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At least 703 records · Page 39Linked to original sources
PubMed2006

Toxicological assessment of ambient and traffic-related particulate matter: a review of recent studies.

Particulate air pollution (PM) is an important environmental health risk factor for many different diseases. This is indicated by numerous epidemiological studies on associations between PM exposure and occurrence of acute respiratory infections, lung cancer and chronic respiratory and cardiovascular diseases. The biological mechanisms behind these associations are not fully understood, but the results of in vitro toxicological research have shown that PM induces several types of adverse cellular effects, including cytotoxicity, mutagenicity, DNA damage and stimulation of proinflammatory cytokine production. Because traffic is an important source of PM emission, it seems obvious that traffic intensity has an important impact on both quantitative and qualitative aspects of ambient PM, including its chemical, physical and toxicological characteristics. In this review, the results are summarized of the most recent studies investigating physical and chemical characteristics of ambient and traffic-related PM in relation to its toxicological activity. This evaluation shows that, in general, the smaller PM size fractions (<PM(10)) have the highest toxicity, contain higher concentrations of extractable organic matter (comprising a wide spectrum of chemical substances), and possess a relatively high radical-generating capacity. Also, associations between chemical characteristics and PM toxicity tend to be stronger for the smaller PM size fractions. Most importantly, traffic intensity does not always explain local differences in PM toxicity, and these differences are not necessarily related to PM mass concentrations. This implies that PM regulatory strategies should take PM-size fractions smaller than PM(10) into account. Therefore, future research should aim at establishing the relationship between toxicity of these smaller fractions in relation to their specific sources.

Air Pollutants↗
PubMed2006

[Fine particulate matter - a health hazard for lungs and other organs?].

BACKGROUND: Epidemiological studies provide evidence that particulate air pollution (PM10) increases pulmonary as well as cardiovascular mortality. This review summarises current hypotheses on the mechanisms of entry of inhaled fine particles into the systemic circulation and the mechanisms of action on the cardiovascular system. PARTICLE ENTRY: Following particle deposition in the lungs, soluble components like metal salts or soluble organics are taken up into the pulmonary capillary blood. Ultrafine particles can pass the lung-blood barrier by endocytosis, transcytosis, or stochastic transport, depending on their physicochemical properties, and a fraction (0.1 - 1 %) is thus dislocated into the systemic circulation. MECHANISMS OF ACTION: Direct actions of translocated particles, soluble compounds and/or inflammatory mediators have been shown to alter cardiovascular homeostasis. Effects associated with high PM10 are arrhythmias, myocardial infarction, and cardiac failure. Cardiovascular regulation may be impaired by autonomic imbalances such as those caused by inflammatory or stress-related processes. Local or systemic inflammatory responses may cause endothelial dysfunction, a procoagulatory state with the risk of enhanced atherosclerosis. Cardiac function may be impaired by alterations in ion channel functions leading to electrophysiological instability. OUTLOOK: Systemic actions of inhaled particles are an important issue in environmental health, and there is evidence that they are in no way limited to the cardiovascular system, but also affect other organs like the brain. Details on particle translocation mechanisms and pathophysiological pathways of action remain to be elucidated.

Arrhythmias, Cardiac↗
PubMed2006

A review of atmospheric fine particulate matter and its associated trace metal pollutants in Asian countries during the period 1995-2005.

Many studies have monitored atmospheric particulates and gaseous phases of PM(2.5) in Asia over the past 10 years. This work also compared and discussed different sample collection, pretreatment and analytical methods in Asia countries in past decade. The results indicated that the main PM(2.5) sources are traffic exhausts. PM(2.5) concentrations are also ranked highest in the areas of traffic, followed by the urban sites, and lowest in rural sites in Asian countries. This work elucidates the sources, analytical tools, and the average concentrations for PM(2.5) and related metallic elements during 1995-2005. The results indicated that the average highest concentrations order of metallic elements for PM(2.5) were Fe>Mg>Zn, and the average concentrations of lowest metallic elements was Pb>Cu>Mn>Cr>Cd. The results also indicated that the concentration of metallic element Cu increased as the averaged concentrations of metallic element Zn and Mn increased during the past 10 years in Asian countries.

Air↗
PubMed2004

Aerobic granular sludge in an SBR-system treating wastewater rich in particulate matter.

Aerobic granular sludge was successfully cultivated in a lab-scale SBR-system treating malting wastewater with a high content of particulate organic matter (0.9 gTSS/L). At an organic loading rate (CODtotal) of 3.4 kg/(m3 x d) an average removal efficiency of 50% in CODtotal and 80% in CODdissolved was achieved. Fractionation of the COD by means of particle size showed that particles with a diameter less than 25-50 microm could be removed at 80% efficiency, whereas particles bigger than 50 microm were only removed at 40% efficiency. Tracer experiments revealed a dense sessile protozoa population covering the granules. The protozoa appeared to be responsible for primary particle uptake from the wastewater.

Animals↗