There is no way to increase the height of the particle field, but you could add passengers to make it look like you increased the height.
By adding passengers you get a longer command and it is needed to be run from a command block.
This works fine But the code gets messy...
This is the code with one passenger added:
/summon area_effect_cloud ~ ~ ~
{Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}
This will make the particle field 2 high.
By adding more passengers you can make it taller, but you need to add the passengers to the already existing passengers, this is what makes the code messy.
This is how it would look like with 3 passengers, so a total of 4 fields:
/summon area_effect_cloud ~ ~ ~
{Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}
Here is also an image:
You can continue like this and get results like:
Or like this:
But this is what the code looks like for the last image:
/summon area_effect_cloud ~ ~ ~
{Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Passengers:[{id:"minecraft:area_effect_cloud",Particle:"dust 1.000 1.000 1.000 1",Radius:4.5f,Duration:200,
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}],
Effects:[{Id:2b,Amplifier:2b,Duration:20}]}
This is definitely not difficult if you use sites like MCStacker. I just create one command, then I copy it, create a passenger and paste for as many layers as you would need.
That makes it a lot easier than going through the command manually.
But you do need to add the passengers to the already existing passengers, if you just add more passengers to the first area_effect_cloud then there would just be more than one area_effect_cloud on the 2:nd layer.