Combustible heat source for a smoking article

A smoking article comprising:

• an aerosol-generating substrate;
• and
• a combustible heat source upstream from the aerosol-generating substrate, the combustible heat source comprising;
• carbon and at least one ignition aid selected from the group consisting of metal nitrate salts having a thermal decomposition temperature of less than about 600° C., chlorates, peroxides, thermitic materials, intermetallic materials, magnesium, zirconium, and combinations thereof, wherein the at least one ignition aid is present in an amount of at least about 20 percent by dry weight of the combustible heat source,
• the combustible heat source comprising a first portion being an upstream end and an opposed second portion being a downstream end, wherein at least part of the combustible heat source between the first portion and the second portion is wrapped in a combustion resistant wrapper that is one or both of heat conducting and substantially oxygen impermeable, and
• wherein upon ignition of the first portion of the combustible heat source the second portion of the combustible heat source increases in temperature to a first temperature and wherein during subsequent combustion of the combustible heat source the second portion of the combustible heat source maintains a second temperature lower than the first temperature.

A smoking article comprising:

• an aerosol-generating substrate;
• and
• a combustible heat source upstream from the aerosol-generating substrate, the combustible heat source comprising:
• carbon and at least one ignition aid, wherein the at least one ignition aid is present in an amount of at least about 20 percent by dry weight of the combustible heat source and wherein the at least one ignition aid comprises a peroxide or superoxide that actively evolves oxygen at a temperature of less than about 600° C.,
• the combustible heat source comprising a first portion being an upstream end and an opposed second portion being a downstream end, wherein at least part of the combustible heat source between the first portion and the second portion is wrapped in a combustion resistant wrapper that is one or both of heat conducting and substantially oxygen impermeable, and
• wherein upon ignition of the first portion of the combustible heat source the second portion of the combustible heat source increases in temperature to a first temperature and wherein during subsequent combustion of the combustible heat source the second portion of the combustible heat source maintains a second temperature lower than the first temperature.