ABSTRACT
The term "technogenic particles" is used to describe airborne particulate matter (PM) produced during industrial processes. The most common of these is "fly ash" produced during combustion of solid and liquid fossil fuels. Coal fly ash is derived from the mineral and metal contaminants within coal in which particles (1) are distinctly spherical in shape, (2) are composed of 60-90% glass, and (3) often contain a range of contaminant metals. In addition, particles may contain recrystallized minerals, mainly quartz, mullite, and hematite; both quartz and mullite are recognized respiratory hazards. Fly ash particles from both UK and Chinese coal-burning power stations were characterized by field emission-scanning electron microscopy (morphology and size), x-ray diffraction (crystallinity and minerals), and inductively coupled plasma-mass spectroscopy (elemental composition). PM(10) samples were separated from bulk fly ash by a dry dust separator system. The plasmid scission assay (PSA) was used to measure damage produced by fly ash to plasmid bacteriophage PhiX174 RF DNA. The supercoiled DNA was either damaged or severely damaged by reactive oxygen species (ROS) generated by the fly ash at different concentrations. Geochemical analyses confirmed that the fly ash particles are predominantly glass, with a minor component of the minerals quartz, hematite, and mullite. Fly ash particles also contained a range of metals contaminants; however, these were mostly bound into the glass with only a small proportion potentially bioaccessible. PSA data showed that fly ash exhibited significant oxidative capacity when compared to negative control (MB H(2)O), indicating that ROS are likely to be the driving force underlying fly ash bioreactivity.
Subject(s)
Air Pollutants/chemistry , Air Pollutants/toxicity , Carbon/chemistry , Carbon/toxicity , Particulate Matter/chemistry , Particulate Matter/toxicity , Bacteriophages/drug effects , Bacteriophages/genetics , Coal Ash , DNA Damage , Microscopy, Electron, Scanning , Oxidants/chemistry , Oxidants/toxicity , Particle Size , Plasmids/drug effects , Plasmids/genetics , Reactive Oxygen Species/metabolism , Toxicity TestsABSTRACT
Monitoring of Beijing PM(10) was undertaken, data collected in a period of one year showed seasonal variation of the mass level of Beijing PM(10) being highest in winter and spring, lower in summer and lowest in autumn. PIXE was used to investigate the chemical elements in PM(10). Results showed the chemical concentration also varied seasonally. Percentage of the masses of the crustal elements such as Al, Si, Mg, K, Ca, Fe, Mn and Ti, reached highest in spring and S, Cl, Pb, As, Cu, Ni and Zn which originated from anthropogenic sources reached highest in winter. The monitoring data showed gradual increase of the abundance of the elements from spring to winter in Beijing air and especially strong correlation of Si, Ca, Al, Fe, Mg and Ti from the factor analysis indicating these elements coming from the earth crust or soil, S, Zn and Pb probably from industrial pollution and Cl and As from combustion.
Subject(s)
Air Pollutants/analysis , Metals/analysis , Particle Size , China , Factor Analysis, Statistical , SeasonsABSTRACT
Objective To study the chemical composition and the sources of indoor PM10 in some residential houses in Beijing. Methods PM10 samples were collected using cascade impactors in smoker's and non-smoker's homes in winter. The mass concentrations and enrichment characteristics of nineteen elements, such as Al, Si, and S in airborne particles were analyzed by proton induced X-ray emission (PIXE) and enrichment factor. Results The concentrations of 19 elements were higher in smoker's homes than those in non-smoker's homes in winter, especially K and S concentrations were 2-4 times of those in non-smoker's homes. Al, Si, S, K, Ca and Fe made greater contribution to concentrations of elements in PM10, of which K and S accounted for 72% of total elements in smoker's homes while Al, Si and Ca amounted to 57% of total elements in non-smoker's homes. Conclusion Al, Si, Ca, Ti and Fe come from natural sources while S, Zn, Pb, Cr, Cu, As, Cl and P originated from anthropogenic sources such as smoking, coal combustion and oil combustion.
ABSTRACT
The significance of the study on the human healht effects of inhalable particulates(PM10) was pointed out,specific properties of inhalable particulates,such as chemical components,aerodynamic behavior and transference in respiratory tract,were then presented.The serious harm of inhalable particulates on human health were summarized based on research results of epidemiological study,animal toxicological study and clinical study,and research emphasis to which should pay more attention in the future study of this aspects was also suggested.
