Determination of carbon black in urban air

Abstract

<p>The City of Hamilton is one of the most heavily industrialized cities in Canada. In recent years, residents of communities in the east-end of Hamilton have complained about "black fallout" on their properties; this air particulate deposition takes the form of a fine, greasy black film that coats their houses, cars, etc. A carbon black production company has been suspected as the primary source of this black particulate, although there are other potential sources of black particulate, including emissions from two large steel industries, vehicular traffic and other sources. One of the major problems that has faced the Ministry of the Environment (MOE) in dealing with public complaints regarding "black fallout" has been the lack of an analytical procedure that would allow carbon black and other types of "black fallout" to be distinguished. My focus has been to develop the first analytical methodology to identify and quantify carbon black in ambient air. This approach to the determination of ambient levels of carbon black is based upon a sequential extraction methodology and the gas chromatography-mass spectrometric (GC-MS) quantification of an unusual polycyclic aromatic compound (PAC) I have identified on carbon blacks (thiacoronene) as a source tracer for carbon black. In an air monitoring study carried out from 1995 to 1998, I have been able to identify and quantify carbon black in ambient air samples collected downwind of a carbon black production plant, which varied from 0.01 to 1.43 μg carbon black/m3 of air. All concentrations of carbon black were well above the method detection limit of 0.004 μg/m3 with an uncertainty estimate of less than 5%. In the evaluation of sources of "black fallout" other than carbon black, I investigated a new source apportionment strategy based on a manganese-tin (Mn-Sn) metal index to differentiate levels of steel industry impacts in ambient air.</p>