Asthma & Exposure to Peaks in Particulate Air Pollution
Summary
We are testing the following two hypotheses: 1) Peaks in hourly exposures to airborne particulate matter (PM) of outdoor origin will be more closely associated with acute asthmatic responses to particles than 24-hour average exposures in susceptible individuals; 2) Personal exposure to PM, and estimated particle dose to the lungs, will be more closely associated with daily asthma severity than standard outdoor particle concentrations measured as 24-hour averages at governmental monitoring sites.
Description
We are testing the following two hypotheses: 1) Peaks in hourly exposures to airborne particulate matter (PM) of outdoor origin will be more closely associated with acute asthmatic responses to particles than 24-hour average exposures in susceptible individuals; 2) Personal exposure to PM, and estimated particle dose to the lungs, will be more closely associated with daily asthma severity than standard outdoor particle concentrations measured as 24-hour averages at governmental monitoring sites. Toxicological data for asthma exacerbations from particulate matter (PM) suggests that particle deposition in the lower respiratory tract can cause inflammatory and lung function changes suggestive of asthma pathology. There is now a scientific need to explain epidemiological findings of ambient PM effects on asthmatics at mass concentrations below what is expected (from toxicological data) to be harmful. One possibility is that study participants are encountering unmeasured short-term excursions of particle mass levels capable of inducing adverse reactions in the lung, but this effect is only captured somewhat by the regulatory standard of 24-hour averages. Our research in southern California is vital to the current controversy regarding regulatory standards given that a health-based scientific rationale for any specific PM averaging time is not established.
Study Design
Observational Model: Defined Population, Observational Model: Natural History, Time Perspective: Longitudinal, Time Perspective: Prospective
Conditions
Asthma
Status
Completed
Source
National Institute of Environmental Health Sciences (NIEHS)
Results (where available)
Links
- Source: http://clinicaltrials.gov/show/NCT00013728
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Asthma, Exercise-induced
Asthma attacks following a period of exercise. Usually the induced attack is short-lived and regresses spontaneously. The magnitude of postexertional airway obstruction is strongly influenced by the environment in which exercise is performed (i.e. inhalation of cold air during physical exertion markedly augments the severity of the airway obstruction; conversely, warm humid air blunts or abolishes it).
Anti-asthmatic Agents
Drugs that are used to treat asthma.
Orciprenaline
A beta-adrenergic agonist used in the treatment of asthma and bronchospasms.
Tretoquinol
An adrenergic beta-agonist used as a bronchodilator agent in asthma therapy.
Isoetharine
Adrenergic beta-2 agonist used as bronchodilator for emphysema, bronchitis and asthma.
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