It’s illegal to fart? You really don’t believe it-
In 2011, the Attorney General of African country Malawi, George Chaponda, announced that he would make farting in public illegal under the Air Pollution Act. There was a great deal of excitement.
Subsequently, the Minister withdrew his remarks under pressure from public opinion 
Fart is considered to be a kind of gas that is difficult to get into the hall of elegance and is excluded everywhere. < < Shuowen Jiezi > > There are [excrement] and [urine] but there is no [fart].
It was not until the development of manned space technology that astronauts’ farts were especially intrusive in low-pressure enclosed spacecraft.  Scientists had to carry out a series of studies on farts, and we were able to talk about this stinky farts here today.
What is what?
Our digestive tract is really mixed with good and evil people, with water, slag and gas.
This gas is discharged from the anus and becomes fart.
Where does the gas come from?
- One is that we swallow some air more or less when eating, drinking and swallowing saliva. The other is that food undergoes various complicated chemical reactions during digestion to generate gases. The third is that undigested food residues are fermented and decomposed by intestinal bacteria. 
When it comes to farts, everyone unconsciously covers his nose and mouth. In fact, more than 99% of the components of farts are innocent. The victims are nitrogen, oxygen, carbon dioxide, hydrogen and methane, all colorless and odorless gases.
It is worth mentioning that hydrogen and methane are combustible gases. Some obese, constipated and bowel patients have high levels of hydrogen and methane in their farts, and their farts are likely to be ignited. 
The culprits that make fart notorious are indole, methylindole, ammonia, volatile short-chain fatty acids and sulfides, which account for less than 1%.
Among them, hydrogen sulfide, dimethyl sulfide and methyl mercaptan in sulfide are the most heinous crimes.
Sulfide comes from the decomposition of sulfur-containing amino acids in intestinal tract. Sulfur-containing amino acids in meat, poultry, eggs, animal viscera, cheese, onion, cauliflower and other foods are considerable. 
Therefore, it makes sense to say that the more meat you eat, the more smelly your farts will be.
Normal people fart 8 ~ 20 times a day, and the total amount of fart released is about 470 ~ 1500 ml. The amount of fart depends on eating habits and distribution of intestinal flora, especially the former.
Foods that produce more gas include beans, onions, garlic, leeks, radishes, sweet potatoes, potatoes, cashew nuts and oats. They contain a large amount of complex oligosaccharides, which have survived the heavy tempering of the upper digestive tract and still stand firm. Eventually, they are decomposed by intestinal colonization bacteria in the lower segment of the small intestine and colon, and their souls turn into smelly farts and leave without injustice. [2, 4]
Why do some farts sound and some farts do not sound?
When one is alone, the louder the fart, the better it feels. When a group of people, they wish to install a silencer on their buttocks to hide the embarrassment of a fart sound in silence. If only one could control the sound of fart at will.
Fart noise is mainly caused by the vibration of the anal sphincter when the fart passes through the anus. For obese people, the two pieces of meat crowded together will also vibrate and sound when the fart passes through. The faster the flow rate of the fart, the more tense the anal sphincter, and the tighter the two pieces of meat on the buttocks (the fatter the person), the louder the fart sound. 
There are three ways to control fart noise.
- One is to eat less gas-producing food, Fart less nature can’t lift much waves. The second is to adjust posture, Let the buttocks pout, The two sides naturally separate, You can open a passage for the fart. The third is a unique trick. When you blow with your mouth, you can hear the obvious sound of blowing. If you tighten your lips, you can’t make a loud sound even if you blow hard. Similarly, when the anal sphincter is relaxed, it is easy to vibrate and sound. As long as you keep the sphincter tense when farting, the fart sound can be greatly reduced.
As long as you master these three moves skillfully, you can [sneak into the night with the wind and moisten things silently].
Can farts be excreted by hiccups?
Some people say that both the upper and lower parts of the digestive tract can exhaust, if you accidentally release your fart from your mouth when hiccupping.
No, no, no.
Hiccups are caused by stimulating contraction of the diaphragm, Squeeze the stomach wall, A large amount of gas accumulated in the stomach comes out of the mouth along the esophagus. Once the gas enters the intestinal tract, It is very difficult to ascend. The intestinal tract is constantly contracting at the proximal end and relaxing at the distal end, forming a continuous fluctuation, pushing the contents to the anus. This is an irresistible force. No matter how willful the gas is, it cannot openly retrograde (except intestinal obstruction). 
Therefore, there is generally no such embarrassing thing as fart coming out of the mouth.
Is it good for gastrointestinal tract to fart more?
Fart is excellent and can relieve the traffic pressure in gastrointestinal tract. However, deliberately farting in order to fart is really a combination of eggs.
Fart, like defecation and urine, belongs to human excrement. The existence value of excrement is excretion, which is harmful and useless to stay in the body.
A large amount of gas accumulation in the intestinal tract will affect the contraction function of the intestinal tract, making people feel abdominal distension and chest tightness. Indole, ammonia, hydrogen sulfide and other odors will be slowly absorbed into the blood by the intestinal mucosa, causing discomfort such as listlessness, dyspepsia, dizziness and the like. 
Therefore, [if you don’t let go of your fart, you will suffer internal injuries].
For the sake of your own body, please be sure to find a place where no one can fart seriously.
1. CHIBEWA, J. Chaponda: Oops I goofed, you can fart! . Marevi Post. 2011-03-02.
2. Gas in the Digital Tract-National Digital Diseases Information Clearinghouse. Http://www.niddk.nih.gov.
3. Suarez, F.; Furne, J; J Springfield; Levitt, M. Insights into human colonic physiology obtained from the study of flatus composition. The American Journal of Physiology, 1997, 272 (5 Pt 1): G1028-33.
4. Azpiroz, F. Intestinal gas dynamics: mechanisms and clinical relevance. Gut, 2005, 54 (7): 893-895.
5. Staudacher, HM; Whelan, K.; Irving, PM; Lomer, MC. Comparison of symptom response following advice for a diet low in fermentable carbohydrates (FODMAPs) versus standard dietary advice in patients with irritable bowel syndrome. Journal of human nutrition and dietetics: the official journal of the British Dietetic Association, 2011, 24 (5): 487-95.
6. Ohge, H.; Furne, JK; J Springfield; Sueda, T.; Madoff, RD; Levitt, MD. The effect of antibiotics and bismuth on fecal hydrogen sulfide and sulfate-reducing bacteria in the rat. FEMS microbiology letters, 2003, 228 (1): 137-42.
7. The 2001 Ig Nobel Prize Winners. Http://www.improb.com.
8. Pimentel, Mark; Robert P Gunsalus; Satish SC Rao; Husen Zhang. Methanogens in Human Health and Disease “. The American Journal of Gastroenterology Supplements, 2012, 1 (1): 28-33.
Responsible Editor: Ji Lingyan