Distribution of lead in single atmospheric particles

Abstract

Abstract. Three independent single particle mass spectrometers measured Pb in individual aerosol particles. These data provide unprecedented sensitivity and statistical significance for the measurement of Pb in single particles. This paper explores the reasons for the frequency of Pb in fine particles now that most gasoline is unleaded. Trace amounts of Pb were found in 5 to 25% of 250 to 3000 nm diameter particles sampled by both aircraft and surface instruments in the eastern and western United States. Over 5% of particles at a mountain site in Switzerland contained Pb. Particles smaller than 100 nm with high Pb content were also observed by an instrument that was only operated in urban areas. Lead was found on all types of particles, including Pb present on biomass burning particles from remote fires. Less common particles with high Pb contents contributed a majority of the total amount of Pb. Single particles with high Pb content often also contained alkali metals, Zn, Cu, Sn, As, and Sb. The association of Pb with Zn and other metals is also found in IMPROVE network filter data from surface sites. Sources of airborne Pb in the United States are reviewed for consistency with these data. The frequent appearance of trace Pb is consistent with widespread emissions of fine Pb particles from combustion sources followed by coagulation with larger particles during long-range transport. Industrial sources that directly emit Pb-rich particles also contribute to the observations. Clean regions of the western United States show some transport of Pb from Asia but most Pb over the United States comes from North American sources. Resuspension of Pb from soil contaminated by the years of leaded gasoline was not directly apparent.

Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds

“…Ebert et al, 2000;EPA, 2002). Today, the dominant sources for Pb-rich particles are light aviation fuel (which still contains tetra-ethyl lead), emissions from coal combustion and lead smelters (Murphy et al, 2007). In contrast to previous CLACE campaigns, lot of helicopter traffic occurred in the direct vicinity of the Jungfraujoch station during CLACE 5.…”

“…3). The fact that most Pb bearing particles contain this element only in minor or trace concentrations was also observed for total aerosol samples at a variety of locations by Murphy et al (2007).…”

Clarifying the Dominant Sources and Mechanisms of Cirrus Cloud Formation

“…A few previous field studies have noted metal-rich 'industrial' IN (4,8,28,29). Lead, present in ~5% of ambient particles (30), has been shown to be a particularly efficient IN in the field and laboratory (21,29). Laboratory studies and improved emission inventories coupled to cloud formation models are needed to elucidate the global effect of anthropogenic particles on cirrus.…”

Chemical analysis of refractory stratospheric aerosol particles collected within the arctic vortex and inside polar stratospheric clouds

“…The mass abundance of this component can be very low. Nevertheless, by in situ mass spectrometry measurements Murphy et al (2007b) found lead in 5 to 25 % of all analyzed particles in the upper troposphere. They discussed aviation fuel and coal combustion as a source for these particles.…”

“…They discussed aviation fuel and coal combustion as a source for these particles. A distinct internal contamination source for lead could not be discovered, but because of the ubiquitous distribution of trace amounts of lead in the environment (Murphy et al, 2007b) it cannot completely be excluded.…”