Ultrafine Particles

Introduction

Characteristics of Ultrafine Particles

Transport and Fate in the Environment

Measuring Exposure

Exposure Pathways

Prevention or Control of Exposures

Human Health Effects of Ultrafine Particles


Effects

Absorption and Distribution

Biomarkers

Risk Assessment

Works Cited


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Effects

Association has been observed between ambient ultrafine particulate concentrations and adjusted mortality rates, particularly for respiratory and cardiac deaths among the elderly. Particulate pollution is also associated with increased rates of asthma and increased hospital admissions. Other adverse health effects observed in humans in association with exposure to ultrafine particulate include increased medication usage and lost time from work and school. Detailed animal studies have been done, helping scientists understand many of the effects observed in humans. In one study, exposure of particulate matter in humans has been associated with increased morbidity and mortality from pneumonia (Shwartz, 1994). In children, studies have demonstrated an association between ultrafine particulate exposure and slower growth of lung function. In fact, studies on the rat lung have shown that inhalation of ultrafine particles leads to inflammation, hyperplasia, and neoplasia.

Human and animal studies link ambient particulate matter with cardiovascular pathology. These effects are most severe in the elderly, frail, and most recently diabetics. There have also been associations demonstrating increased adverse health effects, including mortality, and proximity to combustion sources. In one study, exposure of particulate matter in humans has been associated with increased morbidity and mortality from pneumonia (Shwartz, 1994). After a single 5 hour inhalation exposure of ultrafine particulates, bacterially infected rats demonstrated altered pulmonary and systemic immunity, with an exacerbation in the infection process in a time dependent fashion (Zelikoff 1999). Human volunteers in Los Angeles, exposed to ultrafine particulate inhalation demonstrated decreased heart rate variability in young adults, increased markers of inflammation, decreases in arterial oxygen saturation in elderly, and an increased number of variable heartbeats (Frampton sub). In children, studies have demonstrated an association between ultrafine particulate exposure and slower growth of lung function. Acute exposure to ultrafine particulate exposure has been associated with heart rate and rhythm disturbances, QT changes on electrocardiogram, and cardiac ischemia.

It has been demonstrated in hospital admission coefficients that increased fractions of particulate matter from traffic related sources is associated with increased numbers of cardiovascular related admissions. This suggests an increased relative risk of hospital related cardiovascular admissions in cities with a greater number of particulate matter sources (Janssen 2001).