ISO 17299-2 mainly measures odorous gases such as ammonia, acetic acid, methyl mercaptan and hydrogen sulfide.

ISO 17299-3 mainly measures odorous gases such as indole, isovaleric acid, nonenal and acetic acid with added sodium chloride (NaCl).

The application scenarios of these odorous gases in textiles are as follows:
- **Ammonia**: Mainly derived from the decomposition of human sweat and excrement. It is more common in close-fitting textiles such as sportswear, socks, and underwear. After the human body sweats, the components in the sweat are decomposed by bacteria to produce ammonia. Especially after exercise, the body sweats more. If the air permeability and moisture absorption of the textile are not good, the odor of ammonia and other odors will be more obvious. In addition, in some textiles such as diapers and diapers for infants and young children, ammonia odor is also easy to produce due to contact with excrement.
- **Acetic acid**: It is usually produced by the decomposition of components in sweat by microorganisms. Commonly found in all kinds of underwear, such as T-shirts, underwear, etc., especially in summer or high temperature environments, the amount of sweating increases, and substances such as fatty acid esters in sweat are decomposed by microorganisms, which will produce acetic acid, causing the clothes to have a sour smell.
- **Methyl mercaptan**: It has a typical smell of rotten eggs or rotten vegetables, which mainly comes from pollutants in the environment and human metabolites. Some outdoor textiles, such as outdoor backpacks and tents, may be exposed to pollutants containing methyl mercaptan in the outside world, thereby absorbing this odor. In addition, in protective clothing for some special work occasions, if there is methyl mercaptan gas in the working environment, its deodorization performance also needs to be considered.
- **Hydrogen sulfide**: It also has a rotten egg smell, which mainly comes from industrial waste gas, sewage, etc. in the environment, and may also be produced in small amounts during the decomposition of human sweat. For some textiles that are often used near industrial environments, such as work clothes, they may be exposed to hydrogen sulfide gas. In addition, the protective clothing of workers in some sewage treatment plants, garbage disposal sites and other places also needs to pay attention to the deodorization performance of hydrogen sulfide.
- **Indole**: It has a fecal odor, which is mainly related to human excrement and microbial decomposition. It may appear in textiles such as adult incontinence products and infant diapers. These products will directly contact excrement. If the deodorizing performance is poor, it will produce obvious indole odor.
- **Isovaleric acid**: It is often present in sweat and is one of the main components that cause human sweat odor. It is more common in textiles such as sportswear and underwear. Especially after long-term exercise or heavy sweating, the smell of isovaleric acid will be more prominent, affecting the wearing experience.
- **Nonenal**: It is mainly produced by the oxidation and decomposition of fat on the surface of human skin and is one of the important components that produce body odor. It is common in daily underwear such as shirts and underwear. Especially for some people with more developed sweat glands, nonenal odor is more likely to be produced on clothes.