The objectives of this study are (1) to separate fibrous grunerite (amosite) by its length using filtration and shaking techniques utilized in a previous study and (2) to create two distinct length groups (short and long) of the amosite with higher output in a cost-effective way. The shaking system included an electrodynamic exciter, a linear power amplifier, and an audio-frequency signal generator and was attached to a cowl sampler as a funnel loaded with a polycarbonate filter. A suspension of amosite was passed through the 10-μm pore size polycarbonate filter in the shaking system and was transferred to a filtration system through five different pore sizes of polycarbonate membrane filters in series from the top: 10-, 5-, 2-, 1-, and 0.2-μm pore sizes. Each polycarbonate filter was tightly clamped with two conductive 25-mm spacers with a 25-mm stainless steel support screen to prevent leakage. The amosite length and diameter were manually measured with images from a field emission scanning electron microscope (FESEM). A sequence of fields was selected at random locations, and an image of each field was acquired. The length and width of approximately 500 fibers for each sample were measured with ImageJ software. Two significantly different length groups (short and long) of amosite were collected (p <0.05). Approximately 95% of separated amosite (n = 499) using the filtration system were shorter than 5 μm (short fiber group), and approximately 80% of separated amosite (n = 503) using the shaking system were longer than 5 μm (long fiber group).

In October 2020, the CDC's Vaccinate with Confidence strategy specific to COVID-19 vaccines rollout was published. Adapted from an existing vaccine confidence framework for childhood immunization, the Vaccinate with Confidence strategy for COVID-19 aimed to improve vaccine confidence, demand, and uptake of COVID-19 vaccines in the US. The objectives for COVID-19 were to 1. build trust, 2. empower healthcare personnel, and 3. engage communities and individuals. This strategy was implemented through a dedicated unit, the Vaccine Confidence and Demand (VCD) team, which collected behavioral insights; developed and disseminated toolkits and best practices in collaboration with partners; and collaborated with health departments and community-based organizations to engage communities and individuals in behavioral interventions to strengthen vaccine demand and increase COVID-19 vaccine uptake. The VCD team collected and used social and behavioral data through establishing the Insights Unit, implementing rapid community assessments, and conducting national surveys. To strengthen capacity at state and local levels, the VCD utilized "Bootcamps," a rapid training of trainers on vaccine confidence and demand, "Confidence Consults", where local leaders could request tailored advice to address local vaccine confidence challenges from subject matter experts, and utilized surge staffing to embed "Vaccine Demand Strategists" in state and local public health agencies. In addition, collaborations with Prevention Research Centers, the Institute of Museum and Library Services, and the American Psychological Association furthered work in behavioral science, community engagement, and health equity. The VCD team operationalized CDC's COVID-19 Vaccine with Confidence strategy through behavioral insights, capacity building opportunities, and collaborations to improve COVID-19 vaccine confidence, demand, and uptake in the US. The inclusion of applied behavioral science approaches were a critical component of the COVID-19 vaccination program and provides lessons learned for how behavioral science can be integrated in future emergency responses.

The case study was conducted in an underground coal mine to characterize submicron aerosols at a continuous miner (CM) section, assess the concentrations of diesel aerosols at the longwall (LW) section, and assess the exposures of selected occupations to elemental carbon (EC) and total carbon (TC). The results show that aerosols at the CM sections were a mixture of aerosols freshly generated at the outby portion of the CM section and those generated in the main drifts that supply fresh air to the section. The relatively low ambient concentrations and personal exposures of selected occupations suggest that currently applied control strategies and technologies are relatively effective in curtailing exposures to diesel aerosols. Further reductions in EC and TC concentrations and personal exposures to those would be possible by more effective curtailment of emissions from high-emitting light duty (LD) vehicles. 2022, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted a study in an isolated zone of an underground mine to characterize aerosols generated by: (1) a diesel-powered personnel carrier vehicle operated over a simulated light-duty cycle and (2) the simulated repair of existing equipment using manual metal arc welding (MMAW). Both the diesel-powered vehicle and MMAW process contributed to concentrations of nano and ultrafine aerosols in the mine air. The welding process also contributed to aerosols with electrical mobility and aerodynamic mobility count median diameters of approximately 140 and 480 nm, respectively. The welding particles collected on the filters contained carbon, iron, manganese, calcium, and aluminum.

NIOSH researchers designed a high-sensitivity (HS) cassette to improve the limit of detection of the National Institute for Occupational Safety and Health's (NIOSH) method 5040 and the Airtec near real-time diesel particulate matter (DPM) monitor. This was achieved by reducing the size of the diesel particulate matter deposition spot from 8.0 cm(2) (NIOSH method 5040 mining samples) and 7.6 cm(2) (Airtec samples) to 0.5 cm(2). When compared with the standard cassette, the new high-sensitivity cassette improves the limit of detection of NIOSH method 5040 by approximately five times, and the differences between the elemental carbon results from the HS cassette and the standard three-piece cassette were within statistical error. The limit of detection for Airtec measurements improved by approximately 15 times, and the elemental carbon results with the HS cassette between the Airtec and NIOSH method 5040 were within statistical agreement. When used in the Airtec monitor, the high-sensitivity cassette showed promise for measuring short-duration spot checks of ambient concentrations but was limited when performing some long-term sampling due to the resultant loss of dynamic range. Only up to 7 mug of elemental carbon was collected onto the HS cassette before the increase in pump backpressure caused the flow fluctuations to exceed targeted values by unacceptable levels. The HS cassette shows promise for effective engineering evaluations of control technologies and strategies and near real-time diesel particulate matter measurements for a variety of occupations.

A study was conducted in an underground mine with the objective to identify, characterize, and source apportion airborne aerosols at the setup face and recovery room during longwall move operations. The focus was on contributions of diesel- and battery-powered heavy-duty vehicles used to transfer equipment between the depleted and new longwall panels and diesel-powered light-duty vehicles used to transport personnel and materials to various locations within the mine. Aerosols at the setup face were found to be distributed among diesel combustion-generated submicrometer and mechanically generated coarse aerosols. According to the data, the submicrometer aerosols downstream of the setup face were sourced to diesel exhaust emitted by vehicles operated inside and outside of the panel. Depending on the intensity of the activities on the panel, the outby sources contributed between 12.5 and 99.6% to the average elemental carbon mass flow at the setup face and recovery room. Extensively used light-duty vehicles contributed measurably to the elemental carbon concentrations at the setup face. The number concentrations of aerosols downstream of the setup face were associated with aerosols generated by combustion in diesel engines operated in the shield haulage loop and/or outside of the longwall panels. Entrainment of road dust by diesel or battery-powered load-haul-dump vehicles operated near the measurement site appears to be the primary source of mass concentrations of aerosols. The findings of this study should help the underground mining industry in its efforts to reduce exposures of miners to diesel and coarse aerosols.

A study was conducted in an underground mine with the objective to assess relative contributions of different types and categories of diesel-powered vehicles to submicron aerosol concentrations and to assess the effectiveness of selected diesel particulate matter control strategies and technologies. The net contributions of each of six heavy-duty (HD) vehicles, five light-duty (LD) vehicles, and the effects of disposable filter elements (DFEs), a sintered metal filter (SMF) system, and repowering were assessed using isolated zone methodology. On average, the HD vehicles powered by engines that were not retrofitted with filtration systems contributed approximately three times more to the number of aerosols and six times more to elemental carbon (EC) mass concentrations than LD vehicles powered by engines that were not retrofitted with filtration systems. Replacing an Environmental Protection Agency (EPA) pre-Tier engine in the non-permissible HD vehicle with an EPA Tier 3 engine resulted in 63% lower EC concentrations and 41% lower aerosol number concentrations. The evaluated filtration system with DFEs reduced the contribution of diesel-powered vehicles to number concentrations of aerosols by 77 to 92% and the average EC concentrations by 95%. The SMF reduced the contribution of diesel-powered vehicles to number concentrations of aerosols and EC concentrations by 93 and 95%, respectively. When compared with older units, one of the newer model personnel carriers contributed noticeably less to EC mass concentrations but almost equally to the number concentrations of diesel aerosols in the mine air. The second newer type of alternative personnel carrier vehicle contributed more to number and EC mass concentrations than the old-style personnel carrier. The LD vehicle powered by an EPA Tier 4f engine equipped with a DPF system contributed least of all tested vehicles to aerosol number and EC mass concentrations. This information is critical to the efforts of the underground mining industry to reduce exposures of workers to diesel aerosols.

A study was conducted to examine the potential of diesel emissions control strategies based on retrofitting existing power packages with exhaust aftertreatment devices and repowering with advanced power packages. The retrofit systems, a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF), were evaluated individually using a US EPA tier 2 (ter 2) engine operated under four steady-state conditions and one transient cycle. The DOC effectively curtailed emissions of CO, and to some extent organic carbon (OC), elemental carbon (EC), and aerosol number concentration. The DPF system offered substantially higher reductions in OC and EC mass and aerosol number concentrations. Both, the DOC and DPF achieved reductions in the aforementioned emissions without adversely affecting emissions of NO2 and nano-sized aerosols. The strategy of repowering with an advanced system was examined using a US EPA tier 4 final (tier 4f) engine equipped with a cooled exhaust gas recirculation system and diesel exhaust fluid-based selective catalytic reduction system, but not with a DPF system. The tier 4f engine contributed substantially less than the tier 2 engine to the EC and OC mass, aerosol number, and CO, NO, and NO2 concentrations. The tier 4f engine was very effective in reducing aerosol mass, NO, and NO2 concentrations, but it was not equally effective in reducing aerosol number concentrations. The implementation of viable exhaust after treatment systems and advanced diesel power packages could be instrumental to the underground mining industry to secure a clean, economical, and dependable source of power for mobile equipment.

The results of laboratory evaluations were used to compare the potential of two alternative, biomass-derived fuels as a control strategy to reduce the exposure of underground miners to aerosols and gases emitted by diesel-powered equipment. The effects of fatty acid methyl ester (FAME) biodiesel and hydrotreated vegetable oil renewable diesel (HVORD) on criteria aerosol and gaseous emissions from an older-technology, naturally aspirated, mechanically controlled engine equipped with a diesel oxidation catalytic converter were compared with those of widely used petroleum-derived, ultralow-sulfur diesels (ULSDs). The emissions were characterized for four selected steady-state conditions. When fueled with FAME biodiesel and HVORD, the engine emitted less aerosols by total particulate mass, total carbon mass, elemental carbon mass and total number than when it was fueled with ULSDs. Compared with ULSDs, FAME biodiesel and HVORD produced aerosols that were characterized by single modal distributions, smaller count median diameters, and lower total and peak concentrations. For the majority of test cases, FAME biodiesel and HVORD favorably affected nitric oxide (NO) and adversely affected nitrogen dioxide (NO2) generation. Therefore, the use of these alternative fuels appears to be a viable tool for the underground mining industry to address the issues related to emissions from diesel engines, and to transition toward more universal solutions provided by advanced engines with integrated exhaust aftertreatment technologies.

Aims of this study were to develop a respirable size-selective sampler for direct-on-filter (DoF) quartz measurement at the end-of-shift (EoS) using a portable Fourier transform infrared (FTIR) spectrometer and to determine its size-selective sampling performance. A new miniaturized sampler has been designed to have an effective particle deposition diameter close to the portable FTIR beam diameter (6-mm). The new sampler (named the EoS cyclone) was constructed using a 3 dimensional printer. The sampling efficiency of the EoS cyclone was determined using polydisperse glass sphere particles and a time-of-flight direct reading instrument. Respirable dust mass concentration and quartz absorbance levels of samples collected with the EoS cyclone were compared to those collected with the 10-mm nylon cyclone. The EoS cyclone operated at a flow rate of 1.2 l min-1 showed minimum bias compared to the international standard respirable convention. The use of the EoS cyclone induced respirable dust mass concentration results similar but significantly larger (5%) than those obtained from samples collected with 10-mm nylon cyclones. The sensitivity of the DoF-FTIR analysis in estimating quartz was found increased more than 10 times when the samples were collected with the EoS cyclone. The average particle deposition diameter was 8.8 mm in sixty samples. The newly developed user friendly EoS cyclone may provide a better sampling strategy in quartz exposure assessment with faster feedback.

This article assesses whether there are race differences in functional health among Hispanic women in the United States; ascertains whether the race differences in functional health vary by age; and examines the extent to which race differences in functional health are attributable to key dimensions of demographic, geographic, and socioeconomic heterogeneity. The analysis is based on 15 years of aggregated data from the National Health Interview Survey. Both U.S.- and foreign-born Black and other race Hispanic women display a higher level of functional limitations than their White Hispanic counterparts. There is little evidence that such health differences widen with age. U.S.-born Black Hispanic women, however, suffer from a high burden of functional limitations across the adult age range. This research speaks to the need for greater attention to racial differences in health among Hispanics and particularly so within the U.S.-born segment of this rapidly aging population.

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent.

The study was conducted to assess the potential of hydrotreated vegetable oil renewable diesel (HVORD) as a control strategy to reduce exposure of workers to diesel aerosols and gases. The effects of HVORD on criteria aerosol and gaseous emissions were compared with those of ultralow sulfur diesel (ULSD). The results of comprehensive testing at four steady-state conditions and one transient cycle were used to characterize the aerosol and gaseous emissions from two older technology engines: (1) a naturally aspirated mechanically controlled and (2) a turbocharged electronically controlled engine. Both engines were equipped with diesel oxidation catalytic converters (DOCs). For all test conditions, both engines emitted measurably lower total mass concentrations of diesel aerosols, total carbon, and elemental carbon when HVORD was used in place of ULSD. For all test conditions, the reductions in total mass concentrations were more substantial for the naturally aspirated than for the turbocharged engine. In the case of the naturally aspirated engine, HVORD also favorably affected total surface area of aerosols deposited in the alveolar region of human lungs (TSAADAR) and the total number concentrations of aerosols. In the case of the turbocharged electronically controlled engine, for some of the test conditions HVORD adversely affected the TSAADAR and total number concentrations of aerosols. In the majority of the test cases involving the naturally aspirated mechanically controlled engine, HVORD favorably affected carbon dioxide (CO2), nitrogen oxides (NOX), and nitric oxide (NO) concentrations, but adversely affected NO2 and total hydrocarbon concentrations, while the effects of the fuels on carbon monoxide (CO) concentrations were masked by the effects of DOC. In the case of the turbocharged electronically controlled engine, the CO2, CO, NOX, NO, and total hydrocarbon concentrations were generally lower when HVORD was used in place of ULSD. The effects of the fuels on NO2 concentrations were masked by the more prominent effects of DOC.

A series of laboratory tests were conducted to assess the effects of Fe-containing fuel additives on aerosols emitted by a diesel engine retrofitted with a sintered metal filter (SMF) system. Emission measurements performed upstream and downstream of the SMF system were compared, for cases when the engine was fueled with neat ultralow sulfur diesel (ULSD) and with ULSD treated with two formulations of additives containing Fe-based catalysts. The effects were assessed for four steady-state engine operating conditions and one transient cycle. The results showed that the SMF system reduced the average total number and surface area concentrations of aerosols by more than 100-fold. The total mass and elemental carbon results confirmed that the SMF system was indeed very effective in the removal of diesel aerosols. When added at the recommended concentrations (30 p.p.m. of iron), the tested additives had minor adverse impacts on the number, surface area, and mass concentrations of filter-out (FOut) aerosols. For one of the test cases, the additives may have contributed to measurable concentrations of engine-out (EOut) nucleation mode aerosols. The additives had only a minor impact on the concentration and size distribution of volatile and semi-volatile FOut aerosols. Metal analysis showed that the introduction of Fe with the additives substantially increased Fe concentration in the EOut, but the SMF system was effective in removal of Fe-containing aerosols. The FOut Fe concentrations for all three tested fuels were found to be much lower than the corresponding EOut Fe concentrations for the case of untreated ULSD fuel. The results support recommendations that these additives should not be used in diesel engines unless they are equipped with exhaust filtration systems. Since the tested SMF system was found to be very efficient in removing Fe introduced by the additives, the use of these additives should not result in a measurable increase in emissions of de novo generated Fe-containing aerosols. The findings from this study should promote a better understanding of the benefits and challenges of using sintered metal systems and fuel additives to control the exposure of underground miners and other workers to diesel aerosols and gases.

The contribution of heavy-duty haulage trucks to the concentrations of aerosols and criteria gases in underground mine air and the physical properties of those aerosols were assessed for three fuel blends made with fatty acid methyl esters biodiesel and petroleum-based ultra-low-sulfur diesel (ULSD). The contributions of blends with 20, 50, and 57% of biodiesel as well as neat ULSD were assessed using a 30-ton truck operated over a simulated production cycle in an isolated zone of an operating underground metal mine. When fueled with the B20 (blend of biodiesel with ULSD with 20% of biodiesel content), B50 (blend of biodiesel with ULSD with 50% of biodiesel content), and B57 (blend of biodiesel with ULSD with 57% of biodiesel content) blends in place of ULSD, the truck's contribution to mass concentrations of elemental and total carbon was reduced by 20, 50, and 61%, respectively. Size distribution measurements showed that the aerosols produced by the engine fueled with these blends were characterized by smaller median electrical mobility diameter and lower peak concentrations than the aerosols produced by the same engine fueled with ULSD. The use of the blends resulted in number concentrations of aerosols that were 13-29% lower than those when ULSD was used. Depending on the content of biodiesel in the blends, the average reductions in the surface area concentrations of aerosol which could be deposited in the alveolar region of the lung (as measured by a nanoparticle surface area monitor) ranged between 6 and 37%. The use of blends also resulted in slight but measurable reductions in CO emissions, as well as an increase in NOX emissions. All of the above changes in concentrations and physical properties were found to be correlated with the proportion of biodiesel in the blends.

The use of biodiesel (BD) or its blends with petroleum diesel (D) is considered to be a viable approach to reduce occupational and environmental exposures to particulate matter (PM). Due to its lower particulate mass emissions compared to D, use of BD is thought to alleviate adverse health effects. Considering BD fuel is mainly composed of unsaturated fatty acids, we hypothesize that BD exhaust particles could induce pronounced adverse outcomes, due to their ability to readily oxidize. The main objective of this study was to compare the effects of particles generated by engine fueled with neat BD and neat petroleum-based D. Biomarkers of tissue damage and inflammation were significantly elevated in lungs of mice exposed to BD particulates. Additionally, BD particulates caused a significant accumulation of oxidatively modified proteins and an increase in 4-hydroxynonenal. The up-regulation of inflammatory cytokines/chemokines/growth factors was higher in lungs upon BD particulate exposure. Histological evaluation of lung sections indicated presence of lymphocytic infiltrate and impaired clearance with prolonged retention of BD particulate in pigment laden macrophages. Taken together, these results clearly indicate that BD exhaust particles could exert more toxic effects compared to D.

Using biodiesel in place of petroleum diesel is considered by several underground metal and nonmetal mine operators to be a viable strategy for reducing the exposure of miners to diesel particulate matter. This study was conducted in an underground experimental mine to evaluate the effects of soy methyl ester biodiesel on the concentrations and size distributions of diesel aerosols and nitric oxides in mine air. The objective was to compare the effects of neat and blended biodiesel fuels with those of ultralow sulfur petroleum diesel. The evaluation was performed using a mechanically controlled, naturally aspirated diesel engine equipped with a muffler and a diesel oxidation catalyst. The effects of biodiesel fuels on size distributions and number and total aerosol mass concentrations were found to be strongly dependent on engine operating conditions. When fueled with biodiesel fuels, the engine contributed less to elemental carbon concentrations for all engine operating modes and exhaust configurations. The substantial increases in number concentrations and fraction of organic carbon (OC) in total carbon over the baseline were observed when the engine was fueled with biodiesel fuels and operated at light-load operating conditions. Size distributions for all test conditions were found to be single modal and strongly affected by engine operating conditions, fuel type, and exhaust configuration. The peak and total number concentrations as well as median diameter decreased with an increase in the fraction of biodiesel in the fuels, particularly for high-load operating conditions. The effects of the diesel oxidation catalyst, commonly deployed to counteract the potential increase in OC emissions due to use of biodiesel, were found to vary depending upon fuel formulation and engine operating conditions. The catalyst was relatively effective in reducing aerosol number and mass concentrations, particularly at light-load conditions, but also showed the potential for an increase in nitrogen dioxide concentrations at high-load modes.

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element. The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems. copyright 2009 American Chemical Society.