It was autumn. The ginkgo leaves on the campus were turning yellow. With the background of blue sky and white clouds, they fell down like a butterfly dancing in the air. The trace of heat and humid left by the summer was disappearing and the weather was getting cold. It was getting dry. David's dad bought a new humidifier, in which essential oils of different favors could be used. When David came home, he put away his schoolbag first and put on slippers. Then, he opened the humidifier. As the fragrant mist blew on his face in a comfortable way, he felt relaxed and pleasant.
At the weekend, David suddenly felt that his throat didn't feel well, and he coughed now and then. His mom was worried about him and asked, "It's autumn now. Do you catch cold when you went running in PE lesson?" He shook his head and replied, "I don't think so. The PE lesson was delayed until next week because of a math quiz this week." After thinking for a while, his dad said, "I saw a report a few days ago. I'm thinking if the humidifier is to blame." David asked confusingly, "Does the humidifier make people sick?"
Mom continued immediately, "You have reminded me! I noticed a health tip. If a humidifier is used for a long time without cleaning and sterilization, its inner wall will breed bacteria. If there are pathogenic bacteria, they will enter into respiratory tract and lungs through the tiny droplets sprayed from the humidifier. These water droplets with pathogenic bacteria may cause allergic pneumonia."
David asked curiously, "But the air is not 100% clean. Why using humidifier makes people ill?"
His dad explained patiently, "Since you talked about the air, let's start with its humidity. Generally speaking, a humidity of 40% to 70% is suitable for human body. When the humidity in the air remains at 45% to 65%, it's hard for the germs to spread. Autumn has arrived, the air is dry. Dry lips begin to peel. When the humidity is lower than 30%, we should turn on the humidifier. However, when the humidity is over 80%, it is easy to breed bacteria, dust mites and molds. You will feel sultry, and there will be condensation on the wall, the floor and the table. At this time, we should turn off the humidifier and open the window to ventilate, or what we just said will happen."
Mom added, "So, we should put the humidifier away, and not let it blow on our face. If the droplets sprayed from the humidifier have germs, they will enter respiratory tract easily. In a general way, we should shut it down when it was turned on for two hours."
Then mom turned to dad and said, "Generally speaking, it is not recommended to add other things in the humidifier. These chemicals may irritate lungs. And water in the humidifier should be changed every day. It should be cleaned on a weekly basis."
Author: Lu An
京公网安备11010502039775号
