Effect of Fuel Properties on Mutagenic Activity in Extracts of Heavy-duty Diesel Exhaust Particulate

The effect of varying fuel properties on the emission of mutagenic materials was studied in diesel exhaust particles from a heavy duty engine run under transient speed and load conditions while using nine fuels varying in aromatics, sulfur and boiling point. Mutagenic activity of the soluble organic fraction (SOF) of the particulate was determined using the Ames Salmonella test system with strain TA98 with and without S9 activation. Increasing mutagenic activity relative to fuel consumed (mutants/lb fuel) or to engine work output (mutants/hp-h) was correlated with increasing fuel aromatics (p < 0.05), but not with fuel sulfur. Increased fuel sulfur levels were correlated with increased amounts of SOF but with decreasing mutagenic activity of the SOF (mutants/microgram SOF) (p < 0.05). As a result, mutants/hp-h were essentially the same for high- and low-sulfur fuels with high aromatics. No association was found between the fuels’ boiling points and the mutagenic activity of the SOF. Mutagenic activity with S9 was generally lower than without, but the correlations were not changed.     

Organic Content of Particulate Matter In Turbine Engine Exhaust

Solid particulate matter, mainly carbon, emitted into the air from the combustion of fossil fuels contains a variety of organic species adsorbed on it. In our examination of these particulates from the combustion of kerosene type fuels in a gas turbine engine, attention was focused on polynuclear aromatic compounds, phenols, nitrosamines, and total organics. Polynuclears were determined by HPLC, GC/MS, and NMR examination. Phenols and nitrosamines were isolated and then measured by gas chromatography using a flame ionization detector and nitrogen detector. Total organics were determined by a backflush chromatographic procedure. The particulates were collected using a high capacity pumping system and 293 mm diameter teflon filters through which was passed up to 43 m³ of exhaust gas. Extraction of the organic matter was done in a Soxhlet extractor using hexane usually. The engine was operated at idle, approach, climb, and takeoff power settings with low sulfur and high sulfur (0.25%) fuels. Most of the PAH were small 3 and 4 fused ring compounds with very few, at low concentrations, of 5 and 6 fused ring species. No nitrosamines were found and except in a few cases, at low levels, no phenols. PNA and total organic levels decreased with increase in a power setting and were higher in the exhaust from low sulfur fuels. Less than 1% of the organic matter emitted by the engine was absorbed on the particulate matter. The body of information presented in the paper is directed to individuals concerned with the nature of emissions from gas turbine engines. The work was supported by a contract with the Environmental Protection Agency.     

Application of a Chemical Mass Balance Receptor Model to Respirable Particulate Matter in Mexico City

Mexico City frequently experiences high levels of air pollution. This is due mainly to its topography and meteorology that suppress pollutant diffusion and dispersion. The atmospheric mixing is extremely poor, especially during the dry winter months. The levels of certain pollutants, such as particulate matter, are of concern since they have severe effects on public health. Visibility deterioration is one of the most noticeable effects in large cities. Biological effects of particulate matter on man and animals, ranging from mild eye irritation to death, have been reported. The effects depend on the size of the particles, their solubility, and toxicity. The main objective of this paper is to present the results of a chemical mass balance receptor model applied to a well-characterized data set of particulate matter collected in the Mexico City Metropolitan Area (MCMA). Samples of particulate matter were collected using a denuder and a Hi-Vol system for the respi-rable fraction and total suspended particles, respectively. In this paper the analysis of a database consisting of the chemical composition of 33 samples of respirable particulate matter (aerosols with diameter less than 2.5 µm) is presented. The 12-hour samples were acquired during day and night periods in a typical medium-income neighborhood from December 19, 1989 through February 5, 1990.     

Effect of fuel properties on mutagenic activity in extracts of heavy-duty diesel exhaust particulate.

The effect of varying fuel properties on the emission of mutagenic materials was studied in diesel exhaust particles from a heavy duty engine run under transient speed and load conditions while using nine fuels varying in aromatics, sulfur and boiling point. Mutagenic activity of the soluble organic fraction (SOF) of the particulate was determined using the Ames Salmonella test system with strain TA98 with and without S9 activation. Increasing mutagenic activity relative to fuel consumed (mutants/lb fuel) or to engine work output (mutants/hp-h) was correlated with increasing fuel aromatics (p less than 0.05), but not with fuel sulfur. Increased fuel sulfur levels were correlated with increased amounts of SOF but with decreasing mutagenic activity of the SOF (mutants/microgram SOF) (p less than 0.05). As a result, mutants/hp-h were essentially the same for high- and low-sulfur fuels with high aromatics. No association was found between the fuels' boiling points and the mutagenic activity of the SOF. Mutagenic activity with S9 was generally lower than without, but the correlations were not changed.     

The Mutagenic Activity of Particulate Organic Matter Collected with a Dilution Sampler at Coal-Fired Power Plants

The Deep Creek Lake Study of 1983 provided an opportunity to obtain emission samples from coal-fired power plants with a dilution sampler for mutagenicity testing. Stack and ambient samples of particulate matter were collected with a dilution sampler at three coal-fired power plants in West Virginia. Samples were sequentially extracted with cyclohexane (CX), dichloromethane (DCM) and acetone (ACE) and tested for mutagenicity in the Ames Salmonella/microsome assay using TA98 (-S9). For the stack samples, the CX, DCM and ACE fractions constituted 1.0, 0.7 and 98.1 percent of the total extractable organic material (EOM), respectively, compared to 28.5, 7.4 and 64.1 percent for the ambient samples. In contrast, the mutagenic activity of the organic fractions was concentrated in the CX and DCM fractions.

The cyclohexane- and dichloromethane-soluble fractions of the stack samples from all locations exhibited mutagenicity when tested in the plate incorporation assay. No significant response was observed with the acetone fraction. When tested with Kado's modification of the preincubation assay, the acetone-soluble fraction did exhibit mutagenic activity comparable to that of the other fractions when expressed in units of revertants per milligram of particular matter. Chemical analyses of one of the acetone-soluble fractions indicated that half of the mass was sulfuric acid while the remainder consisted of C, H and O. More than 30 peaks were detected in the high pressure liquid chromatogram of this fraction.

Although little mutagenic activity was detected in the polar ACE fraction of the diluted stack emissions samples with this single bioassay, in view of the large mass of this fraction, further investigation of the chemical composition and genotoxic activity of this fraction would be prudent.     

Characterization of visibility impacts related to fine particulate matter in Canada

Canada has recently established standards for the management of particulate matter (PM) air quality. National networks currently measure PM mass concentrations and chemical speciation. Methods used in the U.S. IMPROVE network are applied to the 1994--2000 Canadian fine PM data to obtain a regional reconstruction of the visibility based on particle composition. Nationally, the greatest light extinction occurs in the Windsor-Quebec City corridor. Variations in the dominant chemical species responsible for the reduction in visibility are presented for regions across the country. In most regions, sulfate and nitrate contribute most greatly to reduced visibility. The visibility implications of achieving the Canada-Wide Standard (CWS) across the country are evaluated, with the greatest improvement in visibility associated with achieving the CWS in southern Ontario. Elsewhere in the country, achieving the CWS will actually result in deteriorating air quality. Improving current estimates of visibility requires higher spatially and temporally resolved measurements of organic and elemental carbon fractions and particulate nitrate.     

Roadside measurements of size-segregated particulate organic compounds near gasoline and diesel-dominated freeways in Los Angeles,CA

Individual organic compounds such as hopanes and steranes (originating in lube oil) and selected polycyclic aromatic compounds (PAHs) (generated via combustion) found in particulate emissions from vehicles have proven useful in source apportionment of ambient particulate matter (PM). Detailed information on the size-segregated (ultrafine and accumulation mode) chemical characteristics of organic PM during the winter season originating from a pure gasoline traffic freeway (CA-110), and a mixed-fleet freeway with the highest fraction of heavy-duty diesel vehicles in the state of California (I-710) is reported in this study. Hopanes and steranes as well as high molecular weight PAHs such as benzo(ghi)perylene (BgP) and coronene levels are found comparable near these freeways, while elemental carbon (EC) and lighter molecular weight PAHs are found much elevated near I-710 compared to CA-110. The roadway organic speciation data presented here are compared with the emission factors (EFs) measured in the Caldecott tunnel, Berkeley, CA [Phuleria, H.C., Geller, M.D., Fine, P.M., Sioutas, C., 2006. Size-resolved emissions of organic tracers from light- and heavy-duty vehicles measured in a California roadway tunnel. Environmental Science and Technology 40, 4109–4118] for light-duty vehicles (LDVs) and heavy-duty vehicles. Very good agreement is observed between CA-110 measurements and LDV EFs as well as I-710 measurements and corresponding reconstructed EFs from Caldecott tunnel for hopanes and steranes as well as heavier PAHs such as BgP and coronene. Our results, therefore, suggest that the EFs for hopanes and steranes obtained in tunnel environments, where emissions are averaged over a large vehicle-fleet, enable reliable source apportionment of ambient PM, given the overall agreement between the roadway vs tunnel concentrations of these species.     

Mutagenicity evaluation of chemical pesticides

Abstract

Over the last few decades, the use of chemical pesticides has increased dramatically in the U.S. This relatively sudden increase greatly concerns the U.S. Environmental Protection Agency (EPA), since it has the responsibility for ensuring the safety of all pesticides used in the U.S. In response to this concern, EPA has established a review program, the Rebuttable Presumption Against Registration (RPAR), for periodically reassessing the mutagenic and carcinogenic potential of pesticide compounds.

This paper presents a review and evaluation of the data reported in the literature on six chemical pesticides suspect for mutagenic potential. The pesticide chemicals discussed are maleic hydrazide; rotenone; monuron; diallate; triallate, and benomyl.     

Application of a Chemical Mass Balance Receptor Model to Respirable Particulate Matter in Mexico City

Mexico City frequently experiences high levels of air pollution. This is due mainly to its topography and meteorology that suppress pollutant diffusion and dispersion. The atmospheric mixing is extremely poor, especially during the dry winter months. The levels of certain pollutants, such as particulate matter, are of concern since they have severe effects on public health. Visibility deterioration

is one of the most noticeable effects in large cities. Biological effects of particulate matter on man and animals, ranging from mild eye irritation to death, have been reported. The effects depend on the size of the particles, their solubility, and toxicity. The main objective of this paper is to present the results of a chemical mass balance receptor model applied to a well-characterized data set of particulate matter collected in the Mexico City Metropolitan Area (MCMA). Samples of particulate matter were collected using a denuder and a Hi-Vol system for the respirable fraction and total suspended particles, respectively.

In this paper the analysis of a database consisting of the chemical composition of 33 samples of respirable particulate matter (aerosols with diameter less than 2.5 μm) is presented. The 12-hour samples were acquired during day and night periods in a typical medium-income neighborhood from December 19, 1989 through February 5, 1990.

The results show that the main contributors to suspended particles are vehicles without catalytic converters and heavy-duty diesel vehicles. The contribution of refineries, smelters, cement plants, resuspended dust, natural sources, and secondary aerosols were taken into account. In particular, the vehicles without catalytic converters represent the major contribution to PM2.5. They contribute with 50% during the day and 38% at night. Most of the source profiles were taken from the model library SPECIATE EPA. However, native profiles for soil, vehicles, and refinery were designed.     

Chemical composition of fugitive dust emitters in Mexico City

The gravimetric and chemical composition of fugitive dust emitters of Mexico City were analyzed to determine the particulate matter source profiles. Samples of geological material, unpaved and paved roads, agricultural soil, dried lake, asphalt, cement plants, landfill, gravel, and tezontle soil, were collected directly from the ground using a broom and a dustpan. These were dried, sieved and taken through a laboratory resuspension chamber to emulate the natural wind-blown processes of bulk soils and also to provide a uniform deposit on Teflon membrane and quartz fiber filters for further gravimetric and chemical analyses of PM_2.5 and PM₁₀ size fractions. Chemical analyses of the filters included X-ray fluorescence for elemental composition, ion chromatography for water soluble anions, atomic absorption for water soluble metals, automated colorimetric analysis for ammonium and thermal/optical reflectance analysis for carbon species. The data show that most fugitive emitters are composed of 20–30% PM_2.5, which is relatively less than the reported contribution by fossil fuels and biomass (40–60%).     

Time-series analysis of above-road particulate matter at the Caldecott Tunnel exit

On November 18, 1997, above-road particulate matter (PM) lidar (light detection and ranging) signals and heavy-duty (HD) and light-duty (LD) vehicle counts were simultaneously collected for 894 10-sec sampling periods at the Caldecott Tunnel in Orinda, CA, for the purpose of measuring the relative contributions of LD and HD vehicles to the PM lidar signal under real-world driving conditions. The relationship between the PM lidar signal and traffic activity (i.e., LD and HD traffic volumes) was examined using a time-series analysis technique, multilagged regression. The time-series model results indicate that the PM lidar signal in the current sampling period (PMt) depended on the level recorded in the previous three sampling periods (i.e., PMt-1, PMt-2, and PMt-3), the number of LD vehicles in the seventh past sampling period (LDt-7), and the number of HD vehicles measured 80 sec previous to the current sampling period (HDt-8). On a 10-sec period basis, the model results indicate that HD vehicles contributed, on average, 3 times more to above-road PM lidar signals than did LD vehicles. The observed lag in the relationship between vehicle types and the lidar signal 20 m above the road suggests that resuspended road dust, rather than tailpipe exhaust emissions, was the main source of the detected PM. Detection of road dust at such heights above the road suggests the need for investigating the processes governing the vertical transport and recycling of PM over the road as a function of vehicle dynamics under a range of meteorological conditions.     

Oxygenates in Exhaust from Simple Hydrocarbon Fuels

Photochemical air pollution is known to be caused largely by automotive emissions such as hydrocarbons and oxygenated hydrocarbon derivatives. Unlike the hydrocarbons, the contribution of the oxygenates has been virtually unexplored, mainly because of lack of appropriate analytical methods. The objective of this study was to identify and estimate the levels of oxygenated hydrocarbon derivatives in exhaust from simple hydrocarbon fuels. This information is expected to yield ultimately estimates of the relative levels of various classes of oxygenates in exhaust from full-boiling-range gasolines. Identification and measurement of oxygenates in exhaust from the simplified fuels were accomplished using gas chromatography in conjunction with time-of-flight mass spectrometry. The analytical procedure involved concentration of the exhaust organics, followed by a two-stage chromatographic separation of the resultant mixture of oxygenates and hydrocarbons. Identified oxygenates in exhaust from nine test fuels included saturated and unsaturated aldehydes, ketones, and alcohols, as well as ethers, esters, and nitroalkanes; analytical data on organic acids were inconclusive. Of the identified noncarbonyl oxygenates, phenols, cyclic ethers and nitromethane appear to be relatively the most abundant.     

Source apportionment of PM10 in six cities of northern China

Ambient PM₁₀ was sampled in six northern China cities (Urumqi, Yinchuan, Taiyuan, Anyang, Tianjin and Jinan) from December 1999 to July 2002, and analyzed for 16 chemical elements, two water-soluble ions, total carbon, and organic carbon. In addition, chemical source profiles consisting of the same particulate components were obtained from a number of naturally occurring geological sources (soil dust from exposed lands) and sources of atmospheric particulates resulting from human activities (resuspended dust, cement, coal combustion fly ash, vehicle exhaust, and secondary particles). Ambient and source data were used in a chemical mass balance (CMB) receptor model to determine the major source of PM₁₀ in these six cities. Results of CMB modeling showed that the major source of ambient PM₁₀ in all the cities was resuspended dust. Significant contributions from coal fly ash were also found in all six cities.     

The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes

The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.     

Antioxidants in Capsicum chinense: Variation among countries of origin

The main objective of this investigation was to evaluate fruits of C. chinense accessions for their concentration of β -carotene, ascorbic acid, and phenols for use as parents in breeding for these phytochemicals. Mature fruits of 63 accessions of C. chinense originally acquired from Belize, Brazil, Colombia, Ecuador, Mexico, Peru, Puerto Rico, and the United States were analyzed for their chemical composition. Fruits of C. chinense accessions PI-152452 (Brazil) and PI-360726 (Ecuador) contained the greatest concentrations of ascorbic acid (1.2 and 1.1 mg g^?1 fresh fruit, respectively), while PI-438648 (Mexico) contained the greatest concentration of total phenols content (349 μ g g^?1 fresh fruit) among the other 63 accessions tested. Accession PI-355817 from Ecuador contained the greatest concentrations of β -carotene (8 mg g^?1fresh fruit). These accessions were identified as potential candidates for mass production of antioxidants with health-promoting properties.     

Extractable organic matter of Standard Reference Material 1649a influences immunological response induced by pathogen-associated molecular patterns

Background, aim, and scope  

Lungs are permanently and simultaneously challenged by airborne microorganisms and airborne pollutants. Temporal increase of airborne particulate matter (APM), a potential carrier for extractable organic matter (EOM), degrades the situation of pulmonary patients. The Ah receptor (AhR) has been described as an important factor influencing the immunological challenge by viral infections. Molecular mechanisms underlying epidemiological observations are not well understood. Cytokine secretion (IL-6, IL-8, and TGF-β) from human bronchial epithelial cells (Beas2B) was determined as an indicator for immune responses upon co-stimulation with an artificial analog of viral dsRNA [polyinosinic/polycytidylic acid, (PIC)] and EOM of Standard Reference Material 1649a (SRM). Since polycyclic aromatic hydrocarbons are major components of APM usually acting via the AhR, particular focus was on AhR involvement.     

Time-Series Analysis of Above-Road Particulate Matter at the Caldecott Tunnel Exit

ABSTRACT

On November 18, 1997, above-road particulate matter (PM) lidar (light detection and ranging) signals and heavy-duty (HD) and light-duty (LD) vehicle counts were simultaneously collected for 894 10-sec sampling periods at the Caldecott Tunnel in Orinda, CA, for the purpose of measuring the relative contributions of LD and HD vehicles to the PM lidar signal under real-world driving conditions. The relationship between the PM lidar signal and traffic activity (i.e., LD and HD traffic volumes) was examined using a time-series analysis technique, multilagged regression. The time-series model results indicate that the PM lidar signal in the current sampling period (PM_t) depended on the level recorded in the previous three sampling periods (i.e., PM_t-1, PM_t-2, and PM_t-3), the number of LD vehicles in the seventh past sampling period (LD_t-7), and the number of HD vehicles measured 80 sec previous to the current sampling period (HD_t-8). On a 10-sec period basis, the model results indicate that HD vehicles contributed, on average, 3 times more to above-road PM li-dar signals than did LD vehicles. The observed lag in the relationship between vehicle types and the lidar signal 20 m above the road suggests that resuspended road dust, rather than tailpipe exhaust emissions, was the main source of the detected PM. Detection of road dust at such heights above the road suggests the need for investigating the processes governing the vertical transport and recycling of PM over the road as a function of vehicle dynamics under a range of meteorological conditions.     

Emission rates and comparative chemical composition from selected in-use diesel and gasoline-fueled vehicles

Emission samples for toxicity testing and detailed chemical characterization were collected from a variety of gasoline- and diesel-fueled in-use vehicles operated on the Unified Driving Cycle on a chassis dynamometer. Gasoline vehicles included normal particle mass (particulate matter [PM]) emitters (tested at 72 and 30 degrees F), "black" and "white" smokers, and a new-technology vehicle (tested at 72 degrees F). Diesel vehicles included current-technology vehicles (tested at 72 and 30 degrees F) and a high PM emitter. Total PM emission rates ranged from below 3 mg/mi up to more than 700 mg/mi for the white smoker gasoline vehicle. Emission rates of organic and elemental carbon (OC/EC), elements (metals and associated analytes), ions, and a variety of particulate and semi-volatile organic compounds (polycyclic aromatic hydrocarbons [PAH], nitro-PAH, oxy-PAH, hopanes, and steranes) are reported for these vehicles. Speciated organic analysis also was conducted on the fuels and lube oils obtained from these vehicles after the emissions testing. The compositions of emissions were highly dependent on the fuel type (gasoline vs. diesel), the state of vehicle maintenance (low, average, or high emitters; white or black smokers), and ambient conditions (i.e., temperature) of the vehicles. Fuel and oil analyses from these vehicles showed that oil served as a repository for combustion byproducts (e.g., PAH), and oil-burning gasoline vehicles emitted PAH in higher concentrations than did other vehicles. These PAH emissions matched the PAH compositions observed in oil.     

Schedule of Technical Sessions

Peroxyacyl nitrates are a family of compounds which result from photochemical reactions between contaminants released to the atmosphere by combustion of organic fuels. Peroxyacetyl nitrate (PAN) is the most abundant member of this family and is responsible for serious plant injury in some polluted areas. Plant injury has been recognized in at least 19 states and several foreign countries but economic loss has caused greatest concern in California. Characteristically, injury from PAN appears as glazing or bronzing of the lower leaf surface but the symptom syndrome may also include tissue collapse, chlorosis, and leaf drop. PAN inhibits activity of several enzyme systems by attacking the sulfhydryl group when enzyme extracts are fumigated in vitro, PAN may produce visible symptoms when sensitive plants are exposed for 4 hours to about 14 ppb. Other chemical members of the family are more toxic than PAN. Concentrations of 20 to 30 ppb PAN occur frequently at Riverside, Calif, and a maximum peak of 58 ppb was measured for one 2-hour period. Peaks as high as 54 ppb were reported at Salt Lake City, and 210 ppb at Los Angeles, Calif.     

Dilution-based emissions sampling from stationary sources: Part 1--Compact sampler methodology and performance

This paper presents the design and performance of a compact dilution sampler (CDS) for characterizing fine particle emissions from stationary sources. The sampler is described, along with the methodology adopted for its use. Dilution sampling has a number of advantages, including source emissions that are measured under conditions simulating stack gas entry and mixing in the ambient atmosphere. This is particularly important for characterizing the semivolatile species in effluents as a part of particulate emissions. The CDS characteristics and performance are given, along with sampling methodology. The CDS was compared with a reference dilution sampler. The results indicate that the two designs are comparable for tests on gas-fired units and a diesel electrical generator. The performance data indicate that lower detection limits can be achieved relative to current regulatory methods for particulate emissions. Test data for the fine particulate matter (PM2.5) emissions are provided for comparison with U.S. Environment Protection Agency (EPA) Conditional Test Method 040 for filterable particulate matter (FPM) and the EPA Method 202 for condensable particulate matter. This comparison showed important differences between methods, depending on whether a comparison is done between in situ FPM determinations or the sum of such values with condensable PM from liquid filled impingers chilled in an ice bath. These differences are interpretable in the light of semivolatile material present in the stack effluent and, in some cases, differences in detection and quantification limits. Determination of emissions from combustors using liquid fuels can be readily achieved using 1-hr sampling with the CDS. Emissions from gasfired combustors are very low, requiring careful attention to sample volumes. Sampling volumes corresponding with 6-hr operation were used for the combined mass and broad chemical speciation. Particular attention to dilution sampler operation with clean dilution air also is essential for gas-fired sources.