“一坐高铁就犯困”，铁路专家回应网传高铁二氧化碳超标：未超标准限值2500ppm

Core Viewpoint - The article addresses concerns regarding the carbon dioxide (CO2) levels in high-speed trains, clarifying that the reported levels do not exceed the established safety standards [1] Group 1: CO2 Standards and Regulations - The standard limit for CO2 concentration in passenger trains in China is set at a maximum of 2500 ppm according to TB/T 3493-2017, which is specific to rail vehicles [1] - In Europe, the standard limit for CO2 concentration in passenger trains is 5000 ppm as per EN13129-2016 [1] - The reported passenger measurements referenced a standard from GB 50736-2012, which is applicable to civil buildings and not to passenger trains [1] Group 2: Air Quality Management in Trains - High-speed trains are designed with a fully sealed car body, and air exchange is managed entirely by the air conditioning system, providing a fresh air volume of over 15 m³/h per person [1] - The air exchange rate in these trains ranges from 6 to 12 times per hour, ensuring that CO2 levels typically do not exceed 1500 ppm during normal operation [1] - During transit through continuous tunnel sections, the train implements pressure protection measures that temporarily restrict air exchange with the outside, which may lead to a short-term increase in CO2 levels, but this is not harmful to passenger health [1]