The young man named Xiao Li immediately fumbled in a fluster when he heard this, hurriedly pulling a portable air quality detector from the backpack he carried.
With several beeps, the air quality detector started up, and the intake on top began drawing in and filtering the surrounding air.
The operating principle of this type of air quality detector was to draw in a fixed volume of air over a set period, then determine the cleanliness of the entire working environment from the number of particles detected.
Yet shortly after switching on the device, the young man named Xiao Li went from frowning to looking puzzled, and finally to utter astonishment.
"D-Director, the environmental cleanliness has surpassed Class 1!" Xiao Li swallowed, his voice trembling slightly.
Class 1 cleanliness alone would have been fine, because such environmental standards could be found in the sterile operating rooms of many hospitals and in semiconductor factories.
What was Class 1 cleanliness?
It meant that within one cubic meter of space, there were no more than ten floating particles measuring 0.1 micrometers in diameter!
Under current international standards, cleanliness was divided into nine classes. With each improvement in class, the number and diameter of particles progressively decreased, and Class 1 cleanliness was the highest standard in the entire industry.
This degree of cleanliness was already almost sterile and dust-free.
Yet according to the instrument's LCD screen, not even a single particle had been detected in the air of this underground facility.
Such astonishing air quality was beyond even the most advanced foreign chip manufacturers.
That was because anywhere people entered or left was liable to acquire suspended particles, from water molecules carried out through breathing to dust, as well as bacteria, fungi, and so on clinging to the human body.
To address this human-borne