Grantee Research Project Results
2001 Progress Report: Relationship Between PM2.5 Semi-volatile Organic Material, Other PM2.5 Components and Heart Rate Variability in The Elderly
EPA Grant Number: R827993Title: Relationship Between PM2.5 Semi-volatile Organic Material, Other PM2.5 Components and Heart Rate Variability in The Elderly
Investigators: Eatough, Delbert J. , Pope, Clive Arden
Institution: Brigham Young University
EPA Project Officer: Chung, Serena
Project Period: February 1, 2000 through January 31, 2003
Project Period Covered by this Report: February 1, 2001 through January 31, 2002
Project Amount: $797,013
RFA: Airborne Particulate Matter Health Effects (1999) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air , Human Health
Objective:
The overall objective of this research project is to evaluate factors which influence the effect of fine particulate matter (PM) on human health using continuous measurement of PM2.5 mass, including the semi-volatile components. Included in this research project is an evaluation of the effect of changes in exposure on heart rate variability (HRV) and markers of blood inflammation in elderly subjects. Ammonium nitrate and semi-volatile organic material (SMV) are significant components of fine particulate material in most urban atmospheres, which are not properly identified during sampling with conventional systems because of the loss of these species from the collected particles during sampling. Techniques, such as the beta gauge and the Tapered Element Oscillating Microscale (TEOM) monitor, which attempt to make continuous measurements of PM2.5 mass, must heat the sample to remove the particle-bound water and evaporate much of the semi-volatile PM2.5. Because of this problem of removing particle-bound water, without loss of semi-volatile PM2.5, there is currently no accepted method for continuous measurement of the mass of total PM2.5 suspended in the atmosphere.
The specific objectives of this research project are to: (1) evaluate the usefulness of the newly developed, Real-time total Ambient Mass Sampler (RAMS) for total (nonvolatile plus semi-volatile) PM2.5 mass, particularly the time and health relevance of this method, as compared to other measurements of PM2.5 parameters; (2) intercompare a variety of batch (24-hour) and continuous (1-hour) PM2.5 measurement methods, including equilibrated mass (FRM), nonvolatile mass TEOM, total mass (RAMS, the new method), particulate carbon (R and P monitor), soot (Anderson Aethalometer), and particle number; (3) determine the health-relevance of the various PM2.5 measurements by correlation with health measures; (4) identify, where possible, PM2.5 components associated with the exacerbation of cardiovascular health problems; and (5) identify monitoring paradigms which optimize health- and time-relevant monitoring strategies for PM2.5. The sum of the 24-hourly mass measurements also are being compared to mass measured by the 24-hour filter collections and the Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) results.
Progress Summary:
Objectives 1 and 2 have been completed, and considerable progress has been made on Objective 3 in the current reporting period.
Study Sites
Salt Lake City. The Salt Lake City site was developed. The monitoring site is located immediately adjacent to the State of Utah Air Quality Monitoring site at the Hawthorne Elementary School in Salt Lake City, UT. The site is in a residential area about 4 km southeast of the central business district. The population in Salt Lake Valley is about 3/4 million. PM2.5 pollution at the site is dominated by primary emissions and secondary products from mobile source emissions, and during the winter, wood smoke from home combustion. During the summer of 2000, the site also was impacted by emissions from forest fires in the Wasatch Mountains to the east of Salt Lake City. There are no major point sources which make a significant impact at the Hawthorne site. Data have been collected at the site since December 1999. The following PM2.5 sampling methods have been used at the Salt Lake City site.
Bountiful Site. The Bountiful monitoring site is located immediately adjacent to the Air Quality Monitoring site at the Bountiful Fire Station in downtown Bountiful, UT. The Bountiful site is 25 km north of the Hawthorne site and is sheltered from direct transport of pollutants from the Hawthorne site by a range of mountains which extend from the main Wasatch Mountains out into the valley between the two sites. The population in the Bountiful area is about 100,000. The region has no major business center such as Salt Lake, but is a major commuter traffic feed to the Salt Lake area. Immediately to the west of Bountiful are a series of oil refineries. Bountiful is impacted by mobile source emissions, wood smoke emissions, and emissions from these refineries during transport from the west (Long, 2002b).
Lindon Site. The Lindon monitoring site is located immediately adjacent to the State of Utah Air Quality Monitoring site at the Lindon Elementary School. The Lindon site is 60 km south of the Hawthorne site and also is sheltered from direct transport of pollutants from the Hawthorne site by a range of mountains, which extend from the main Wasatch Mountains out into the valley between the two sites. The population near the Lindon area includes Provo and Orem, with a combined population of about 300,000. The Lindon region has no major business center but is a major commuter traffic feed to the Provo area. Immediately to the west of Lindon is an integrated steel mill. The site is located such that impacts from the steel mill are expected. Lindon is impacted by mobile source emissions, wood smoke emissions, and emissions from the integrated steel mill, including blast furnace and coke oven emissions.
The samplers used at both the Lindon and Boutiful sites are described below. Samplers at the two sites included the RAMS, TEOM, Aethalometer, CNC Counter, and PC-BOSS.
Continuous Sampling Methods
RAMS. The RAMS, based on diffusion denuder, Nafion dryer, and TEOM monitor technology, is a state-of-the-art sampler being used for the real-time determination of total PM2.5 mass, including semi-volatile species (Eatough, 1999, 2000ab; Modey, 2002). The RAMS measures total PM2.5 mass with a TEOM monitor using a "sandwich" filter to retain SVM, which would be lost from particles in a conventional TEOM monitor. The sandwich filter consists of a Teflon-coated particle collection filter (R and P TX40), followed by a recently developed charcoal-impregnated cellulose fiber filter (CIF) (Schleicher and Schuell) to collect any SMV compounds lost from the particles during sampling. Care must be taken to remove from the sample stream all gas phase species that can be absorbed by the CIG filter to prevent over determination of PM2.5 mass.
The RAMS has a dual inlet system consisting of a 2.5 µm cut-point cyclone inlet followed by a particle concentrator. A BOSS diffusion denuder, packed with fifteen, 25-cm long, parallel CIF strips, serves to remove gas phase organic and other species. Gas-phase species such as NO2 and O3 are removed by a series of triethanolamine coated multi-annular denuders. Gas-phase water is removed by a series of two, one-foot long, 200 element Nafion Dryers, located before and after the BOSS and annular denuders. To correct for any gas phase species not removed by the denuders and dryers, but absorbed by the sandwich filter, a second similar system is employed. A quartz filter is placed immediately after the first Nafion Dryer on the second system to remove all particles. The second system is then used as a blank to correct the data obtained with the RAMS. Total PM2.5 data have been collected over a 2-year period on a 1-hour basis with the RAMS. These data have been compared with the 1-hour averaged non-volatile PM2.5 data obtained with the TEOM monitor (Long, 2002a; Long, 2001; Long, 2000). One-hour RAMS data also have been averaged over 4-, 6-, and 24- hour periods for comparison with mass data obtained from the PC-BOSS and other samplers (Long, 2002a; Long, 2002c; Long, 2001; Long, 2000).
R and P TEOM Monitor. The TEOM Monitor is a microbalance that determines mass continuously on a heated filter. Semi-volatile PM will evaporate at the standard operating temperature of the instrument (50°C, which is required to remove particle-bound water). This technique measures only non-volatile PM2.5. One-hour-averaged, non-volatile PM2.5 mass concentrations have been determined over a 2-year period using an R and P TEOM monitor operating under normal conditions.
TSI CPC Monitor. A TSI monitor for the determination of condensation nuclei and their size distribution was used to determine total fine particle number. Total particle number will be dominated by ultra-fine particles (<100 nm). This instrument is a real-time monitor, therefore, data have been averaged over 1-hour periods throughout the 2-year sampling program.
R and P Series 5,400 Ambient Carbon Particulate Monitor. The Series 5,400 Ambient Carbon Particulate Monitor from Rupprecht and Patashnick was used to characterize the carbon content of suspended particles on a continuous basis. The Series 5400 performs a thermal-CO2 analysis to determine the amount of organic and elemental carbon (soot) present in a collected sample. During the analysis phase, the collected sample is first heated to 375°C, and then to 750°C to determine the concentrations of "organic" and "elemental carbon," respectively. One hour carbon concentration averages were obtained over the first year, enabling comparison with the 1- hour averaged TEOM and RAMS data.
Anderson Aethalometer. An Anderson Instruments Inc. (Model RTAA-900) Aethalometer is used for the determination of aerosol elemental carbon (soot) on a continuous basis. One-hour average elemental-carbon (soot) concentrations have been obtained and compared with the 1-hour averaged TEOM and RAMS data (Long, 2002b).
Chemical Composition Samplers
PC-BOSS. The combination of technology used in the high-volume (BIG) BOSS and the Harvard particle concentrator has resulted in the PC-BOSS, a state-of-the-art sampler used to determine particulate composition (Lewtas, 2001; Long, 2002a; Long, 2002b; Long, 2002c).
The PC-BOSS has been used during the summer and winter period health studies for sample collection to determine fine particulate mass, trace elements, sulfate, acidity, carbonaceous material (elemental and organic), nitrate, SVM, and semi-volatile nitrate. Samples for the chemical characterization of PM2.5 in the minor flow following a particle concentrator and a BOSS diffusion denuder were collected in a filter pack containing a pre-fired 47 mm quartz filter (Pallflex), followed by a newly developed CIG to determine fine particulate carbonaceous material and nitrate, including semi-volatile species lost from the particles during sampling. A second parallel filter pack containing a 47 mm Teflon (Whatman) filter followed by a 47 mm Nylon (Gelman, Nylasorb) filter was used to determine PM2.5 mass, sulfate, and nitrate, including any nitrate lost from the particles during sample collection. In addition to the daily 24-hour sample collection, intensive studies have been performed during week-long winter episodes (Long, 2002c). During non-episode periods, 24-hour samples have been collected each day for comparison with equilibrated PM2.5 mass concentrations measured on a 24-hour basis by the PM2.5 FRM (Long, 2002a; Long, 2002b; Long, 2002c).
PM2.5 FRM. The FRM is the method used to determine fine particulate mass in the atmosphere. The FRM collects particles on a single filter in a temperature controlled environment. Collected mass is determined gravimetrically. The FRM data have been obtained by the State of Utah Division of Air Quality.
RAMS Validation Results
Comparison of RAMS and PC-BOSS Results. The results obtained by the RAMS for the continuous determination of PM2.5 mass, including SVM, were averaged (24-hour) over the periods where PC-BOSS data were obtained. These results were validated by comparison with results obtained from the PC-BOSS sampler over the same time period (Long, 2002; Long, 2002a; Long, 2002b; Long, 2002c; Long, 2001; Long, 2000). Integrated PC-BOSS samples were used to determine the mass of PM2.5 retained on a filter and total PM2.5 mass, including semi-volatile nitrate and organic material lost from the filter during sampling. PC-BOSS sulfate and nitrate were present as ammonium sulfate and ammonium nitrate, respectively. Fine particulate organic material was taken to be 61 percent carbon. Crustal material was estimated from proton induced x-ray analysis (PIXE) results. Constructed mass was obtained for each PC-BOSS sample as the sum of estimated crustal material, ammonium sulfate obtained from the Teflon filters, the ammonium nitrate from the Teflon filters, the volatile ammonium nitrate from the Nylon filters, the soot collected on the quartz filters, and the total organic carbonaceous material, which is the sum of the organic material on the quartz filter and the SVM lost from the particles during sampling but collected on the CIF.
For all samples, the linear regression of RAMS measured versus PC-BOSS constructed PM2.5 mass results, gives r2 = 0.99, a slope of 0.98 ± 0.05, and a of ±10 percent or ±1.5 µg/m3. Results obtained with the RAMS and the PC-BOSS show that PM2.5 mass, including semi-volatile species, were continuously and accurately monitored at the sampling sites in Salt Lake City, Bountiful, and Lindon with the RAMS (Long, 2002a; Long, 2002b; Long, 2002c; Long, 2000).
Results Obtained With the Continuous Samplers
Comparison of RAMS and TEOM Monitor Results. The results obtained in the study are illustrated by 1-hour average RAMS and TEOM monitor results obtained during a 10-day period in the winter of 2000-2001 in Bountiful and Hawthorne given in Figures 1A and B, respectively, and for a 14-day period at Hawthorne during the summer of 2000, when the site was impacted by emissions from forest fires (see Figure 1C) (Long, 2002b). As indicated in Figure 1, both for the time periods when an inversion or the forest fire emissions were present and the days when a frontal passage resulted in substantially lower PM concentrations, the RAMS PM2.5 mass measurements are generally equal to or greater than the TEOM PM2.5 mass measurements. The fraction of PM2.5 not measured by the TEOM averaged 35 percent over these time periods. The higher RAMS PM2.5 mass, compared to that of the TEOM monitor, can be attributed to the presence of semi-volatile PM2.5, which is measured by the RAMS but not by the TEOM. This additional mass is secondary particulate material formed from nitrogen oxides and organic compounds in the atmosphere (Long, 2002a; Long, 2002b).
Comparison of RAMS and FRM Results. The PM2.5 FRM sampler has lower losses than the TEOM (Long, 2002a; Long, 2002b). The fraction of PM2.5 not measured by the FRM is low in the winter and high in the summer, and has averaged 16 percent over the study period (Long, 2002a).
1-Hour Average PM2.5 Source Apportionment. Source apportionment analyses are being done to support the interpretation of the health data (Long, 2002b). Source apportionment has been previously reported for PM2.5 data during a 10-day winter period with high PM2.5 concentrations due to winter inversions, and during a 14-day summer period, when the site was impacted by smoke from wildfires in the Wasatch Mountains (Long, 2002b), (see Figure 1). In both cases, substantial amounts of SVM were present, and were not measured by a TEOM monitor but detected by RAMS. The PM2.5 data have been combined with concentrations of particulate soot and soil corrected potassium, and with gas phase concentrations of NOx, CO, and SO2 to apportion the PM2.5 to primary emissions emitted by, and secondary particulate material formed from, emissions from mobile sources, oil refineries, and wood smoke combustion (including the forest fire emissions) on an hourly basis. Wood smoke and mobile source primary emissions dominated the contribution to the non-volatile fraction of the PM2.5, with about equal
Figure 1. One-Hour Average RAMS (total PM2.5) and TEOM Monitor (Non-Volatile PM2.5) Results During December 28, 2000, Through January 5, 2001. Results for the Bountiful (A), Hawthorne (B) sampling sites, and at Hawthorne from July 23, 2000 through August 5, 2000, the summer at Hawthorne (C). The difference between the two measurements is SVM lost from the heated (50°C) filter of the TEOM (from Long, 2002a).
Figure 2. Apportionment of PM2.5 to Primary Emissions From Wood Smoke and Mobile Sources at the Hawthorne Site From December 28, 2001, Through January 6, 2001. The variation in SVM, which is a secondary atmospheric product and therefore shows a different time pattern than the apportioned primary emissions (Long, 2002b).
contributions for each, but very different diurnal patterns for the two contributions. This is illustrated by the apportion data for Hawthorne given in Figure 2 (Long, 2002b). The diurnal patterns for the attribution were consistent with the emission patterns for these two sources. The SVM could not be directly attributed to any source but appeared to be secondary ammonium nitrate and organic material formed from gaseous emissions of NOx, and gas phase organic compounds from both mobile sources and wood smoke. This analysis effort currently is being extended to include all time periods when human exposure data were obtained.
Heart Rate Variability, Blood Inflammation, and PM2.5. Our study involves examining the effects of particulate air pollution on cardiopulmonary health. These studies have included the evaluation of the association of daily measures of weather and particulate air pollution with day-to-day changes in 1-hour averaged heart rate HR, HRV, and markers of blood inflammation. The study has been conducted using panels of retired adults living close to the monitoring site.
Many previous studies have found associations between episodes of air pollution and increases in cardiovascular hospitalizations and deaths. However, there has been limited information about the mechanisms behind these associations. Several recent studies, including studies conducted in UT, have suggested that particulate air pollution can change cardiac autonomic function (i.e., lower the human heart's ability to vary its speed), resulting in increased serious cardiac events.
During the health studies, a Holter monitor was worn for various 24-hour periods to provide continuous monitoring of HR and other key measures, while going about daily activities. Multiple data sets during periods of low, moderate, and high pollution were obtained. At the end of each monitoring session, blood was drawn to assess various markers of inflammation.
Health effects data are available for panels of 20 to 30 individuals for each of the two winter and one of the summer time periods, in which health effects data were obtained. These data include several 24-hour time periods for each participant, in which the PM2.5 concentrations were low, moderate, and high. All exposure data for the study panels were determined from the fixed site monitoring stations at the three study locations. To minimize any possible effects of spatial variations in ambient pollution, panel participants who lived within 4 blocks of each fixed site monitor were selected. However, no personal exposure data were obtained because experimental techniques for the facial determination of the wide range of PM2.5 components measured currently are not available. Therefore, it is a postulate of the study that the data from the fixed site will be representative of the indoor exposure of each of the panel participants to outdoor generated pollutants. Participants were chosen so that indoor combustion sources were not present in the home and the type of home ventilation at each site was comparable, insofar as was possible. The study participants were elderly, healthy, retired couples, and two people were studied in each home.
The initial postulate of the study was that hourly measurements of PM2.5 components would be more health relevant than 24-hour averaged data. This postulate assumes that reasonably rapid responses will be seen in changes and increases in HRV markers of blood inflammation following a peak exposure to PM2.5. During the course of the 2-year ambient sampling and health effects study, three small pilot studies were conducted to investigate whether this was a reasonable postulate. These each involved the study of short-term changes in HRV and the markers of blood inflammation in subjects exposed to PM2.5 in a controlled indoor setting. The test aerosol for each of these studies was environmental tobacco smoke. The first study was conducted at the Salt Lake City International Airport (Pope 2001), and the last two studies were conducted in smoking and nonsmoking rooms of a local motel (Pope, et al., 2002 and Pope, et al., analysis in progress). The results of these three studies all indicate that changes in both HRV and makers of blood inflammation are seen within a few hours of exposure. Furthermore, the studies indicated that recovery from these effects also occurs within a few hours after the exposure. The rate of recovery may be related to the magnitude of the exposure. Thus, these studies support the hypothesis upon which the ongoing analysis of the ambient and health data is based.
Future Activities:
Completion of the Field Sampling Effort. The field sampling and associated health effects measurement efforts will be completed this summer. Particular emphasis will be placed on obtaining data at the Lindon site this summer. Included in the research plans for this final field sampling program will be a comparison of real-time measurements of PM2.5 mass and PM2.5 components. These data will aid in the interpretation of the combined ambient health data for the entire study in support of goal (2) given in the summary (see Section I). Real-time measurement of nitrate, sulfate, and oxidants will be made in cooperation with Dr. P. Dasgupta, Texas A&M University. These measurements, coupled with the measurements being taken during the research, will allow for the real-time calculation of PM2.5 mass from real-time components measurements.
Statistical Analysis of the PM2.5 and Health Data. The data collected will allow the evaluation of evidence of changes in the heart's ability to respond to changes in activity, stress, or other factors. This will include looking for evidence of changes in blood measures, such as inflammation and various other blood related factors that can effect the heart. Also, the monitoring of various constituents (including the source apportionment results) of the air pollution, will allow for an evaluation of the components of air pollution that may be most important in terms of impacts on human health. Analysis and interpretation of the 1-hour average HRV and 24-hour blood inflammation data as compared to the 1-hour and 24-hour PM2.5 concentration, composition, and apportioned source results are underway. As illustrated in Figures 1 and 2, the diurnal patterns for each of these PM2.5 constituents is quite different. This may make possible the elucidation of which PM components included in the analyses are more related to the observed variations in HRV. Completion of this analysis effort will be a major task for the third year.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
Other project views: | All 27 publications | 15 publications in selected types | All 15 journal articles |
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Lewtas J, Pang P, Booth D, Reimer S, Eatough DJ, Gundel LA. Comparison of sampling methods for semi-volatile organic carbon associated with PM2.5. Aerosol Science and Technology 2001;34(1):9-22. |
R827993 (2001) R825367 (Final) |
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Modey WK, Pang Y, Eatough NL, Eatough DJ. Fine particulate (PM2.5) composition in Atlanta, USA: assessment of the particle concentrator-Brigham Young University organic sampling system, PC-BOSS, during the EPA supersite study. Atmospheric Environment 2001;35(36):6493-6502. |
R827993 (2000) R827993 (2001) R827993 (2003) R827993 (Final) |
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Eatough DJ, Eatough NL, Obeidi F, Pang Y, Modey W, Long R. Continuous determination of PM2.5 mass, including semi-volatile species. Aerosol Science and Technology 2001;34(1):1-8. |
R827993 (2000) R827993 (2001) R827993 (Final) R825367 (Final) |
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Long RW, Smith R, Smith S, Eatough NL, Mangelson NF, Eatough DJ, Pope CA, Wilson WE. Sources of fine particulate material along the Wasatch Front. Energy & Fuels 2002;16(2):282-293. |
R827993 (2000) R827993 (2001) R827993 (2003) R827993 (Final) |
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Long RW, Eatough NL, Mangelson NF, Thompson W, Fiet K, Smith S, Smith R, Eatough DJ, Pope CA, Wilson WE. The measurement of PM2.5, including semi-volatile components, in the EMPACT program:results from the Salt Lake City Study. Atmospheric Environment 2003;37(31):4407-4417. |
R827993 (2001) R827993 (2003) R827993 (Final) |
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Supplemental Keywords:
PM2.5, semi-volatile organic material, SVM, health effects, heart rate variability, HRV, blood inflammation., RFA, Scientific Discipline, Health, PHYSICAL ASPECTS, Air, particulate matter, Health Risk Assessment, air toxics, Susceptibility/Sensitive Population/Genetic Susceptibility, Risk Assessments, Biochemistry, Environmental Monitoring, Physical Processes, tropospheric ozone, genetic susceptability, ambient air quality, elderly adults, sensitive populations, cardiopulmonary responses, fine particles, human health effects, PM 2.5, semi-volatile organic material, stratospheric ozone, health risks, cardiovascular vulnerability, heart rate variability, ambient air, exposure, air pollution, chemical mixtures, chronic health effects, particulate exposure, human exposure, cardiopulmonary response, blood pressure, environmentally caused disease, highrisk groups, human susceptibility, mortality, Federal Reference Method, age dependent response, atmospheric chemistry, cardiac arrhythmias, transition metals, air quality, environmental hazard exposures, toxicsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.