Particulate air pollution, systemic oxidative stress, inflammation, and atherosclerosis

Controlled exposure of healthy young volunteers to ozone causes cardiovascular effects

BACKGROUND

Recent epidemiology studies have reported associations between short-term ozone exposure and mortality. Such studies have previously reported associations between airborne particulate matter pollution and mortality, and support for a causal relationship has come from controlled-exposure studies that describe pathophysiological mechanisms by which particulate matter could induce acute mortality. In contrast, for ozone, almost no controlled-human-exposure studies have tested whether ozone exposure can modulate the cardiovascular system.

METHODS AND RESULTS

Twenty-three young healthy individuals were exposed in a randomized crossover fashion to clean air and to 0.3-ppm ozone for 2 hours while intermittently exercising. Blood was obtained immediately before exposure, immediately afterward, and the next morning. Continuous Holter monitoring began immediately before exposure and continued for 24 hours. Lung function was performed immediately before and immediately after exposure, and bronchoalveolar lavage was performed 24 hours after exposure. Immediately after ozone exposure, we observed a 98.9% increase in interleukin-8, a 21.4% decrease in plasminogen activator inhibitor-1, a 51.3% decrease in the high-frequency component of heart rate variability, and a 1.2% increase in QT duration. Changes in interleukin-1B and plasminogen activator inhibitor-1 were apparent 24 hours after exposure. In agreement with previous studies, we also observed ozone-induced drops in lung function and an increase in pulmonary inflammation.

CONCLUSIONS

This controlled-human-exposure study shows that ozone can cause an increase in vascular markers of inflammation and changes in markers of fibrinolysis and markers that affect autonomic control of heart rate and repolarization. We believe that these findings provide biological plausibility for the epidemiology studies that associate ozone exposure with mortality.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01492517.

Breathing easier? The known impacts of biodiesel on air quality

Substantial scientific evidence exists on the negative health effects of exposure to petroleum diesel exhaust. Many view biodiesel as a 'green', more environmentally friendly alternative fuel, especially with respect to measured reductions of particulate matter in tailpipe emissions. Tailpipe emissions data sets from heavy-duty diesel engines comparing diesel and biodiesel fuels provide important information regarding the composition and potential aggregate contribution of particulate matter and other pollutants to regional airsheds. However, exposure - defined in this instance as human contact with tailpipe emissions - is another key link in the chain between emissions and human health effects. Although numerous biodiesel emissions studies exist, biodiesel exposure studies are nearly absent from the literature. This article summarizes the known impacts of biodiesel on air quality and health effects, comparing emissions and exposure research. In light of rapidly changing engine, fuel and exhaust technologies, both emissions and exposure studies are necessary for developing a fuller understanding of the impact of biodiesel on air quality and human health.

Environmental determinants of chronic disease and medical approaches: recognition, avoidance, supportive therapy, and detoxification

The World Health Organization warns that chronic, noncommunicable diseases are rapidly becoming epidemic worldwide. Escalating rates of neurocognitive, metabolic, autoimmune and cardiovascular diseases cannot be ascribed only to genetics, lifestyle, and nutrition; early life and ongoing exposures, and bioaccumulated toxicants may also cause chronic disease. Contributors to ill health are summarized from multiple perspectives--biological effects of classes of toxicants, mechanisms of toxicity, and a synthesis of toxic contributors to major diseases. Healthcare practitioners have wide-ranging roles in addressing environmental factors in policy and public health and clinical practice. Public health initiatives include risk recognition and chemical assessment then exposure reduction, remediation, monitoring, and avoidance. The complex web of disease and environmental contributors is amenable to some straightforward clinical approaches addressing multiple toxicants. Widely applicable strategies include nutrition and supplements to counter toxic effects and to support metabolism; as well as exercise and sweating, and possibly medication to enhance excretion. Addressing environmental health and contributors to chronic disease has broad implications for society, with large potential benefits from improved health and productivity.