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MERCURY EMISSIONS FROM GASOLINE AND DIESEL POWERED ON-ROAD VEHICLES
Citation:
LANDIS, M. S., A. F. VETTE, M. CHRISTIANSON, AND G. J. KEELER. MERCURY EMISSIONS FROM GASOLINE AND DIESEL POWERED ON-ROAD VEHICLES. Presented at 8th International Conference on Mercury, Madison, WI, August 06 - 11, 2006.
Impact/Purpose:
The overall research objective of this task is to improve our understanding of the emission, transport, transformation, and deposition of atmospheric mercury. Information garnered from this research is used to improve and evaluate EPA deterministic models that are used to investigate the (i) relative impact to local, regional, and global sources to atmospheric mercury deposition, and (ii) benefits of various emission reduction scenarios.
Specifically, individual research project objectives are listed below:
(1) Evaluate the ability of speciated mercury (Hg0, Hg2+, HgP) measurements to aid source apportionment models in identifying anthropogenic source contributions to atmospheric mercury deposition
(2) Elucidate the contribution of coal combustion sources to observed mercury wet deposition in the Ohio River Valley
(3) Obtain atmospheric profiles (200 - 12,000 ft) of speciated ambient mercury off the south Florida Coast
- Evaluate the role of long range transport of RGM to Florida in the marine free troposphere.
- Identify any vertical mercury gradients that might indicate the presence of rapid mercury chemistry in air or in cloud water.
(4) Conduct research at Mauna Loa Observatory to elucidate elemental mercury oxidation in the remote marine free troposphere.
(5) Conduct laboratory kinetics experiments to determine the rate constants of elemental mercury oxidation to gaseous inorganic divalent mercury species from atmospheric halide species (e.g. BrO, ClO).
Description:
Measurements of elemental gaseous mercury (Hg0), divalent reactive gaseous mercury (RGM), and particulate phase mercury (Hg(p)) were made from 14 gasoline and 2 diesel powered in-use light-duty vehicles on a chassis dynamometer. All vehicles were tested under both cold and hot start conditions on a variable speed urban driving cycle. Gas phase species dominated mercury emissions from all vehicles. The mass emission rates and the relative proportion of Hg0 and RGM varied significantly between vehicles and between hot and cold start conditions. Speciated mercury emission rates, mercury in fuel, and mercury in lubricating oil will be presented and discussed.