>65%) due to specific meteorological conditions that favor the formation of secondary PM from gaseous precursors. Overall, eight key PM10 sources were identified: “industrial fugitive PM resuspension” (FPM, 28% of mean PM10 concentration), “aged sea spray” (SSp, 16%), “secondary nitrate” (SN, 15%), “local diffuse source” (LPM, 12%), “solid fuel combustion” (SFC, 7.8%), “biomass burning” (BB, 7.4%), “secondary sulphate” (SSu, 6.0%), and “sinter” (SIN, 4.5%). The PM10 concentration in Gijón is significantly influenced by the integrated steel industry (FPM, SFC, and SIN; 41% of PM10) and fugitive primary PM emissions were the main source (FPM and LPM; 40%). To reduce PM10 and PM2.5 concentrations, industrial fugitive emissions, which are currently poorly regulated, and SIA precursors must be abated.This study provides a methodological approach that combines trend analysis, chemical speciation, and source apportionment for assessing pollution abatement strategies in industrialized areas with a complex mix of emission sources.