非甲烷总烃(NmHc)，总挥发性有机化合物(TVOCs)？

   VOCs即挥发性有机物今年以来被学界和公众给予了很高的关注度，是因为其被证明了是形成PM2.5和O3的关键前体物，是复合型大气污染的重要诱因。与传统大气污染物相比，VOCs的污染源广泛，涉及多行业不同的污染物，组分复杂，治理技术多样，且以无组织排放为主，排放量的核算程序复杂。由于我国并未开始对VOCs进行大规模监测，因此相关数据缺失。有研究表明，我国每年的VOCs排放量大约为3000万吨。VOCs的来源分为自然源分和人为源，我国空气中的VOCs主要来自于人为源，重点行业包括工业涂装、包装印刷、油品储运、石油炼制与化工等。

    （NmHc），又称非甲烷总烃。《大气污染物综合排放标准详解》中定义为：指除甲烷以外所有的总称，主要包括烷烃、烯烃、芳香烃和含氧烃等组分。

       烃类物质在通常条件下，除甲烷外多以液态或固态存在，并依据其分子量大小和结构形式的差别具有不同的蒸气压，因而作为大气污染物的，实际上是指具有C2～C12的烃类物质。

烃类物质具有易燃易爆的特性，其具体的物理视单体组成及浓度而定。

       通常认为，沸点高于260℃的化合物的挥发排放速率可以忽略不计，因此不考虑在20℃条件下蒸气压的下限（0.01kpa）是可以的，对总挥发性有机化合物的各种定义差别不大，也就可简明统一为：熔点低于室温而常压下沸点在260℃以下的具有挥发性的全部有机化合物的统称。

       总之，总挥发性有机化合物（TVOCs）和非甲烷总烃(NmHc)是两个不同的概念，但大多数情况下又是一致的，总挥发性有机化合物所涵盖的范畴大于非甲烷总烃。

VOCs, volatile organic compounds (VOCs), have received high attention from the academic community and the public this year because they have proved to be a key precursor to PM2.5 and O3 formation and an important cause of complex atmospheric pollution. Compared with the traditional atmospheric pollutants, VOCs has a wide range of pollution sources, involving many industries with different pollutants, complex components, diversified treatment technologies, and mainly discharges without organization. The accounting procedures of emissions are complex. Since VOCs has not been monitored on a large scale in China, relevant data are missing. Studies have shown that VOCs emissions in China are about 30 million tons per year. The sources of VOCs are divided into natural sources and artificial sources. The VOCs in China's air mainly come from human sources, and the key industries include industrial painting, packaging printing, oil storage and transportation, petroleum refining and chemical engineering, etc.

(NmHc), also known as non-methane total hydrocarbon. Definition in the comprehensive emission standard for atmospheric pollutants: refers to all general terms except methane, mainly including alkane, olefin, aromatic and oxygen-containing components.

Under normal conditions, hydrocarbon substances, except methane, are mostly liquid or solid, and have different vapor pressure according to their molecular weight and structural form. Therefore, as an atmospheric pollutant, it actually refers to hydrocarbon substances with C2 ~ C12.

Hydrocarbons are highly flammable and explosive, and their specific physics depends on their monomer composition and concentration.

Generally believes that the boiling point higher than 260 ℃ the compound rate of volatile emission can be neglected, therefore does not consider at 20 ℃ under the condition of the lower limit of vapor pressure (0.01 kpa) is ok, the various definition of total volatile organic compounds, also can be clear and unified as: melting point is lower than the room temperature and atmospheric pressure boiling point below 260 ℃ under all volatile organic compounds.

In summary, total volatile organic compounds (TVOCs) and non-methane total hydrocarbons (NmHc) are two different concepts, but are consistent in most cases, and total volatile organic compounds cover a greater range than non-methane total hydrocarbons.

发布于2017-11-27