is not all equipment today low emission marked?

Since many year we have had the "low emission" marks on the monitors that are sold in europe. Our Swedish "MPR" and "TCO" low emission marks are today seen in the whole world.
The latest "low emission" standard demands maximun 1V/m RMS in Band 2 (2-400kHz) in a point 30cm right infront of the screen

Is it not enough to buy a "low emission" monitor?

For most it is enough to buy a computer and monitor if the shelf.
For some it just doesn´t work. Many feel a burning sensation in the skin. Others feel dizzy and affected in other ways in front of a normal monitor.

What is the difference between a "low emission" monitor a screened monitor?

All "low emission" standards today only considers RMS, the 
average measure.

All know that in Sweden we have a quite neutral average temperature over a year. But still we know that some days the temperature drops to minus 20 degrees celcius and some days we have freezing cold minus 30 degrees celcuis.
To dress everyday for the average temperature would mean that some days we would freeze and some days it would be far to warm.

So even if you have low RMS, average V/m, the equipment might have extreme short pulses of electric fields.

Screened equipment is also screened for these highfrequency electric fields.

What about LED screens?

The backlight in a LCD/LED screen is small Light Emitting Diods. These are very energy efficient and give small amounts of electric fields if they are powered by DC, dead current. In a screen and also in normal homelights the LEDs are powered by pulsating DC and that creates almost the same emissions as old fashioned TFT screens.
From a older LCD / TFT screen we often measure fields in the span 30000 - 45000Hz. On a LCD / LED screen we often measure fields in the span 40000 - 68000Hz. 

Typical difference between a normal 22" LED monitor with plastic chassie, a 24" monitor with metal chassie and and a fully shileded screen amak 24"