Masks are a kind of sanitary products. Generally, they are worn on the mouth and nose to filter the air entering the mouth and nose to block harmful gases, odors, droplets, viruses and other substances. They are made of gauze or paper. Disposable Face Mask,Non-Woven Face Mask,Medical Surgical Mask Shandong Kangshun Daily Products Co., Ltd , https://www.centurybenifit.com
Masks have a certain filtering effect on the air entering the lungs. When respiratory infectious diseases are prevalent, when working in dust and other polluted environments, wearing masks has a very good effect.
In spring, when the temperature rises, the metabolism of fish increases, the activity increases, and the oxygen consumption increases, and “drifting heads†can easily occur. Because this "floating head" occurs in the spring when the water temperature is low and it is not easily noticed, it is called a "drifting head." Symptoms are that the fish floats on the top of the water. From time to time, the mouth stretches out to the surface to soak up the air. Severe suffocation can cause death. The main reasons for the "drifting head" of spring fish are as follows: The fish species has a high density, and it has not divided the pond in time, causing an oxygen-depleted floating head. Fish ponds have been unclear for many years, wild fish and other over-proliferation, and competition for oxygen with farmed fish, resulting in anoxic "floating head" of farmed fish. Water quality that is too fat or too thin can cause the fish to lack oxygen "floating head." Farmers do not control the feeding and feed too much. Too much organic matter at the bottom of the pond, low pH, decomposition of organic matter produces large amounts of ammonia and hydrogen sulfide, causing fish poisoning "floating head."