Review
Toxicological assessment of ambient and traffic-related particulate matter: A review of recent studies

https://doi.org/10.1016/j.mrrev.2006.07.001Get rights and content

Abstract

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 (<PM10) 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 PM10 into account. Therefore, future research should aim at establishing the relationship between toxicity of these smaller fractions in relation to their specific sources.

Section snippets

Particulate air pollution and traffic

Epidemiological studies have demonstrated that exposure to urban particulate matter (PM) is associated with several adverse health effects. Long-term exposure to high concentrations of PM increases the risk of lung cancer, respiratory diseases and arteriosclerosis, whereas short-term exposure peaks can cause exacerbation of several forms of respiratory diseases, including bronchitis and asthma, as well as changes in heart rate variability [1], [2], [3]. The results of epidemiological studies on

Methodological approach

In Pubmed, we searched for publications on ambient PM, PM10, PM2.5, particulates or fine dust in combinations with the search terms traffic, diesel, mutagenicity, cytotoxicity, DNA-reactivity, adducts, oxidative damage, radical formation, metals, elemental composition, PAH, nitro-PAH, quinones and semi-quinones. As we aimed to review the literature on ambient PM samples specifically, results from studies evaluating toxicity and chemical composition of diesel exhaust particles (DEP), or other PM

Chemical characteristics and radical generating capacity of PM

Ambient PM contains biological material, organic compounds, hydrocarbons, acid aerosols and metals absorbed or attached to a carbonaceous core. The TSP and PM10 fractions consist primarily of crustal materials, sea salt and biological factors (including bacteria and pollen) and are generated by mechanical processes rather than combustion. On the other hand, PM2.5 and ultra fine particulates are predominantly produced by combustion processes and consist primarily of metals, hydrocarbons and

Mutagenicity of PM

The Ames mutagenicity test is a short-term in vitro assay that has frequently been used to establish the mutagenicity of ambient and indoor PM [31], [65], [66]. Short-term mutagenicity assays in general can detect the genotoxic effect of either single chemical and physical agents or heterogeneous mixtures, such as ambient PM. As some PAH and other organic molecules require metabolic activation in order to exert their mutagenic activity, metabolising enzymes from rat liver microsomes or S9, are

Cytotoxicity of different PM size fractions

Several different methods have been used to establish the cytotoxicity of PM. The most important distinctions between these tests are the use of various cell types and the time of incubation, varying from 4 to 72 h. Also, different PM fractions and extraction procedures have been used. These differences and variables should be taken into account when results from different studies are compared.

Table 4 shows the results of the most recent studies on the cytotoxicity of PM. Three out of seven

DNA-reactivity of different PM size fractions

Generally, two types of DNA-reactivity have been studied in order to characterise PM genotoxicity, which either focus on the analysis of DNA-adduct formation or on oxidative DNA damage. The latter can be measured either as induction of DNA strand breaks in for instance the Comet assay or as the formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG). The summary presented in Table 5, shows that ten out of eighteen studies demonstrated positive dose–response curves of PM-induced

Chemical composition of specific PM size fractions

Information on particle size distribution is essential to understand the potential health effects of PM exposure. Although there is no strict relation between size distribution and sources of emission, it has been demonstrated that different PM size fractions originate from different types of PM sources and that the chemical speciation and bioavailability of PM components also depend on the source of emission. In order to evaluate differences in chemical composition and toxicological

Final remarks and conclusions

Epidemiological studies have provided ample evidence of a positive association between PM exposure and the induction of serious adverse health effects. As no threshold for PM induced health effects has been established up to now, a certain level of impact of PM on human health probably has to be accepted. Current policies in the EU might lead to reductions of the emissions of PM in general, but current EU standards are only defined for PM10 (annual average of 40 μg/m3; daily average of 50 μg/m3,

References (103)

  • K. Hayakawa et al.

    Distributions of nitropyrenes and mutagenicity in airborne particulates collected with an Andersen sampler

    Mutat. Res.

    (1995)
  • H.L. Sheu et al.

    Particle-bound PAH content in ambient air

    Environ. Pollut.

    (1997)
  • H.S. Rosenkranz

    Mutagenic nitroarenes, diesel emissions, particulate-induced mutations and cancer: an essay on cancer-causation by a moving target

    Mutat. Res.

    (1996)
  • H. Yamazaki et al.

    Bioactivation of diesel exhaust particle extracts and their major nitrated polycyclic aromatic hydrocarbon components, 1-nitropyrene and dinitropyrenes, by human cytochromes P450 1A1, 1A2, and 1B1

    Mutat. Res.

    (2000)
  • A.K. Prahalad et al.

    Ambient air particles: effects on cellular oxidant radical generation in relation to particulate elemental chemistry

    Toxicol. Appl. Pharmacol.

    (1999)
  • B. Fubini et al.

    Reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation by silica in inflammation and fibrosis

    Free Radic. Biol. Med.

    (2003)
  • K. Donaldson et al.

    Free radical activity associated with the surface of particles: a unifying factor in determining biological activity?

    Toxicol. Lett.

    (1996)
  • L.D. Claxton et al.

    A genotoxic assessment of environmental tobacco smoke using bacterial bioassays

    Mutat. Res.

    (1989)
  • M. Cerna et al.

    Genotoxicity of urban air pollutants in the Czech Republic. Part I. Bacterial mutagenic potencies of organic compounds adsorbed on PM10 particulates

    Mutat. Res.

    (2000)
  • M. Cerna et al.

    Mutagenicity monitoring of airborne particulate matter (PM10) in the Czech Republic

    Mutat. Res.

    (1999)
  • A. Buschini et al.

    Urban airborne particulate: genotoxicity evaluation of different size fractions by mutagenesis tests on microorganisms and comet assay

    Chemosphere

    (2001)
  • L.D. Claxton et al.

    A comparative assessment of Boise, Idaho, ambient air fine particle samples using the plate and microsuspension Salmonella mutagenicity assays

    Sci. Total Environ.

    (2001)
  • B. Binkova et al.

    Biological activities of organic compounds adsorbed onto ambient air particles: comparison between the cities of Teplice and Prague during the summer and winter seasons 2000–2001

    Mutat. Res.

    (2003)
  • A. Delgado-Rodriguez et al.

    Genotoxicity of organic extracts of airborne particles in somatic cells of Drosophila melanogaster

    Chemosphere

    (1999)
  • V.A. Du Four et al.

    Genotoxic and mutagenic activity of environmental air samples in Flanders, Belgium

    Mutat. Res.

    (2004)
  • M.I. Sato et al.

    Mutagenicity of airborne particulate organic material from urban and industrial areas of Sao Paulo, Brazil

    Mutat. Res.

    (1995)
  • X. Zhao et al.

    Genotoxic activity of extractable organic matter from urban airborne particles in Shanghai, China

    Mutat. Res.

    (2002)
  • M. Watanabe et al.

    A sensitive method for the detection of mutagenic nitroarenes: construction of nitroreductase-overproducing derivatives of Salmonella typhimurium strains TA98 and TA100

    Mutat. Res.

    (1989)
  • M. Watanabe et al.

    Sensitive method for the detection of mutagenic nitroarenes and aromatic amines: new derivatives of Salmonella typhimurium tester strains possessing elevated O-acetyltransferase levels

    Mutat. Res.

    (1990)
  • E.C. McCoy et al.

    Frameshift mutations: relative roles of simple intercalation and of adduct formation

    Mutat. Res.

    (1981)
  • A. Ducatti et al.

    Mutagenic activity of airborne particulate matter as an indicative measure of atmospheric pollution

    Mutat. Res.

    (2003)
  • C.Y. Kuo et al.

    Correlation between the amounts of polycyclic aromatic hydrocarbons and mutagenicity of airborne particulate samples from Taichung City, Taiwan

    Environ. Res.

    (1998)
  • V.M. Vargas

    Mutagenic activity as a parameter to assess ambient air quality for protection of the environment and human health

    Mutat. Res.

    (2003)
  • L.L. Greenwell et al.

    Particle-induced oxidative damage is ameliorated by pulmonary antioxidants

    Free Radic. Biol. Med.

    (2002)
  • A. Gabelova et al.

    Genotoxicity of environmental air pollution in three European cities: Prague, Kosice and Sofia

    Mutat. Res.

    (2004)
  • E. Brits et al.

    Genotoxicity of PM10 and extracted organics collected in an industrial, urban and rural area in Flanders, Belgium

    Environ. Res.

    (2004)
  • M. Lazarova et al.

    Genotoxic effects of a complex mixture adsorbed onto ambient air particles on human cells in vitro; the effects of Vitamins E and C

    Mutat. Res.

    (2004)
  • B. Dellinger et al.

    The role of combustion-generated radicals in the toxicity of PM2.5

    Proc. Combust. Inst.

    (2000)
  • T. Nielsen

    Traffic contribution of polycyclic aromatic hydrocarbons in the center of a large city

    Atmos. Environ.

    (1996)
  • L. Chiaverini

    Asthma, particulates, and diesel exhaust

    Med. Health RI

    (2002)
  • J.M. Samet et al.

    Fine particulate air pollution and mortality in 20 U.S. cities, 1987–1994

    N. Engl. J. Med.

    (2000)
  • F. Palmgren et al.

    The Pollution of Air with Particles in Copenhagen

    (2003)
  • P. Bagnoli et al.

    Chemical characterization of the PM10 fraction of airborne particulate matter in the urban atmosphere

    J. Environ. Pathol. Toxicol. Oncol.

    (1997)
  • K.S. Chen et al.

    Determination of source contributions to ambient PM2.5 in Kaohsiung, Taiwan, using a receptor model

    J. Air Waste Manage. Assoc.

    (2001)
  • H. Visser et al.

    Composition and Origin of Airborne Particulate Matter in the Netherlands

    (2001)
  • M. Cackovic et al.

    Seasonal distributions of acid components in PM2.5 fraction of airborne particles in Zagreb air

    Bull. Environ. Contam. Toxicol.

    (2001)
  • WHO

    Air Quality Guidelines for Europe

    (2000)
  • USEPA Compilation of Air Pollutant Emission Factors. USEPA report AP-42, US Environmental Protection Agency,...
  • TNO Particulate Mater Emissions (PM10, PM2.5 PM<0.1) in Europe in 1990 and 1993, TNO report TNO-MEP-R96-472, TNO,...
  • W. Birmili et al.

    Trace metal concentrations and water solubility in size-fractionated atmospheric particles and influence of road traffic

    Environ. Sci. Technol.

    (2006)
  • Cited by (418)

    View all citing articles on Scopus
    View full text