Diesel Particulate Matter Concentrations Research Articles

DPM dispersion inside a single straight entry using dynamic mesh model

Three-dimensional simulations of diesel particulate matter (DPM) distribution inside a single straight entry for the Load-Haul-Dump loader (LHD)-truck loading and truck hauling operations were conducted by using ANSYS FLUENT computational fluid dynamics software. The loading operation was performed for a fixed period of 3 min. The dynamic mesh technique in FLUENT was used to study the impact of truck motion on DPM distribution. The resultant DPM distributions are presented for the cases when the truck were driving upstream and downstream of the loading face. Interesting phenomena were revealed in the study including the piston effect, layering of DPM in the roof region, and backflow of diesel exhaust against ventilation. The results from the simulation can be used to determine if the areas inside the face area and straight entry exceed the current U.S. regulatory requirement for DPM concentration (>160 µg/m3). This research can guide the selection of DPM reduction strategies and improve the working practices for the underground miners.

Association between prenatal exposure to ambient diesel particulate matter and perchloroethylene with children's 3rd grade standardized test scores

The objective of this research was to determine if prenatal exposure to two common urban air pollutants, diesel and perchloroethylene, affects children's 3rd grade standardized test scores in mathematics and English language arts (ELA). Exposure estimates consisted of annual average ambient concentrations of diesel particulate matter and perchloroethylene obtained from the Environmental Protection Agency's 1996 National Air Toxics Assessment for the residential census tract at birth. Outcome data consisted of linked birth and educational records for 201,559 singleton, non-anomalous children born between 1994 and 1998 who attended New York City public schools. Quantile regression models were used to estimate the effects of these exposures on multiple points within the continuous distribution of standardized test scores. Modified Poisson regression models were used to calculate risk ratios (RR) and 95% confidence intervals (CI) of failing to meet curricula standards, an indicator derived from test scores. Models were adjusted for a number of maternal, neighborhood and childhood factors. Results showed that math scores were approximately 6% of a standard deviation lower for children exposed to the highest levels of both pollutants as compared to children with low levels of both pollutants. Children exposed to high levels of both pollutants also had the largest risk of failing to meet math test standards when compared to children with low levels of exposure to the pollutants (RR 1.10 95%CI 1.07,1.12 RR high perchloroethylene only 1.03 95%CI 1.00,1.06; RR high diesel PM only 1.02 95%CI 0.99,1.06). There was no association observed between exposure to the pollutants and failing to meet ELA standards. This study provides preliminary evidence of associations between prenatal exposure to urban air pollutants and lower academic outcomes. Additionally, these findings suggest that individual pollutants may additively impact health and point to the need to study the collective effects of air pollutant mixtures. Key Words: air toxics, academic outcomes, urban health, tetrachloroethylene, air pollutant mixtures

DPM simulation in an underground entry: Comparison between particle and species models

The diesel particulate matter (DPM) emission from diesel powered equipment in underground mines can cause health hazards including cancer to the miners. The understanding of the DPM propagation pattern under realistic mining condition is required for selecting proper DPM control strategies and to improve working practices in underground mines. In this paper, three dimensional simulations of DPM emission from the exhaust tail pipe of a load-haul-dump (LHD) vehicle and its subsequent distribution inside an isolated zone in the typical underground mine are carried out using two different solution models available in Ansys Fluent. The incoming fresh air into the isolated zone is treated as a continuous phase and DPM is treated either as a continuous phase (gas) or as a secondary discrete phase (particle). Species transport model is used when DPM is treated as gas and discrete phase model is used when DPM is assumed to behave like a particle. The distributions of DPM concentration inside the isolated zone obtained from each method are presented and compared. From the comparison results, an accurate and economical solution technique for DPM evaluation can be selected.

A diesel particulate matter dispersion study inside a single dead end entry using dynamic mesh model

Three-dimensional simulations of diesel particulate matter (DPM) distribution inside a single dead end entry with a push-pull system for the load-haul-dump (LHD)-truck loading and truck hauling operations were carried out using ANSYS FLUENT computational fluid dynamics (CFD) software. The loading operation was performed for a fixed period of time. Then dynamic mesh technique in FLUENT was used to study the impact of truck motion on DPM distribution. The resultant DPM distributions are presented for the cases when the vehicles were fitted with and without diesel particulate filters (DPF). The results from the simulation can be used to determine if the areas inside the single dead end entry exceed the current U.S. regulatory requirement for DPM concentration (160 µg/m3). This research can guide the selection of DPM reduction strategies and improve the working practices for the underground miners.

Ambient and Emission Trends of Toxic Air Contaminants in California.

After initiating a toxic air contaminant (TAC) identification and control program in 1984, the California Air Resources Board adopted regulations to reduce TAC emissions from cars, trucks, stationary sources, and consumer products. This study quantifies ambient concentration and emission trends for the period 1990-2012 for seven TACs that are responsible for most of the known cancer risk associated with airborne exposure in California. Of these seven, diesel particulate matter (DPM) is the most important; however DPM is not measured directly. Based on a novel surrogate method, DPM concentrations declined 68%, even though the state's population increased 31%, diesel vehicle-miles-traveled increased 81%, and the gross state product (GSP) increased 74%. Based on monitoring data, concentrations of benzene, 1,3-butadiene, perchloroethylene, and hexavalent chromium declined 88-94%. Also, the ambient and emissions trends for each of these four TACs were similar. Furthermore, these declines generally occurred earlier in California than elsewhere. However, formaldehyde and acetaldehyde, which are formed in the air photochemically from volatile organic compounds (VOCs), declined only 20-21%. The collective cancer risk from exposure to these seven reviewed TACs declined 76%. Significant reduction in cancer risk to California residents from implementation of air toxics controls (especially for DPM) is expected to continue.

Evaluation of Diesel Exhaust Continuous Monitors in Controlled Environmental Conditions

Diesel exhaust (DE) contains a variety of toxic air pollutants, including diesel particulate matter (DPM) and gaseous contaminants (e.g., carbon monoxide (CO)). DPM is dominated by fine (PM2.5) and ultrafine particles (UFP), and can be representatively determined by its thermal-optical refractory as elemental carbon (EC) or light-absorbing characteristics as black carbon (BC). The currently accepted reference method for sampling and analysis of occupational exposure to DPM is the National Institute for Occupational Safety and Health (NIOSH) Method 5040. However, this method cannot provide in-situ short-term measurements of DPM. Thus, real-time monitors are gaining attention to better examine DE exposures in occupational settings. However, real-time monitors are subject to changing environmental conditions. Field measurements have reported interferences in optical sensors and subsequent real-time readings, under conditions of high humidity and abrupt temperature changes. To begin dealing with these issues, we completed a controlled study to evaluate five real-time monitors: Airtec real-time DPM/EC Monitor, TSI SidePak Personal Aerosol Monitor AM510 (PM2.5), TSI Condensation Particle Counter 3007, microAeth AE51 BC Aethalometer, and Langan T15n CO Measurer. Tests were conducted under different temperatures (55, 70, and 80°F), relative humidity (10, 40, and 80%), and DPM concentrations (50 and 200 μg/m3) in a controlled exposure facility. The 2-hr averaged EC measurements from the Airtec instrument showed relatively good agreement with NIOSH Method 5040 (R2 = 0.84; slope = 1.17±0.06; N = 27) and reported ∼17% higher EC concentrations than the NIOSH reference method. Temperature, relative humidity, and DPM levels did not significantly affect relative differences in 2-hr averaged EC concentrations obtained by the Airtec instrument vs. the NIOSH method (p < 0.05). Multiple linear regression analyses, based on 1-min averaged data, suggested combined effects of up to 5% from relative humidity and temperature on real-time measurements. The overall deviations of these real-time monitors from the NIOSH method results were ≤20%. However, simultaneous monitoring of temperature and relative humidity is recommended in field investigations to understand and correct for environmental impacts on real-time monitoring data.

Monitoring of atmospheric gaseous and particulate polycyclic aromatic hydrocarbons in South African platinum mines utilising portable denuder sampling with analysis by thermal desorption–comprehensive gas chromatography–mass spectrometry

Concentrations of diesel particulate matter and polycyclic aromatic hydrocarbons (PAHs) in platinum mine environments are likely to be higher than in ambient air due to the use of diesel machinery in confined environments. Airborne PAHs may be present in gaseous or particle phases each of which has different human health impacts due to their ultimate fate in the body. Here we report on the simultaneous sampling of both phases of airborne PAHs for the first time in underground platinum mines in South Africa, which was made possible by employing small, portable denuder sampling devices consisting of two polydimethylsiloxane (PDMS) multi-channel traps connected in series separated by a quartz fibre filter, which only require small, battery operated portable personal sampling pumps for air sampling. Thermal desorption coupled with comprehensive gas chromatography–mass spectrometry (TD–GC×GC–TofMS) was used to analyse denuder samples taken in three different platinum mines. The samples from a range of underground environments revealed that PAHs were predominantly found in the gas phase with naphthalene and mono-methylated naphthalene derivatives being detected at the highest concentrations ranging from 0.01 to 18μgm−3. The particle bound PAHs were found in the highest concentrations at the idling load haul dump vehicle exhausts with a dominance of fluoranthene and pyrene. Particle associated PAH concentrations ranged from 0.47 to 260ngm−3 and included benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and benzo[ghi]perylene. This work highlights the need to characterise both phases in order to assess occupational exposure to PAHs in this challenging sampling environment.

Evaluation of a Wearable Monitor for Measuring Real-Time Diesel Particulate Matter Concentrations in Several Underground Mines

The standard method for determining diesel particulate matter (DPM) exposures in underground metal/nonmetal mines provides the average exposure concentration for an entire working shift, and it can take weeks to obtain results. This approach is problematic because, although it reports that an overexposure has occurred, it fails to provide critical information about cause or prevention. Conversely, real-time measurement would provide miners with timely information to identify the major factors contributing to overexposures and would allow engineering controls to be deployed immediately. Due to these potential benefits, the National Institute for Occupational Safety and Health (NIOSH) developed a wearable instrument that measures real-time elemental carbon (EC) concentrations (EC is a DPM surrogate) via laser extinction. This instrument was later constructed into a commercial version (Airtec). This article evaluates the Airtec's performance in several underground metal/nonmetal mines by comparing it to the standard method for determining DPM exposures (NIOSH method 5040). The instrument was found to meet the NIOSH accuracy criteria and to show no statistical difference from NIOSH method 5040 results. In addition, the instrument's measurements were found to be unaffected by dust and humidity.

Gene-Environment Interactions and the Risk of Cervical Dysplasia: The Role of DNA Repair Genes and Diesel Particulate Matter

Background: There is growing evidence that air pollution, including diesel particulate matter (DPM), is associated with cervical cancer and dysplasia. One potential mechanism for DPM-induced mutagenesis is related to DNA damage. Therefore, we hypothesized that genetic variation in the DNA repair pathway may modify cervical dysplasia risk. Aim: Determine the role of DNA repair gene-DPM interactions on the risk of cervical dysplasia. Methods: Our study population was drawn from women participating in a multi-center Phase II clinical trial between 2000 and 2004, of which 129 had cervical dysplasia (cases) and 177 did not (controls). Census tract-level estimates of DPM concentrations were obtained from the United States Environmental Protection Agency 1999 National-Scale Air Toxics Assessment. Exposure was based on residence at clinic visit and was categorized as low (&lt;75th percentile) or high (?75th percentile). Genotyping on 768 single nucleotide polymorphisms (SNPs) in 13 DNA repair genes was performed using the Illumina Golden Gate platform. We utilized a 2-step approach to evaluate gene-environment interactions. In step 1, we examined the association between each SNP (G) and DPM exposure (E). SNPs where p&lt;0.02 were then included in step 2, a case-control analysis of GxE interactions using logistic regression models. Results: In step 1 of our analysis, we identified seven SNPs that were associated with exposure. In step 2 of our analysis, there was one statistically significant interaction between NBN rs2735388 and DPM exposure (p=0.03). Specifically, women who were NBN rs2735388 AA and had high DPM exposure were more likely to have cervical dysplasia (odds ratio=2.90, 95% confidence interval: 1.17-7.20) compared to women who were TT/TA and had low DPM exposure. Conclusions: In one of the first assessments of gene-air pollution interactions and cervical dysplasia, we found that DPM-associated disease risk was modified by genetic variation in the DNA repair pathway.

Spatial variations of particulate matter and air toxics in communities adjacent to the Port of Oakland

The Bay Area Air Quality Management District (BAAQMD) sponsored the West Oakland Monitoring Study (WOMS) to provide supplemental air quality monitoring that will be used by the BAAQMD to evaluate local-scale dispersion modeling of diesel emissions and other toxic air contaminants for the area within and around the Port of Oakland. The WOMS was conducted during two seasonal periods of 4 weeks in summer 2009 and winter 2009/2010. Monitoring data showed spatial patterns of pollutant concentrations that were generally consistent with proximity to vehicle traffic. Concentrations of directly emitted pollutants were highest on heavily traveled roads with consistently lower concentrations away from the roadways. Pollutants that have higher emission rates from diesel trucks (nitric oxide, black carbon) tended to exhibit sharper gradients than pollutants that are largely associated with gasoline vehicles, such as carbon monoxide and volatile organic compounds, including benzene, toluene, ethylbenzene, and xylenes (BTEX). BTEX concentrations in West Oakland were similar to those measured at the three air toxics monitoring network sites in the Bay Area (San Francisco, Fremont, and San Jose). Aldehyde levels were higher in Fremont and San Jose than in West Oakland, reflecting greater contributions from photo-oxidation of hydrocarbons downwind of the Bay Area. A 2005 modeling-based health risk assessment of diesel particulate matter concentrations is consistent with aerosol carbon concentrations measured during the WOMS after adjusting for recent mitigation measures and improved estimates of heavy-duty truck traffic volumes. Implications: The WOMS taken in combination with other recent studies indicates that focused grant–funded diesel reduction projects, new regulatory requirements, and focused enforcement near the Port of Oakland have been effective. However, the study also showed higher pollutant concentrations along major roadways in West Oakland, especially in areas with high traffic volumes of diesel trucks.

Emission Scenarios and the Health Risks Posed by Priority Mobile Air Toxics in an Urban to Regional Area: An Application in Nashville, Tennessee

Toxic air pollutants, also known as hazardous air pollutants, are those that are known or suspected to cause cancer or other serious health effects, such as birth defects or adverse environmental outcomes. The aim of this research was to predict air toxics related health risks due to different emission scenarios by linking Models-3/CMAQ and cancer risk assessments. To demonstrate the effectiveness of this approach, this study was performed on the priority mobile source air toxics (PMSAT) of benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and diesel particulate matter (DPM), based on data from 2003. The analysis was carried out in the eastern US, and mainly in Nashville, TN. Ten emissions scenarios were examined, including a 2020 scenario with the effects of on-road mobile source regulations. The results show that DPM poses a cancer risk that is 4.2 times higher than the combined total cancer risk from all of four other PMSAT. These high cancer risk levels are mainly due to non-road sources (57.9%). The main cancer risk from acetaldehyde, benzene, formaldehyde, and 1,3-butadiene (4HAPs) is due to biogenic sources, which account for 32.2% of this risk, although these cannot be controlled. Excluding DPM, the main on-road cancer risk contribution was due to the air toxics generated by gasoline light duty vehicles (LDVs), principally benzene and 1,3-butadiene. The scenario for 2020 showed reductions in the adverse health effects related to DPM and 4HAPs of 32.8 and 19.4%, respectively. This research provides strong evidence that reducing ambient DPM concentrations will lead to greater improvements in human health than other air toxics, indicating that better technologies and regulations must be applied to mobile diesel engines, as these have more significant adverse health effects than non-road diesel sources.

Comparison of real-time and traditional monitoring methods for diesel particulate matter in underground metal mines: A meta-analysis

Objective To conduct a meta-analysis of published studies to determine if a real-time instrument can be used as a screening tool to estimate the concentrations of diesel particulate matter (DPM) in air within an underground mine workplace. The instrument chosen for review is the TSI DustTrak. The DustTrak was chosen because of the growing popularity, ease of use, and relative low cost as compared to other real-time instruments used in the underground mining industry. Determination of acceptability for DustTrak use would be based on comparison of instrument results to monitoring results from the currently accepted pump-filter air sampling methods for DPM. Methods After a comprehensive literature search, a total of two studies meeting requirements for a meta-analysis on performance of the DustTrak were identified and used for this analysis. Results Meta-analysis of the available DPM exposure monitoring data resulted in a Combined Pearson's Correlation Coefficient (CPCC) of 0.893 (p Conclusions The results from this meta-analysis are supportive of the DustTrak as an acceptable supplementary sampler (e.g., used to verify the adequacies of exposure controls) for providing acceptably accurate real-time concentration levels of DPM in air in an underground mining operation. Although the DustTrak correlates well with the NIOSH method, its monitoring results do consistently read higher than the NIOSH method.

Real-time diesel particulate matter ambient monitoring in underground mines

A real-time Diesel Particulate Matter (DPM) monitor has been developed on the base of the successful National Institute of Occupational Health and Safety (NIOSH) designed Personal Dust Monitor (PDM) unit. The objectives of a recently completed Australian Coal Association Research Program (ACARP) study was to modify the PDM to measure the submicrometre fraction of the aerosol in a real-time monitoring underground instrument. Mine testing focused on use of the monitor in engineering evaluations of Longwall (LW) moves demonstrated how DPM concentrations from vehicles fluctuate under varying ventilation and operational conditions. The strong influence of mine ventilation systems is reviewed. Correlation between the current SKC DPM measurement system and real-time DPM monitors were conducted and results from eight mines show a correlation between elemental carbon (EC) and the new monitor DPM mass ranging from 0.45 to 0.82 with R 2>0.86 in all but two cases. This differences in suspected to be due to variations from mine to mine in aspects such as mine atmospheric contamination, vehicle fleet variations, fuel type, engine maintenance, engine combustion efficiency, engine behavior or interference from other submicrometre aerosol. Real-time monitoring clearly reflects the movement of individual diesel vehicles and allows pin-pointing of high exposure zones such as those encountered where various vehicles engage in intense work in areas of constrained or difficult ventilation. DPM shift average monitoring approaches do not readily allow successful engineering evaluation exercises to determine acceptability of pollution levels. Identification of high DPM concentration zones allows efficient modification of mine ventilation, operator positioning and other work practices to reduce miners’ exposures without waiting for laboratory analysis results.

DPM dissipation experiment at MST’s experimental mine and comparison with CFD simulation

Diesel Particulate Matter (DPM) is regulated in the U.S. for both underground coal and metal/nonmetal mines. Today, many underground mines still face difficulty in compliance with DPM regulations. The DPM research carried out in Missouri University of Science and Technology (MST) is to use computational fluid dynamics (CFD) to study the DPM distribution in commonly used face areas. The result is expected to be used for selection of DPM reduction strategies and better working practices, which can help the underground mines to meet regulation limits and improve the working environment for the miners. An experiment was conducted at MST’s Experimental Mine to validate CFD simulation. DPM was collected at four locations downstream of a stationary diesel engine. The experiment data were then compared with the CFD simulation results. The comparison shows that CFD simulation can forecast the location of DPM concentration with practical accuracy (less than 0.15 m). CFD can be used to further study DPM distribution in commonly used working faces and give guidance to DPM reduction.

Application and performance test of a micro-machined unipolar charger for real-time measurements of exhaust particles from a diesel engine vehicle

Characterization of particulate matter (PM) emitted from diesel vehicle exhaust requires a real-time measurement sensor to record particle concentrations under transient tests. Recently, a micro-machined unipolar charger (MUC) based on a micro-electromechanical system (MEMS) was introduced and evaluated to test aerosol particles on a laboratory scale. We present the performance characteristics of the MUC for its potential use as a sensor for diesel PM emissions. A correlation equation was derived from particle loss experiments and tandem differential mobility analyzer (TDMA) measurements in the laboratory, which was used to convert the current measurement datum into a total particle number concentration. Under various idling and driving conditions of a diesel vehicle, the electrical signals from the MUC were verified to have followed the trend of the total number concentrations of diesel PM measured using a condensation particle counter (CPC). When the diesel PM concentrations measured using the CPC were within the range of 2×10 4–2×10 5 #/cm 3, the total number concentrations, estimated using a correlation equation, were in agreement with the CPC data.

Mutagenicity of Diesel Exhaust Particles from an Engine with Differing Exhaust After Treatments

This study was conducted to investigate the effects of engine operating conditions and exhaust aftertreatments on the mutagenicity of diesel particulate matter (DPM) collected directly in an underground mine environment. A number of after-treatment devices are currently used on diesel engines in mines, but it is critical to determine whether reductions in DPM concentrations result in a corresponding decrease in adverse health effects. An eddy-current dynamometer was used to operate naturally aspirated mechanically controlled engine at several steady-state conditions. The samples were collected when the engine was equipped with a standard muffler, a diesel oxidation catalytic converter, two types of uncatalyzed diesel particulate filter systems, and three types of disposable diesel particulate filter elements. Bacterial gene mutation activity of DPM was tested on acetone extracts using the Ames Salmonella assay. The results indicated strong correlation between engine operating conditions and mutagenic activity of DPM. When the engine was fitted with muffler, the mutagenic activity was observed for the samples collected from light-load, but not heavy-load operating conditions. When the engine was equipped with a diesel oxidation catalyst, the samples did not exhibit mutagenic activity for any of four engine operating conditions. Mutagenic activity was observed for the samples collected when the engine was retrofitted with three types of disposable filters and sintered metal diesel particulate filter and operated at light load conditions. However, those filtration systems substantially reduced the concentration-normalized mutagenic activity from the levels observed for the muffler.

Enhancement of diesel particulate matter collection in an electrostatic water-spraying scrubber

Marine diesel engines are major sources of air pollution. They emit a large amount of pollutants, including diesel particulate matter (DPM), carbon oxide (CO x ), unburned hydrocarbons (HC), nitrogen oxide (NO x ), sulfur oxide (SO x ), and other products of combustion. Among these, DPM may cause respiratory and mutagenic diseases in humans, including lung and bladder cancer (see Donaldson et al. J Aerosol Sci 29:553–560, 1998). In this study, experiments were performed with an electrostatic water-spraying scrubber (EWSS) to evaluate its effectiveness for the collection of mass- and number-based DPM emissions from a marine diesel engine. The results show that the collection efficiency of the scrubber increases as the engine load increases due to an increase in the large DPM concentration and an increase in the amount of DPM collected by the charged droplets. The effect of water spraying performance on DPM collection at constant engine load was investigated experimentally. The strength of the electrical attraction between the charged water droplets and the charged DPM within the scrubber led to a significant increase in total DPM collection efficiency (up to 4–7 times). In addition, the total DPM collection efficiency was found to be directly related to the corona power, the electrical properties of water, water spraying performance and engine load. The EWSS appears to be a promising alternative method for controlling mass-based as well as number-based DPM emissions.

Characteristics of submarine engine diesel particulates in the maritime environment

Measurements of diesel particulate emissions from maritime sources are rare, although this form of transportation causes significant air pollution. However, unlike the land environment, the nautical environment is free of interference from other combustion sources. Continuous measurements of diesel particulate matter (DPM) were recently conducted in conventional diesel-electric submarines. The average DPM concentration in the engine room was 150 μg m −3, with particle size distributions in the range of 0.5–2 μm. Chemical speciation of elemental carbon (EC), organic carbon (OC) and total carbon (TC) were determined. Both the National Institute of Occupational Safety and Health (NIOSH) Method 5040 and the Interagency Monitoring of Protected Visual Environment (IMPROVE) method showed EC as being composed of 45% TC. Soluble inorganic components of DPM were characterised. After correction for salt contribution, TC was found to be of 80% DPM. EC, TC and DPM were found to conform to the characteristics defined for exposure and risk assessments by government authorities.

Investigation into pedestrian exposure to near-vehicle exhaust emissions.

BackgroundInhalation of diesel particulate matter (DPM) is known to have a negative impact on human health. Consequently, there are regulations and standards that limit the maximum concentrations to which persons may be exposed and the maximum concentrations allowed in the ambient air. However, these standards consider steady exposure over large spatial and time scales. Due to the nature of many vehicle exhaust systems, pedestrians in close proximity to a vehicle's tailpipe may experience events where diesel particulate matter concentrations are high enough to cause acute health effects for brief periods of time.MethodsIn order to quantify these exposure events, instruments which measure specific exhaust constituent concentrations were placed near a roadway and connected to the mouth of a mannequin used as a pedestrian surrogate. By measuring concentrations at the mannequin's mouth during drive-by events with a late model diesel truck, a representative estimate of the exhaust constituent concentrations to which a pedestrian may be exposed was obtained. Typical breathing rates were then multiplied by the measured concentrations to determine the mass of pollutant inhaled.ResultsThe average concentration of diesel particulate matter measured over the duration of a single drive-by test often exceeded the low concentrations used in human clinical studies which are known to cause acute health effects. It was also observed that higher concentrations of diesel particulate matter were measured at the height of a stroller than were measured at the mouth of a mannequin.ConclusionDiesel particulate matter concentrations during drive-by incidents easily reach or exceed the low concentrations that can cause acute health effects for brief periods of time. For the case of a particularly well-tuned late-model year vehicle, the mass of particulate matter inhaled during a drive-by incident is small compared to the mass inhaled daily at ambient conditions. On a per breath basis, however, the mass of particulate matter inhaled is large compared to the mass inhaled at ambient conditions. Finally, it was determined that children, infants, or people breathing at heights similar to that of a passing vehicle's tailpipe may be exposed to higher concentrations of particulate matter than those breathing at higher locations, such as adults standing up.

Diesel particulate matter, lung cancer, and asthma incidences along major traffic corridors in MA, USA: A GIS analysis

By examining the census tracts and towns that are intersected by Massachusetts’ major highway corridors, Diesel and Health along Massachusetts’ Highway Corridors ascertains whether these areas contain significantly higher rates of diesel particulate matter (DPM), lung cancer, and asthma. DPM was significantly higher for corridor towns than non-corridor towns. Hot spot analysis revealed statistically significant clustering of elevated DPM concentrations and asthma incidence in certain towns. The location of these towns was compared to the location of environmental justice neighborhoods. The authors recommend a series of steps that can be taken by policy makers and planners to curb DPM emissions.