Concentrations, phase partitioning and deposition of specific alkyl-lead compounds in the atmosphere

Abstract

Measurements of alkyl‐lead compounds in air and rain at rural and urban sites in central England during 1996 are reported. Vapour, aerosol and rain concentrations of individual tetra‐, tri‐ and di‐alkyl‐lead species have been determined simultaneously at both sites, along with inorganic lead aerosol. The results show the predominance of vapour‐phase over particle‐associated species, with tetramethyl‐lead being the most prevalent vapour‐phase compound, with concentrations of up to 5.8 ng Pb m−3. Theoretical phase‐partitioning coefficients for individual alkyl‐lead compounds have been calculated and compared with measured values. Washout ratios for alkyl‐lead compunds were found to be smaller than for inorganic lead. Atmospheric concentrations of both organic and inorganic lead appear to be falling, broadly in line with recent reductions in the use of alkyl‐lead in gasoline. © 1997 John Wiley & Sons, Ltd.

Distribution of lead in single atmospheric particles

“…Of these, it is likely that coagulation is much more important. Gas phase Pb compounds are present only at very low concentrations (Wang et al, 1997;Shotyk and Le Roux, 2005). Another argument in favor of coagulation is that even in the areas with the most Pb many mass spectra with excellent signal to noise showed no Pb.…”

“…Lead and its common sulfur and oxygen compounds are solids at room temperature. Therefore, airborne Pb is predominately particulate, with at most a few percent present as gas phase alkyl compounds (Wang et al, 1997;Shotyk and Le Roux, 2005). In most places most of the Pb is on particles smaller than 1 µm diameter.…”

Speciation of Metals in the Atmosphere

“…The relative significance of lead sources in the atmosphere is currently changing worldwide as a result of the phasing out of leaded fuels in the United States and the decline in European usage. Atmospheric lead concentrations at Bermuda and in the United States and Canada have decreased 10-fold since the early 1970s (Huang et al, 1996) and atmospheric levels of both organic and inorganic lead are falling broadly in line with reductions in usage of alkyl lead in the UK (Wang et al, 1997). In response to declining atmospheric levels, a resultant decrease of 30-40% in surface water lead concentrations in the western North Atlantic Ocean was seen between 1979 and 1989 (Veron et al, 1993) and it is now suggested that European sources contribute 25-40% of the lead input to the Sargasso Sea (Veron et al, 1993;Huang et al, 1996).…”

Trace Metal Speciation with ICP‐MS Detection

“…This technique implies that the species selective adsorption is ensured for all kinds of sample matrix and species concentration, which is a difficult task. Other authors employ trapping of organolead species on a mixture of the sorbents Tenax and Porapak 17,18 or trapping of SbMe 3 . 19 While organolead species seem to be stable for at least 45 days when stored at 4 • C, SbMe 3 is less stable.…”