This invention provides methods for reducing a spark rate and/or increasing the voltage in a cold-side electrostatic precipitator through which a particulate-containing gas stream is directed, wherein said electrostatic precipitator has a spark rate and a voltage. The methods comprise injecting an amount of a halogenated carbonaceous substrate formed from a carbonaceous substrate and an elemental halogen and/or a hydrohalic acid into the particulate-containing gas stream upstream of the electrostatic precipitator, such that the spark rate decreases by about 40% or more and/or such that the voltage can be increased by about 20% or more than when said halogenated carbonaceous substrate is not injected.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 The work leading to the invention described in this patent application was made with Government support under Contract No. DE-FC26-05NT42308 awarded by the Department of Energy, National Energy Technology Laboratory. The Government may have certain rights in this invention.