Grantee Research Project Results
Final Report: Long-Term Morbidity and Mortality Related to Exposures to Particulate Matter and Associated Air Pollutants
EPA Grant Number: R826777Title: Long-Term Morbidity and Mortality Related to Exposures to Particulate Matter and Associated Air Pollutants
Investigators: Lebowitz, Michael , O'Rourke, Mary Kay , Hill, A. , Pettygrove, S.
Institution: University of Arizona
EPA Project Officer: Chung, Serena
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Amount: $363,426
RFA: Health Effects of Particulate Matter and Associated Air Pollutants (1998) RFA Text | Recipients Lists
Research Category: Air , Human Health , Particulate Matter
Objective:
There is a wealth of information indicating that particulate matter (PM) produces chronic pulmonary disease, but knowledge of the effects of PM on chronic cardiovascular disease currently is not sufficient. Furthermore, the nature of the relationships between PM and chronic cardio-pulmonary diseases has needed further exploration, including the potential biological mechanisms involved, the characteristics of people that make them potentially susceptible to cardio-pulmonary effects from air pollutants, and the differential effects of different size and species of PM. More recently, the impact of PM on cardio-pulmonary mortality (death) has become a very important issue, with many issues of biological plausibility remaining unresolved. This research project examined the nature of these relationships of morbidity (illness/disease), utilizing a unique study of longitudinal cardio-pulmonary and related host susceptibility data linked to unique exposure assessment data.
The primary objective of this research project was to determine the chronic cardio-pulmonary morbidity in normal and susceptible individuals associated with indoor and ambient/outdoor exposures to PM (primarily PM10). Chronic cardio-pulmonary responses to PM were examined independently and in interactions with associated indoor and outdoor air pollutants (AP), and related environmental factors. Various host characteristics of potential susceptibility were incorporated in the analyses.
Summary/Accomplishments (Outputs/Outcomes):
Measures of cardio-pulmonary disease in a long-term study of a Tucson representative population of more than 3,000 subjects, previously followed for 26 years, were related to their PM and other AP exposures. The PM and AP exposures have been more than sufficient to affect these populations acutely, and the measures of susceptibility were important in estimating the long-term health responses.
The exposure assessments (EAs) utilized prior indoor/outdoor monitoring and EA modeling, considering various other exposure factors. Historical (residential and occupational) data and environmental data collected in these cohort studies will provide the data for EA modeling in which a parallel EA survey, the Arizona National Human Exposure Assessment Survey (NHEXAS), was used to obtain the estimates of total air exposures to PM, and other relevant AP. Various multivariate statistical analyses also were utilized.
EA Models. People spend a significant proportion of time at home, so household PM10 concentrations make an important contribution to total exposure. Five factors affect indoor PM10 concentrations: (1) indoor sources; (2) outdoor concentration; (3) household ventilation parameters; (4) resuspension of previously deposited particles; and (5) removal by air filters. Household exposures to PM10 and particulate metals were measured in the NHEXAS study. The population was chosen using population-based probabilistic sampling. PM10 was collected using low-flow impactors inside and out at 179 households. Questionnaires were used to assess household activities affecting exposure levels.
Indoor PM10 concentration ranged from below the detection limit (BDL) (0.77 µg/m3) to 211.7 µg/m3, and 1.2 percent (n = 2) were BDL. The mean indoor concentration of PM10 was 40.6 µg/m3; the median was 31.3 µg/m3. Outdoor values ranged from BDL to 115.9 µg/m3, and 9.9 percent (n = 17) were BDL. The mean outdoor concentration was 27.2 µg/m3; the median was 24.5 µg/m3. This study examined indoor air concentrations of PM10 in NHEXAS homes and the relative importance of factors affecting particle concentration. We generated a predictive model of PM10 concentration based on questionnaire data.
Each of the five influences had some effect on indoor concentrations: (1) cigarette smoking had the most significant effect on PM10, and other inside sources (i.e., use of a wood stove) also were related; (2) outdoor concentrations were significantly correlated with indoor concentrations; (3) ventilation parameters such as hours per day of open doors and windows were significant in models that included outdoor concentrations; (4) removal of particles affected the concentration: use of an air filter was significant and PM10 concentrations in samples collected during the rainy season were significantly lower, presumably due to scrubbing by the rain; and (5) resuspension was not as important as indoor and outdoor sources: although vacuuming and dusting might be expected to increase the concentration of PM10 in the air through resuspension, they were not significant in any models. Sitting on the carpet was a resuspension activity associated with elevated concentrations. A model was developed to predict indoor PM10 concentrations from questionnaire data only. The coefficient for each term was significant (p <0.05), and the model R2 = 0.576. This model was applied to an independent exposure data set collected in 1987-1992 in more than 300 households in Tucson, and there was agreement. These results were reported at the annual meeting of the International Society for Exposure Analysis in 2000.
The Relation of Total Exposure Estimates to Cardio-Pulmonary Disease. A significant exposure-response relationship between PM and the development of pulmonary morbidity (disease and symptoms) was found. Specifically, chronic bronchitis was 1.45 (i.e., 45 percent more) prevalent in those with higher PM10 exposures. There was a good likelihood that PM exposures are related to cardiovascular disease as well, as we found that new heart problems during the study were 4.6 times more likely in those with higher PM exposures. These results were true for age, gender, and smoking. A manuscript with these results has been submitted for publication.
These findings demonstrated the importance of measurement of individuals' environments. Because of the poor relationship of concentrations from single stationary PM monitors to actual exposures and the related health responses, the exact nature of the exposure-response relationships using such data still can be considered hypothetical. Other exposure estimation errors from use of stationary monitors likely will be very critical in the exposure-response relationships as well.
Improvements in Risk Assessment or Risk Management: Risk Assessment and Management. It was hypothesized that the findings will significantly improve risk assessment, due to the improvements in exposure-response relationships examined by this research project. We believe that risk assessments now can be improved with better characterization of the total PM exposure assessment estimates. The specification of size and certain composition elements, and the contributions of various other factors and error estimates to those estimates would further help risk assessment. Improved risk assessments, and improved understanding of both the type of PM that requires control and the subjects at higher risk, should be able to improve risk management.
Journal Articles:
No journal articles submitted with this report: View all 2 publications for this projectSupplemental Keywords:
ambient air, ozone, indoor air, mobile sources, vulnerability, sensitive populations, population, age, sex, ethnic groups, cumulative effects, toxins, volatile organic compounds, VOCs, nitrogen oxides, decision-making, socioeconomic, epidemiology, statistics, biology, medicine, physiology, immunology, monitoring, analytical, surveys, measurement methods, EPA Region 9, Arizona, AZ., RFA, Scientific Discipline, Health, Air, Geographic Area, particulate matter, Environmental Chemistry, Health Risk Assessment, Epidemiology, State, Risk Assessments, Susceptibility/Sensitive Population/Genetic Susceptibility, Biochemistry, Children's Health, indoor air, genetic susceptability, ambient air quality, particulates, PM10, sensitive populations, air toxics, cardiopulmonary responses, human health effects, morbidity, cardiovascular vulnerability, exposure, ozone, pulmonary disease, host susceptibility, air pollution, socioeconomics, Tucson, children, human exposure, cardiopulmonary mechanisms, chronic health effects, lung inflammation, mobile sources, Arizona (AZ), cardiopulmonary response, mortality studies, Acute health effects, elderly, indoor air quality, mortality, Volatile Organic Compounds (VOCs), metals, respiratory, environmental hazard exposuresProgress 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.