Living in counties where manufacturers release environmental toxins, such as those tracked by the Environmental Protection Agency's (EPA) toxic release inventory (TRI), may elevate infants' health risks. Because infant mortality (IM) is a strong indicator of a population's health status, it is an important topic in public health research. The purpose of this research was to examine the potential relationships between IM, community size, and factors related to mothers' SES in counties where more than 25,000 pounds of annual toxic air releases occur. The dependent variable was IM per 1,000 live births in a given community for each of the 3 years included in this analysis (1987, 1995, and 2004). The independent variables included county size and factors related to mother's SES (education, age, ethnicity, and marital status). The theoretical framework consisted of Mosley and Chen's framework for exploring child survival. Archival, publicly available data were pulled from (a) the EPAs TRI data, and (b) linked birth and infant death files from the National Center for Health Statistics. The researcher followed a quantitative, retrospective cross-sectional design and conducted 3 linear regression models to test the research questions. Results indicated that an increase in community size was significantly associated with an increase in IM. Regarding the relationships between IM and the 4 different maternal characteristics (education, age, ethnicity, and marital status) included in the analysis, findings were mixed for the 3 years examined. Despite these unexpected findings, the overall results from this investigation, when considered alongside findings from previous research on IM, indicate that policy changes and interventions are needed to reduce socioeconomic disparities in IM, and to save the lives of more infants.

Excessive PM2.5 emissions in China threaten peoples’ health and cause massive economic burdens to society. Under pressure from the public, and the international community, China published PM2.5 standards for the first time in March 2012. Following the introduction of standards, several pilot cities began to build PM2.5 monitoring networks. This paper is designed to explore whether PM2.5 monitoring can be effectively undertaken and implemented in China and whether monitoring results can offer a technical basis to facilitate a significant reduction in actual PM2.5 emissions and protect public health. PM2.5 monitoring is essential in helping the government and public monitor pollution levels and supervise local compliance with PM2.5 standards. Key aspects to facilitate an effective monitoring process are discussed in the analysis. In addition, a case study – Lanzhou’s PM2.5 monitoring network – is provided to analyze and improve current PM2.5 monitoring practices at local levels, as well as suggest credible technical support to local authorities so as to cut PM2.5 emissions levels. Based on detailed analysis, the results suggest that PM2.5 monitoring can be successfully implemented in China by following several key principles – designing a representative PM2.5 monitoring network, applying QA/QC to ensure data quality, interpreting the data scientifically to understand real pollution levels, etc. In addition, this paper recommends three measures critical to realizing PM2.5 reduction goals: (1) emissions source control, (2) public participation to add input to the decision-making process and supervise local compliance with PM2.5 standards, and (3) non-governmental organization/international cooperation to improve local government and environmental agencies’ capacity with regards to environmental protection. Lessons derived from the case study can help improve PM2.5 monitoring performance not just in Lanzhou, but in cities that share similar monitoring issues across China. Scientific monitoring, together with the application of the above three measures, can more effectively curb PM2.5 emissions, improve air quality, and mitigate negative health effects associated with air pollution. / acase@tulane.edu

The overall goals of this dissertation are: 1) to better quantify the spatial heterogeneity of coarse particulate matter (PM10-2.5) and its chemical composition; and 2) to evaluate the performance (accuracy and precision) of passive samplers analyzed by computer-controlled scanning electron microscopy with energy-dispersive X-ray spectroscopy (CCSEM-EDS) for PM10-2.5. For these goals, field studies were conducted over multiple seasons in Cleveland, OH and were the source of data for this dissertation. To achieve the first goal, we characterized spatial variability in the mass and composition of PM10-2.5 in Cleveland, OH with the aid of inexpensive passive samplers. Passive samplers were deployed at 25 optimized sites for three week-long intervals in summer 2008 to characterize spatial variability in components of PM10-2.5. The size and composition of individual particles were determined using CCSEM-EDS. For each sample, this information was used to estimate PM10-2.5 mass and aerosol composition by particle class. The highest PM10-2.5 means were observed at three central industrial urban sites (35.4 Μg m-3, 43.4 Μg m-3, and 47.6 Μg m-3), whereas lower means were observed to the west and east of this area with the lowest means observed at outskirt suburban background sites (12.9 Μg m-3 and 14.7 Μg m-3). Concentration maps for PM10-2.5 and some compositional components of PM10-2.5 (Fe oxide and Ca rich) show an elongated shape of high values stretching from Lake Erie south through the central industrial area, whereas those for other compositional components (e.g., Si/Al rich) are considerably less heterogeneous. The findings from the spatial variability of coarse particles by compositional class analysis, presented in Chapter II of this dissertation, show that the concentrations of some particle classes were substantially more spatially heterogeneous than others. The data suggest that industrial sources located in The Flats district in particular may contribute to the observed concentration variability and heterogeneity. Lastly, percent relative spatial heterogeneity (SH%) is more consistent with spatial heterogeneity as visualized in the concentration surface maps compared to the coefficient of divergence (COD). The second goal was achieved by assessing the performance of passive samplers analyzed by CCSEM-EDS to measure PM10-2.5 (Chapter III) and investigating potential sources of variability in the measurement of PM10-2.5 with passive samplers analyzed by CCSEM-EDS (Chapter IV). Data for these analyses were obtained in studies conducted in summer 2009 and winter 2010. The precision of PM10-2.5 measured with the passive samplers was highly variable and ranged from a low coefficient of variation (CV) of 2.1% to a high CV of 90.8%. Eighty percent of the CVs were less than 40%. This assessment showed the CV for passive samplers was greater than that recommended by the United States Environmental Protection Agency (EPA) guidelines for the Federal Reference Method (FRM). Several CV values were high, exceeding 40% indicating substantially dissimilar results between co-located passive samplers. The overall CV for the passive samplers was 41.2% in 2009 and 33.8% in 2010. The precision when high CVs > 40% (n = 5 of 25) were excluded from the analysis was 24.1% in 2009 and 18.2% for 2010. Despite issues with precision, PM10-2.5 measured with passive samplers agreed well with that measured with FRM samplers with accuracy approaching EPA Federal Equivalent Method (FEM) criteria. The intercept was 1.21 and not statistically significant (p = 3.88). The passive to FRM sampler comparison (1:1) line fell within the 95% confidence interval (CI) for the best-fit linear regression and was statistically significant (p < 0.05). However, several data points had large standard deviations resulting in high variability between co-located passive samplers (n = 3), which extend outside of the 95% CI's. The passive sampler limit of detection (LOD) for the CCSEM method was 2.8 Μg m-3. This study also showed certain samples had higher CVs and that further investigation was needed to better understand the sources of variability in the measurement of PM10-2.5 with passive samplers. Sources of variability observed in the measurement of PM10-2.5 with passive samplers analyzed by CCSEM were explored in Chapter IV of this dissertation. This research suggests mass concentrations greater than 20 Μg m-3 for week long samples are needed on the passive sampler substrate to obtain overall CVs by mass less than 15%. It also suggests that greater than 55 particle counts within a compositional class are needed to reduce analytical CVs to less than 15%. Another finding from this study was increasing the concentration from 6.2 to 10.6 Μg m-3 increases the CCSEM analytical precision by mass 38% and by number 75% for random orientation. Also certain compositional classes appeared problematical for precision of passive sampler measurements. For example, the presence of salt plus moisture introduces challenges for CCSEM analysis through the wetting of salt crystalline particles which dissolve creating a displaced dry deposition pattern of particles upon subsequent evaporation. This process can falsely elevate or reduce the particle count and alter its distribution on the sampling media.

Traditional aerosol samplers are limited in their abilities to collect large quantities of particulate matter due to their low flow rates, high pressure drops, and are noise intrusiveness. The goal of this study was to develop an alternate aerosol sampler using electrostatic precipitation technology that was safe and not noise intrusive to be deployed in homes. The O-Ion B-1000 was selected as the most suitable electrostatic precipitator (ESP) for achieving the goal of this study because of its affordability, the design of its collection electrode and its high flow rate. The collection efficiency of the ESP was assessed for three aerosols; Arizona Road Dust (ARD), NaCl and diesel fumes. ARD was found to have the highest average collection efficiency (65%) followed by NaCl (43%) and lastly diesel fumes (41%). A method for recovering the particulate matter deposited on the collection electrode was developed. The dust collected on the electrode was recovered onto polyvinyl chloride (PVC) filters moistened with deionized water. Additionally, the recovery of the three test aerosols, ARD, NaCl, and diesel fumes, from the collection electrode was assessed. A gravimetric analysis was done to determine the amount of dust recovered. The collection efficiency was used to calculate the amount of mass expected on the filter for a particular aerosol. NaCl had the highest recovery at 95% recovery, followed by ARD (73%) and lastly diesel fumes (50%). Two identical ESPs were also deployed in an office and in a bedroom, 104.47 mg and 9.64 mg of particulate matter (PM) was recovered respectively. The noise and ozone level produced by the ESP was evaluated to determine the ESP’s viability as a household aerosol sampler. The ESP’s high setting had a noise level of 45.8 dB and ozone generation rate of 0.036 mg/min. The results of the calculation showed that in an averaged size unventilated room (6.10 m × 6.10 m × 2.44 m), it would take 6 hours and 53 minutes for the ozone levels to reach the recommended maximum exposure limits per National Ambient Air Quality Standards (NAAQS). Additionally, a ventilation of 230 L/min is needed in order to prevent the ozone levels generated by the ESP from exceeding maximum exposure limits per NAAQS. Overall, the O-Ion B-1000 met the criteria of collecting 1 mg of PM in a 24 hour sampling for ARD and NaCl. Diesel fumes however, required 30 hours to collect 1 mg of PM. The noise levels generated by the ESP set on high was one dB above the Environmental Protection Agency (EPA) standards for indoor noise limit. However, the noise is proportional to inverse distance squared; the ESP should not pose a problem during household deployment. Ozone generated by the ESP was also found to be below 0.07 ppm as set by the EPA with an average ventilation of 230 L/min. The average ventilation of a household is 1500 L/min, thus the ozone generated by the ESP would not surpass 0.07 ppm. However, the ESP should not be deployed in unventilated rooms for a period of more than 6 hours and 53 minutes.

Chapter II describes results from 197 rural households that were sampled over five continuous days for indoor and outdoor PM10, PM2.5, and endotoxin. Geometric mean indoor concentrations of PM10 and PM2.5 (21.2 πg m-3, 12.2 πg m-3) were larger than outdoor concentrations (19.6 πg m-3, 8.2 πg m-3; p =0.072, p<0.001). While geometric mean endotoxin levels were almost six times larger in outdoor air compared to indoor (1.47 EU m-3, 0.23 EU m-3; p <0.001). Airborne PM10 and endotoxin concentrations in a rural county were elevated compared to those previously reported in certain urban areas. Furthermore, during the harvest season, concentrations of endotoxin in ambient air approached levels that have been shown to cause decreased respiratory function in occupational workers. Chapter III evaluated the effectiveness of using Radiello passive monitors to measure hydrogen sulfide (H2S) in close proximity (<40 m) to a medium sized CAFO. A total of eight passive H2S monitors were deployed 7-14 days around a swine confinement for seven months. Additionally, a separate laboratory study was carried out to determine the monitor's H2S uptake rate. Concentrations of H2S measured near the confinement were varied and ranged from 0.6 to 95 ppb depending on the sampling period and proximity to the lagoon .The uptake rate provided by the supplier (0.096 ng ppb-1 min-1) was significantly larger (p=0.002) than the rate determined experimentally (0.062 ng ppb-1 min-1). In Chapter IV we evaluated the association between residential proximity to swine operations and childhood asthma. A metric was created to determine children's relative environmental exposure to swine CAFOs which incorporated facility size and distance and direction of the CAFO to the home. When controlling for six significant asthma risk factors, children with a larger relative environmental exposure to CAFOs had a significantly increased risk of physician-diagnosed asthma (OR=1.20, p=0.009). In stratified analysis that adjusted for a respiratory infection before the age of two years, the association between relative exposure and childhood asthma was significantly increased in children with a respiratory infection (OR=1.45, p=0.001) but not in children free from respiratory infection (OR=1.12, p=0.355).

Karenia brevis is a toxic marine dinoflagellate species that blooms almost every year in the Gulf of Mexico. These blooms have had devastating effects on local economies, as well as on the fauna of the area. The ECOHAB:Florida project was founded to study the population dynamics and trophic impacts of K. brevis. The project included a series of monthly hydrographic offshore research cruises, as well as monthly surveys of a transect along the 10-meter isobath of the West Florida Shelf. This study focused on data from the alongshore transect over a three-year period (1999-2001). Physical parameters (temperature, salinity, and density) and chemical parameters (particulate carbon, nitrogen, and phosphorus; dissolved inorganic nitrogen and phosphorus) of the West Florida Shelf were analyzed. The amount of chlorophll a and the location and amount of K. brevis cells present were also examined. Clear spatial, seasonal, and interannual patterns in the hydrographic parameters, particulate matter (C, N, P), dissolved inorganic nutrient (nitrite, nitrate, and phosphate), and chlorophyll a concentrations were found. At various times throughout the study, the location of K. brevis blooms was influenced by all of these factors except for the amount of dissolved inorganic nutrients. There were differences in particulate matter ratios present in bloom and non-bloom periods. No clear-cut differences in dissolved inorganic nutrients between bloom and non-bloom periods were found. Finally, relationships between the biological indicators of blooms (i.e., chlorophyll a) and the aforementioned physical and chemical parameters were found.

The EPA press release dated February 23, 2004 states that the three Buckeye Egg Farm facilities had the potential to emit more than a combined total of 1850 tons per year of particulate matter (PM). This number was based on flowrate calculations that were three times higher than those measured as well as a failure to include particle size distributions in the emissions calculations. The annual PM emission for each facility was approximately 35 tons per year. The EPA was unjustified in requiring Buckeye Egg Farm to obtain Title V and PSD permits as the facilities could not have met the thresholds for these permits. Engineers need to be concerned with correctly measuring and calculating emission rates in order to enforce the current regulations. Consistency among regulators and regulations includes using the correct emission factors for regulatory permitting purposes. EPA has adopted AERMOD as the preferred dispersion model for regulatory use on the premise that it more accurately models the dispersion of pollutants near the surface of the Earth than ISCST3; therefore, it is inappropriate to use the same emission factor in both ISCST3 and AERMOD in an effort to equitably regulate PM sources. For cattle feedlots in Texas, the ISCST3 emission factor is 7 kg/1000 hd-day (16 lb/1000 hd-day) while the AERMOD emission factor is 5 kg/1000 hd-day (11 lb/1000 he-day). The EPA is considering implementing a crustal exclusion for the PM emitted by agricultural sources. Over the next five years, it will be critical to determine a definition of crustal particulate matter that researchers and regulators can agree upon. It will also be necessary to develop a standard procedure to determine the crustal mass fraction of particulate matter downwind from a source to use in the regulatory process. It is important to develop a procedure to determine the particulate matter mass fraction of crustal downwind from a source before the crustal exclusion can be implemented to ensure that the exclusion is being used correctly and consistently among all regulators. According to my findings, the mass fraction of crustal from cattle feedlot PM emissions in the Texas High Plains region is 52%.

Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Models successfully reproduce the concentrations of gas phase and PM phase species. Vehicles, natural gas, industries, and coal combustion are important O3 sources. Upwind sources have non-negligible influences (20-50%) on daytime O3, indicating that regional NOx emission controls are necessary to reduce O3 in Southeast Texas. EC is mainly from diesel engines while majority of primary OC is from internal combustion engines and industrial sources. Open burning, road dust, internal combustion engines and industries are the major sources of primary PM2.5. Wildfire dominates primary PM near fire locations. Over 80% of sulfate is produced in upwind areas and coal combustion contributes most. Ammonium ion is mainly from agriculture sources. The SOA peak values can be better predicted when the emissions are adjusted by a factor of 2. 20% of the total SOA is due to anthropogenic sources. Solvent and gasoline engines are the major sources. Oligomers from biogenic SOA account for 30-58% of the total SOA, indicating that long range transport is important. PAHs from anthropogenic sources can produce 4% of total anthropogenic SOA. Wild fire, vehicles, solvent and industries are the major sources. EC and OC emitted within 0-3 hours contribute approximately 70-90% in urban Houston and about 20-40% in rural areas. Significant diurnal variations in the relative contributions to EC are predicted. Fresh particles concentrations are high at morning and early evening. The concentrations of EC and OC that spend more than 9 hours in the air are low over land but almost accounts for 100% of the total EC and OC over the ocean.

The pollutant load in road runoff is related to traffic densities and road maintenance activities. Inurbanised areas treatment of road runoff is common and often considered necessary. The pollutantsare partitioned between the particulate and dissolved matter. However, the contaminantstend to have an affinity to the particulate material. Sedimentation, the predominant treatmentmethod for road runoff uses various types of ponds. Design tools used for stormwater treatmentsystems are based on extensive data from existing treatment systems. The variations in the empiricaldata make it difficult when attempting to evaluate precise conditions for pollutant removaland thereby minimising the land use for a treatment facility. This is a concern in highly urbanisedareas where land use often is restricted.In this work, field studies were conducted in three separate watersheds along the same motorwaywith an annual average daily traffic exceeding 120,000 vehicles. The aim was to assess treatmentconditions for the removal of contaminants from road runoff.The study of mass transport of total suspended solids used the EU Directive (1991/271/EEC)discharge requirement for urban wastewater treatment: 60 mg/l during winter and summer. Theresults showed that a capture of the total runoff volume was necessary during both seasons. Tenmetals (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), as dissolved and particulate bound, werestudied in the road runoff during a winter season and the following summer period. The dissolvedpart of Al, Cd, Co, Cr, Mn, and Ni was significantly higher in winter. The mass concentration(mg/kg) for all metals was significantly higher over the summer except for Al and Co, whichshowed a higher mass concentration during the winter. The total metal concentration showed agood correlation to total suspended solids (TSS) during winter with exception for Cd. Good correlationto TSS was also found for the summer period for Al, Cu, Fe, Mn, Ni, and Zn. A simplemodel could describe sedimentation by the initial concentration of TSS, albeit road salt (NaCl)had a significant impact on the sedimentation process during winter. Removal of dissolved metalswas studied by column experiments using water granulated blast furnace slag. The result showedgood removal for Cd, Cu, Ni, and Zn independent of NaCl concentrations. Sediment accumulation(mg sediment/mm precipitation) was relatively consistent for the studied summer seasons asopposed to winter. The sediment differed in metal mass concentrations (mg/kg) between theseasons. Concentrations of Cu and Zn were high in regard to the guidelines for sensitivity ofsediment dwelling organisms and Swedish guidelines for contaminated soils.The findings suggest that the entire runoff volume must be captured for treatment. The reductionof TSS concentration could be estimated for a specific surface load (m/h). This would alsoapply for majority of the studied metals that correlated well to the particulate material. Reactivefilter technology using water granulated blast furnace slag could be applied for treatment of runofffor the reduction of dissolved metals. However, long-term studies are necessary for its practicalimplementation. Furthermore; the work shows that on-line turbidity measurements could beused for expedient process control for treatment facilities in similar watersheds dominated byroads. The work could be used together with existing design methods and models to evaluate andoptimise road runoff treatment. / Föroreningsbelastningen i vägdagvatten är beroende av trafikbelastningen och vägunderhållet. Iurbaniserade områden är behandling av dagvatten vanlig och ofta bedömd nödvändig. Föroreningarnaär lösta och partikulära, men har vanligen en affinitet till det partikulära materialet. Denförhärskande behandlingsmetoden för dagvatten är sedimentering, vanligen i dammar. Designmodellernabygger på data från olika befintliga dagvattenanläggningar. Det varierande ursprungettill det empiriska underlaget medför svårighet att precist värdera designförutsättningarna och såledesminimera behandlingsanläggningens storlek. I förtätad stadsmiljö, där tillgång på mark ärbegränsad, kan detta vara ett problem.I detta arbete har fältförsök genomförts i tre avrinningsområden vilka domineras av en motorledmed en årlig dygnstrafik större än 120,000 fordon för att utvärdera behandlingsförutsättningar förvägdagvatten.Masstransporten av suspenderat material (SS) utvärderades utifrån EU Direktivet(1991/271/EEC) och gränsvärdet för avloppsvatten på 60 mg/l under vinter och sommar. Studienvisade att hela avrinningsvolymen bör behandlas oberoende av säsong. Fördelningen mellanpartikulärt och löst material studerades för tio metaller (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn)under vinter och sommar. Den lösta delen av Al, Cd, Co, Cr, Mn och Ni var signifikant högreunder vintern. Den partikulära koncentrationen (mg/kg) för samtliga metaller var högre undersommaren med undantag för Al och Co vilka förekom i högre halter under vintern. Totalhalten(μg/l) av metallerna korrelerade väl med SS under vintern med undantag för Cd. Likaledes uppvisaderesultaten en god korrelation mellan SS och Al, Cu, Fe, Mn, Ni och Zn under sommaren.Sedimenteringsegenskaperna kunde beskrivas med en enkel modell utifrån koncentration av SS,men förhöjda halter av vägsalt (NaCl) befanns påverka sedimenteringen under vintern. Reduktionav lösta metaller studerades i pilotförsök med vattenkyld granulerad masugnsslagg. God avskiljningerhölls för Cd, Cu, Ni och Zn oberoende av förhöjda halter av vägsalt. Ackumulering avsediment (mg sediment/mm nederbörd) befanns vara konstant under sommaren i motsats tillstuderade vinterperioder. Sedimentkoncentrationerna av Cu och Zn var förhöjda med avseendepå riktlinjer för känslighet hos sedimentlevande organismer samt för återanvändning av slam.Resultaten visar att hela avrinningsvolymen måste behandlas. Reduktion av SS samt huvuddelenav metallerna, vilka visade god korrelation till det partikulära materialet, kan skattas utifrån enspecifik ytbelastning (m/h). Reduktion av lösta metaller kan ske med granulerad masugnsslagg,dock bör långtidsstudier genomföras. Vidare visar studien på möjligheten att nyttja kontinuerligturbiditetsmätning för en effektiv och praktisk processkontroll i reningsanläggningar för liknandeavrinningsområden med hög trafikbelastning. Resultaten av arbetet kan användas för bedömningoch optimering av vägdagvattenbehandling tillsammans med existerande designmetoder och modeller. / QC 20100709

Particulate emissions from diesel engines have been a key issue for diesel engine developers in recent decades. Their work has succeeded in reducing the exhaust particles from the combustion of fuel, which has led to increasing interest in the contribution of particulates from lubrication oil. When discussing oil-related particulate emissions, hydrocarbon particles are customarily referred to. This thesis uses a broader definition, in which oil-related particulate emissions are modelled not only by the hydrocarbons, but also include the ash, carbons, and sulphate oil particulate emissions. The model developed in the project uses input data as oil consumption and oil ash content combined with tuning parameters, such as the oil ash transfer rate (ash emissions divided by oil consumption and oil ash content). Controlled engine tests have been performed to verify assumptions and fill knowledge gaps. The model can be applied to a variety of diesel engines, although the tuning factors might have to be reset. For example, introducing diesel particulate filters would dramatically reduce the oil ash emissions, since oil ash would accumulate in the filter. Oil consumption has played a central role in the present research. The modelling results indicate that special attention should be paid to oil consumption under running conditions with a low in-cylinder temperature, since the oil survival rate is high there. Under low-load and motoring conditions, hydrocarbons proved to be the main contributor to oil-related particulate emissions. At high engine load, oil ash emissions were the largest contributor to oil-related particulate emissions. / QC 20101103