Fractions Of Urban Particulate Matter Research Articles

Redox activity and in vitro bioactivity of the water-soluble fraction of urban particulate matter in relation to particle size and chemical composition

Chemical and toxicological characterization of the water-soluble fraction of size-segregated urban particulate matter (PM) (<0.49, 0.49–0.97, 0.97–1.5, 1.5–3.0, 3.0–7.2 and >7.2 μm) was carried out at two urban sites, traffic and urban background, during the cold and the warm period. Chemical analysis of the water-soluble PM fraction included ionic species (NO3−, SO42−, Cl−, Na+, NH4+, K+, Mg2+, Ca2+), water-soluble organic carbon (WSOC), and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Zn, Pt, Pd, Rh, Ru, Ir, Ca, and Mg). The dithiothreitol (DTT) assay was employed for the abiotic assessment of the oxidative PM activity. Cytotoxic responses were investigated in vitro by applying the mitochondrial dehydrogenase (MTT) and the lactate dehydrogenase (LDH) bioassays on human lung cells (MRC-5), while DNA damage was estimated by the single cell gel electrophoresis assay, known as Comet assay. The correlations between the observed bioactivity responses and the concentrations of water-soluble chemical PM constituents in the various size ranges were investigated. The results of the current study corroborate that short-term bioassays using lung human cells and abiotic assays, such as the DTT assay, could be relevant to complete the routine chemical analysis and to obtain a preliminary screening of the potential effects of PM-associated airborne pollutants on human health.

Concentrations and Estimated Soot Content of PM1, PM2.5, and PM10in a Subarctic Urban Atmosphere

Mass concentrations of ambient particulate matter were measured in terms of daily average values of PM1, PM2.5, and PM10 for 6 months during the winter of 1996−1997 at a fixed sampling site in Helsinki, Finland, along with meteorological parameters and particle number concentra tions in the size range 0.01−1 μm. In addition, the PM filters were subjected to reflectometric analysis to determine absorption coefficients for the various fractions of urban particulate matter. The data were divided into two periods (winter and spring) in order to study more closely seasonal phenomena that have an effect on air pollution patterns. The variations in PM10 and PM2.5 concentrations differed in pattern during resuspended dust episodes, whereas those in PM1 concentrations followed those in PM2.5 fairly well throughout the 6-month measurement period. Thus it seems that PM1 does not provide much additional information on mass concentrations relative to PM2.5. Number concentrations in the ultrafine particle size range fr...

Mutagenic Activity of Total and Particle-Sized Fractions of Urban Particulate Matter

Total or inhalable (PM 10 ) particulate matter is monitored as a quality air criteria. Airborne particles deposit onto the differently sensitive biological tissues of the respiratory tract depending on their size. So it is very important to know the mutagenic activity (index of potential carcinogenicity) of the substances carried onto the diverse sized fractions of urban particulate matter, especially those under 1 μm in diameter. The mutagenicity of total and sized fractions of urban particulate matter of Bologna (Italy), representative of a medium size town surrounded by small and medium industries, was investigated using the plate incorporation test on Salmonella typhimurium. There is no correlation between total and/or coarse particle matter concentration in air and mutagenic activity, the correlation increases as the particle size decreases ; moreover, the finer the particulate matter, the greater the mutagenicity is. That is of great concern for health risk estimation. Total or inhalable (PM 10 ) particulate matter is not representative of air quality, at least with regard to the mutagenicity.

ORGANIC COMPOUNDS IN URBAN AEROSOLS*

Over the past 25 years, much information has been obtained on the biological, physical, and chemical properties of particular organic matter (POM). Organic fractions of urban particulate matter have been found to be tumorigenic in mice and mutagenic in certain strains of bacteria, indicating that such materials may be significant in the etiology of environmental diseases. Hundreds of organic compounds have been identified in the organic aerosol. It is suggested that as sampling and analytical methods become more sophisticated, it will be possible to identify hundreds more and to see more clearly the composition differences between sources, sampling locations, and seasons. The paper reviews the properties of POM in urban atmospheres and considers methods for determining the sources of POM, with emphasis on long-term trends, seasonal variations, diurnal patterns, and transport characteristics.