【Daily Question】Production, Storage, and Transportation Exchange - 9.20

**The specified limit for noise exposure in the workplace over an 8-hour period is (A) decibels. A. 85 ； B. 88 ； C. 103. The exposure limit is 85 decibels for an 8-hour daily exposure time, 88 decibels for 4 hours, 91 decibels for 2 hours, and 94 decibels for 1 hour. These values are based on the \"Health Standards for Noise in Industrial Enterprises\" established by the Ministry of Health and the General Administration of Labor; the noise-related standards set out in the 2007 \"Occupational Health Standards of the People’s Republic of China\" also serve as a reference. I. Approaches to noise control In China, relevant standards stipulate that noise levels in residential areas should not exceed 55 decibels during the day, and should be below 45 decibels at night. Some cities around the world have introduced restrictions on the noise generated by transportation. To prevent noise, Professor Ma Dayou, a renowned acoustician in our country, summarized and studied the hazards and standards related to various types of noise existing both domestically and internationally, and proposed three recommendations: ① To protect people’s hearing and health, the allowable level for noise should be between 75 and 90 decibels. ②To ensure smooth conversation and communication, the allowable level of environmental noise is 45–60 decibels. ③It is recommended that the sleep noise level be between 35 and 50 decibels. Additional note: ① 30–40 decibels is an ideal quiet environment. ②70 decibels can affect conversations. ③Living in an environment with noise levels above 90 decibels for a long time can severely damage hearing and lead to conditions such as neurasthenia, headaches, and high blood pressure. ④If suddenly exposed to noise as loud as 150 decibels, in mild cases the eardrums may rupture and bleed, resulting in complete loss of hearing in both ears ； In severe cases, it can trigger cardiac resonance, leading to death.