Observation of smoke may be helpful in obtaining an indication of the type of the fuel. Smoke color, especially colors other than the neutral white, gray, or black, may give indications of special types of fuel being combusted if they are present in large amounts. Smoke that has an unusual hue, such as red-brown or yellow, may indicate the presence of materials other than conventional building materials and furnishings.

觀察煙氣可能有助于了解可燃物的類型。煙氣顏色，特別是有別于常見的白色、灰色或黑色以外的顏色，能表明有大量特定類型的可燃物參與燃燒。紅棕色或黃色等特殊顏色的煙氣則表明可能存在常規(guī)建材和家具以外的材料。

When complete combustion occurs, most materials produce little or no visible smoke. Under these ideal conditions, all carbon is burned to carbon dioxide, a colorless gas. Incomplete combustion of carbon leads to carbon monoxide, also colorless and odorless but having very toxic properties. Incomplete combustion of carbonaceous materials also produces various highly carbonaceous compounds that are opaque, such as soot, which is largely carbon.

當發(fā)生完全燃燒時，多數(shù)材料只產(chǎn)生少量的或不可見的煙。在這種理想條件下，所有的碳燃燒生成無色氣體二氧化碳。碳的不完全燃燒會產(chǎn)生一氧化碳，也是無色無味的，但具有很強的毒性。含碳物質(zhì)的不完全燃燒還會產(chǎn)生各種不透明的含碳量高的化合物，如主要成分是碳的煙炱。

Hydrogen, present in all organic materials, burns to water vapor, a major constituent of all combustion gases. It does not contribute to the smoke characteristics, although it may at times be recognized as steam. Other elements often present in organic materials, such as nitrogen, sulfur, and halogens, contribute gases to the combustion products. However, only under very special conditions do these alter the color of the smoke. They may contribute strongly to its odor when present in larger-than-ordinary amounts. Such effects may be encountered in industrial fires but rarely in residential ones.

所有有機材料中都含有氫，氫燃燒產(chǎn)生的水蒸氣是燃燒產(chǎn)物的主要成分之一。有時認為產(chǎn)物是蒸汽（vapor，物質(zhì)的氣態(tài)形式；steam，水受熱蒸發(fā)產(chǎn)生的蒸汽），但對煙氣的特性沒有影響。有機材料中常存在其他元素，如氮、硫和鹵素，這增加了燃燒產(chǎn)物中的氣體類型。然而，只有在非常特殊的條件下，這些元素才會改變煙氣的顏色。當其含量高于正常值時，會產(chǎn)生強烈的氣味。這種現(xiàn)象在工業(yè)火災中可能遇到，但很少出現(xiàn)在住宅火災中。

The color of smoke is almost entirely determined by the character and type of fuel and the availability of oxygen for complete combustion. Most materials, including all hydrocarbons, will never burn completely even in the presence of excess air, without premixing of the fuel with air. This is true of natural gas when burning in large volumes.

煙氣的顏色幾乎完全由可燃物性質(zhì)、類型以及氧氣供給情況決定。包括所有碳氫化合物在內(nèi)的大多數(shù)材料，如果未與空氣預混，即使在空氣供給過量的情況下也不會發(fā)生完全燃燒。大量天然氣燃燒時也是如此。

As the hydrocarbon molecules become larger, such as those in petroleum oils, more air is required, and it becomes more difficult to completely mix the fuel with air. Thus, in an ordinary fire, materials such as petroleum distillates tend to produce a large quantity of dense black smoke. Therefore, the presence of much black smoke may indicate the burning of a highly carbonaceous material like the petroleum products sometimes used as accelerants. Dense black smoke, however, is usually more indicative of the amount of ventilation and the stage of development at which the fire is burning. For example, fire burning in a restricted space without adequate and complete ventilation will always form more smoke and darker smoke than when the same fire is well ventilated.

隨著碳氫化合物分子增大，比如石油中的分子，其燃燒需要更多的空氣，且可燃物與空氣完全混合難度變得更大。因此，一般火災中，石油餾出物等材料往往產(chǎn)生大量的濃密黑煙（見圖1）。因此，出現(xiàn)大量黑煙的現(xiàn)象可能表明燃燒過程中存在含碳量較高的材料，如有時作為助燃劑的石油產(chǎn)品。然而，濃密的黑煙通常更能反映通風狀況以及火災所處的發(fā)展階段。例如，相較于通風良好的火災，受限空間通風不足，燃燒經(jīng)常會產(chǎn)生更多顏色更深的煙氣。