Is hydrogen ventilator safe and dangerous?

The explosion limit of hydrogen is 4.0% ~ 75.6% (volume concentration), that is to say, if the volume concentration of hydrogen in the air is between 4.0% ~ 75.6%, it will explode when it meets a fire source, but when the hydrogen concentration is less than 4.0% or more than 75.6%, it will not explode even when it meets a fire source. The hydrogen concentration of hydrogen is up to 99%. It is not artificially mixed with air. Hydrogen respirator and hydrogen water cup are safe. Moreover, the molecular weight of hydrogen is the smallest of all substances, and its diffusivity is very good. Do not worry about the safety of hydrogen products such as hydrogen-rich water cups.