2000 Progress Report: Exposure Characterization Error

EPA Grant Number: R827351C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R827351
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EPA NYU PM Center: Health Risks of PM Components
Center Director: N/A
Title: Exposure Characterization Error
Investigators: Ito, Kazuhiko
Institution: New York University School of Medicine
EPA Project Officer: Chung, Serena
Project Period: June 1, 1999 through May 31, 2005 (Extended to May 31, 2006)
Project Period Covered by this Report: June 1, 2000 through May 31, 2001
RFA: Airborne Particulate Matter (PM) Centers (1999) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Particulate Matter , Air


The objectives of this project are threefold: (1) to quantitatively characterize spatio-temporal error of particulate matter (PM) components and gaseous co-pollutants measured at routine regulatory-based air monitors as a function of site characteristics using the entire U.S. air monitoring network; (2) to establish the relationship between the estimated error at a given monitoring site and the effect of size/significance in mortality and morbidity models; and (3) to evaluate the relative contribution of the error due to site-to-site and person-to-site variability. This project will test the prevailing hypothesis that PM and gaseous co-pollutant data from a single air monitoring station can adequately reflect the population exposure for the entire city, and that resulting risk estimates and their significance are not biased.

Progress Summary:

In the first year of this project, we processed much of the nationwide air pollution and mortality records. In the first half of the second year, we extended our study period from 10 years to 13 years because we could obtain mortality records for three additional years (1995-1997) than the originally planned period (1985-1994). The daily PM10 data, hourly ozone (O3), sulfer dioxide (SO2), and carbon monoxide (CO) data for all the sites in the contiguous U.S. for the 13-year study period have been retrieved and processed. For the gaseous pollutants, daily 24-hour averages were computed for all the sites. There were 2,368 sites for PM10, 1,544 sites for O3, 1,473 sites for SO2, and 904 sites for CO for the entire study period. Although PM10 had the largest number of sites, a smaller number of sites had a large number of available days because of the every-6th-day sampling schedule used at most sites. However, 25 percent of the PM10 sites (590 sites) had at least 565 days available (enough daily data to conduct time-series study with a reasonable statistical power), and 10 percent (236 sites) had over 900 days of observations available. As the gaseous pollutants (i.e., O3, SO2, and CO) were collected on a daily basis, larger numbers of daily observations were available. For example, 25 percent of O3 (386 sites), SO2 (368 sites), and CO (226 sites) had at least 3,100 days of observations. Data analysis has started for PM10 and gaseous pollutants in some of the larger cities (e.g. Detriot, Chicago). Preliminary results suggest that monitors with low correlation tend to have lower mortality relative risks in some of these cities.

We decided to further extend the study period, because many ambient monitors started collecting PM2.5 data in 1999. Nationwide PM2.5 data for the period 1999-2000 have been retrieved and processed. While the collection period for much of the PM2.5 data is shorter than that for PM10, many of these PM2.5 monitors collected data every-3rd-day (as compared to every-6th-day for most of the PM10 data), or even every day, providing the sample size sufficient to conduct data analyses for the first objective above, and even for the second objective above for the cities with large population size. Thus, taking advantage of the newly available PM2.5 data, while delaying the original schedule set for the more limited PM10 and PM2.5 data, would greatly enhance the overall research goal, adding a more powerful comparison of the PM10 and PM2.5 data.

Future Activities:

Air pollution data analyses for the extended study period (1985-2000) will be continued. As originally planned, characterization of air pollution data (e.g., monitor-to-monitor temporal correlation) will be conducted for the nationwide data. However, more detailed characterization and comparison of the PM2.5 and PM10 data will be conducted in areas where extensive data for both of these PM indices exist from multiple monitors. Mortality and morbidity (the elderly hospital admission) data analyses will be conducted in these areas up to 1999 (2000 for the elderly hospital admission data). Finally, since an ongoing Environmental Protection Agency (EPA)-funded New York University (NYU) PM Center personal exposure study (Lippmann) has finished collecting data in New York City, we will be able to compare the magnitude of the error associated with person-to-monitor differences and monitor-to-monitor variability.

Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other subproject views: All 7 publications 7 publications in selected types All 7 journal articles
Other center views: All 111 publications 100 publications in selected types All 88 journal articles
Type Citation Sub Project Document Sources
Journal Article Ito K, Thurston GD, Nadas A, Lippmann M. Monitor-to-monitor temporal correlation of air pollution and weather variables in the North-Central U.S. Journal of Exposure Analysis & Environmental Epidemiology 2001;11(1):21-32. R827351 (Final)
R827351C001 (2000)
R827351C001 (2002)
R827351C001 (2003)
R827351C001 (Final)
R825271 (Final)
  • Abstract from PubMed
  • Full-text: JESEE-Full Text PDF
  • Abstract: JESEE-Abstract
  • Supplemental Keywords:

    particulate matter, PM, exposure, clinical, toxicology, spatio-temporal, error, air monitor, mortality., RFA, Health, PHYSICAL ASPECTS, Scientific Discipline, Air, ENVIRONMENTAL MANAGEMENT, particulate matter, Environmental Chemistry, Health Risk Assessment, Risk Assessments, Physical Processes, Environmental Monitoring, Atmospheric Sciences, Atmosphere, Risk Assessment, ambient air quality, atmospheric particulate matter, particulates, air toxics, atmospheric particles, chemical characteristics, toxicology, ambient air monitoring, airborne particulate matter, ozone, environmental risks, exposure, Sulfur dioxide, air pollution, aerosol composition, atmospheric aerosol particles, human exposure, ozone monitoring, PM, exposure assessment

    Progress and Final Reports:

    Original Abstract
  • 1999 Progress Report
  • 2001 Progress Report
  • 2002 Progress Report
  • 2003 Progress Report
  • 2004
  • Final Report

  • Main Center Abstract and Reports:

    R827351    EPA NYU PM Center: Health Risks of PM Components

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827351C001 Exposure Characterization Error
    R827351C002 X-ray CT-based Assessment of Variations in Human Airway Geometry: Implications for Evaluation of Particle Deposition and Dose to Different Populations
    R827351C003 Asthma Susceptibility to PM2.5
    R827351C004 Health Effects of Ambient Air PM in Controlled Human Exposures
    R827351C005 Physicochemical Parameters of Combustion Generated Atmospheres as Determinants of PM Toxicity
    R827351C006 Effects of Particle-Associated Irritants on the Cardiovascular System
    R827351C007 Role of PM-Associated Transition Metals in Exacerbating Infectious Pneumoniae in Exposed Rats
    R827351C008 Immunomodulation by PM: Role of Metal Composition and Pulmonary Phagocyte Iron Status
    R827351C009 Health Risks of Particulate Matter Components: Center Service Core
    R827351C010 Lung Hypoxia as Potential Mechanisms for PM-Induced Health Effects
    R827351C011 Urban PM2.5 Surface Chemistry and Interactions with Bronchoalveolar Lavage Fluid (BALF)
    R827351C012 Subchronic PM2.5 Exposure Study at the NYU PM Center
    R827351C013 Long Term Health Effects of Concentrated Ambient PM2.5
    R827351C014 PM Components and NYC Respiratory and Cardiovascular Morbidity
    R827351C015 Development of a Real-Time Monitoring System for Acidity and Soluble Components in Airborne Particulate Matter
    R827351C016 Automated Real-Time Ambient Fine PM Monitoring System