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Chapter 357: 355: Gas Mask
Chapter 357: 355: Gas Mask
Chapter 357: Chapter 355: Gas Mask
The stench of sewage surged like a tidal wave, the rotten, damp rankness shooting straight to the brain, choking one to the point of breathlessness.
“My god, it stinks so bad here! What’s going on? Is this leading directly to the toilets? Just now… hey, what’s wrong with you!?”
Matthew pinched his nose tightly, tears streaming down his face, his question muffled by the stones in his mouth, but when he turned around, his heart sank.
In the pitch-black environment, everyone saw Bi Fang leaning against the wall, continuously retching, his face pale and his eyes bloodshot, while thick saliva dripped unconsciously from his mouth, falling to the ground.
“Hey, hey, hey, are you okay?”
Matthew was so scared he almost jumped, hurrying over to support Bi Fang, which was much more terrifying than vomiting himself. If something happened to Bi Fang now, Matthew would be done for as well.
He was just a small accessory, and Matthew was very aware of that.
“I’m okay, just give me a moment!”
Bi Fang leaned against the wall and slowly sat down on the ground, cutting off a piece of his lower clothing, soaking it in water, and covering his mouth and nose with it made him feel a little better.
To a normal person, the smell was nauseating, but to Bi Fang, it was amplified a hundred times in his nostrils. The mucous membrane in his nose felt scorched, every olfactory cell was wailing in agony—it was practically like facing a stink bomb head-on!
Thinking back to his memory of the smelliest toilets he had visited, and intensifying that odor by dozens of times, was probably how Bi Fang felt right now. The fact that he had made it this far was a testament to his formidable willpower.
After several attempts at catching his breath, Bi Fang’s senses cleared up a bit. The remaining distance was less than a hundred meters, but unless he stopped breathing from now on, he couldn’t go any farther.
But going there and back was a total of two hundred meters, and in between, he had to find the right spot to make the bomb. It definitely couldn’t be done in less than five minutes—especially not while constantly moving for those five minutes.
Hearing that Bi Fang couldn’t do it, Matthew panicked, “What do we do then?”
“Don’t rush, let me think, just think…”
Bi Fang’s mind was still a bit fuzzy. The plan had been perfect, but he had never expected to be stumped by this stretch of sewer. The smell here was just too overwhelming.
“The smell of a normal sewer is unlikely to break the physiological limit of humans. I suspect there might be hydrogen sulfide here, and perhaps methane as well. Super-sized factories are equipped with septic tanks to prevent the accumulation of sewage. Months of abandonment may have resulted in a fault in the gas filtration system here, coupled with the failure of the exhaust fan, causing poor air circulation in the sewer and the level of hydrogen sulfide in the air to far exceed normal standards.”
“Last July, in Busan, a beautiful place, a 19-year-old girl died from hydrogen sulfide poisoning. The 19-year-old student went to a public toilet near a swimming facility and never came out again.”
“Twenty minutes later, her companions sensed something was wrong, rushed into the toilet, and found her collapsed on the floor, unconscious. The stench in the toilet was unbearable, and her companion nearly passed out from the fumes while continuously vomiting during the rescue attempt. The girl did not survive and was declared dead from hydrogen sulfide poisoning.”
“It was also a malfunction in the gas filtering system that had produced a lot of hydrogen sulfide, which was then released from the exhaust vent of the toilet where the girl had her accident. In the cramped toilet, the concentration of hydrogen sulfide reached 1000ppm, which is 60 times higher than the 15ppm safety standard. At high concentrations, hydrogen sulfide can even cause ‘electrocution-like’ deaths within seconds. The poisoning mechanism of cyanide is similar.”
Matthew, standing nearby, was listening with his eyes growing wider and wider, and his breathing became lighter and lighter. He looked around, saw Bi Fang and quickly imitated him, tearing off a piece of cloth from his body, dampening it, and covering his mouth and nose.
“It’s useless,” Bi Fang shook his head. “I covered my mouth and nose to alleviate the irritation. A wet towel is just a fabric of fibers; it can’t block these gas molecules and has no protective effects against poison. If it really could effectively block smoke and poisonous gases, it would also cut off the air supply, making it impossible to breathe.”
[Damn, is it that dangerous? I’ll never go to a public toilet again.]
[Scary, so scary.]
[Old Fang knows too much, like a chemist.]
[Ah, I looked it up! When hydrogen sulfide enters the bloodstream, it quickly finds an oxidized form of cytochrome oxidase and binds with the trivalent iron in the heme. This enzyme’s trivalent iron should be reduced to a divalent iron to form a reduced-type cytochrome oxidase that passes electrons during the redox process, utilizing molecular oxygen.]
[Continued: But hydrogen sulfide steals the trivalent iron, thus blocking the human respiratory chain and causing tissue cells to lack oxygen. Additionally, hydrogen sulfide also has a strong cytotoxic effect on the respiratory system’s lungs, causing severe damage to lung tissues and resulting in pulmonary edema!!!]
Quick-reacting netizens had already started searching on Baidu, finding out the dangers of hydrogen sulfide,
“What do we do now?”
Seeing that a wet towel was useless, Matthew had no idea what to do; he was a photographer and had no clue how to save himself in this situation.
Unexpectedly, Bi Fang waved his hand, signifying to Matthew to stay calm, “Don’t rush. There are often toxic gases in sewers, so I came prepared for such a situation. In case we encounter this, we can make a simple gas mask. Do you remember what I asked you to do before we came down?”
“Are you talking about that charcoal?”
Matthew quickly dropped his backpack, pulling out a big handful of black charcoal particles that Bi Fang had him prepare that morning, but he hadn’t explained why. Now, it was starting to make sense.
Bi Fang took the charcoal from him, explaining, “A gas mask generally consists of four parts: a poison filtration material, a smoke filtration material, an isolation material, and a durable sealing material.”
“What we’re dealing with is toxic gas, so the poison filtration material is essential. In the wild, we only have a few simple options: one is lime soil particles, two is activated carbon, and three is charcoal.”
Bi Fang took out an empty plastic bottle and used a screwdriver to poke small holes at the bottom to serve as the intake holes for the poison filter, then cut an arch on the other end to fit against the face, ensuring it would match a human’s nose and facial shape.
“All three materials are easy to obtain, especially charcoal. However, I’ve processed it a bit to make more effective activated carbon. The preparation of activated carbon is also simple. Just burn wood to create charcoal, then break it into small pieces, put the pieces into a clean nylon net bag, tie the bag closed, and boil it in an acidic solution for over thirty minutes to remove the oily substance.”
Matthew suddenly understood. “No wonder you had me put vinegar in this morning! It’s acetic acid, right?”
“Exactly,” Bi Fang nodded. “Vinegar contains acetic acid, but you can use other acids if you don’t have vinegar: hydrochloric acid, sulfuric acid, even citric acid, which is added to a lot of foods and even some cosmetics; all of these can be used, as can the alkaline sodium carbonate. If you really have nothing at hand, you could even induce vomiting and use stomach acid to boil.”
Bi Fang nodded, placed a sponge at the bottom of the bottle where he had made the holes, followed by sawdust, adding 7cm and compressing it down to 5cm. Then he placed a layer of gauze above it, followed by 3cm of activated carbon, and topped with another sponge.
A simple gas mask was thus completed.
“All we need now is a sealing material for the face mask, a plastic bag will do. Just make sure it’s soft, thick, and transparent, and most importantly, airtight.”
Bi Fang pushed the body of the canister out of the bag, sealed the joints firmly with tape, and added an adjustable strap through the canister before handing it to Matthew.
“The path ahead you must take on your own.”
“Alright… Huh?” Matthew took the gas mask, about to put it on his head, when he heard this and was taken aback, pointing to himself, “Me?”
Bi Fang nodded. “Yes, you. To be frank, my sense of smell is much more developed than the average person. I smell several times what you can, and I can no longer move forward.”
“Also, don’t use antifreeze to ignite an explosion. Just spread it on the ground, and remember not to use an open flame. Use the method I taught you last time, wrapping potassium permanganate and antifreeze with newspaper. The ignition will take about thirty seconds. Once ready, throw it on the ground then run towards me. Be quick, understand?”
Bi Fang’s expression was serious; the presence of hydrogen sulfide had made him change some of his plans.
In sewers, nine out of ten gases are flammable and can explode, which is why he had avoided using an open flame all this time.
Had his flashlight not been a highly sealed military grade one, he might not have used it at all.
The magnitude of an explosion’s force depends on how much explosive material there is. A whole barrel of antifreeze combined with half a barrel of gasoline might attract some attention if it explodes, but the effect would certainly be limited.
But what about all the hydrogen sulfide and methane in the entire sewer system?
If half the street blew up, how many people would that draw over?