Radonkonsentrasjonen måles ved målepunktet.

Because Norwegian usually forms compound nouns as one single word, much more often than English does.

So:

• radon = radon
• konsentrasjon = concentration
• radonkonsentrasjon = radon concentration

Then the definite ending is added:

• radonkonsentrasjon = radon concentration
• radonkonsentrasjonen = the radon concentration

This is very common in Norwegian. English often uses two words where Norwegian prefers one compound word.

The ending -en marks the noun as definite singular for an en-word.

Here is the pattern:

• en konsentrasjon = a concentration
• konsentrasjonen = the concentration

The whole compound follows the gender of its final part, which is konsentrasjon. Since konsentrasjon is an en-word, the compound becomes:

• en radonkonsentrasjon
• radonkonsentrasjonen

So the -en is basically the Norwegian way of expressing the.

Because in Norwegian, the definite article is often attached to the end of the noun instead of appearing as a separate word.

Compare:

• English: the concentration
• Norwegian: konsentrasjonen

That is normal Norwegian structure.

You only get an extra definite word like den/det/de in certain situations, especially with adjectives:

• konsentrasjonen = the concentration
• den høye konsentrasjonen = the high concentration

But in your sentence, there is no adjective, so the ending alone is enough.

Måles is the present passive form of måle.

• å måle = to measure
• måler = measures / is measuring
• måles = is measured / gets measured

So:

• Vi måler radonkonsentrasjonen. = We measure the radon concentration.
• Radonkonsentrasjonen måles ... = The radon concentration is measured ...

This -s passive is very common in Norwegian, especially in formal, technical, and written language.

Yes, in this sentence that is the natural equivalent.

Norwegian has a common passive form made by adding -s to the verb:

• måle → måles

English usually uses:

• is measured

Norwegian can also form the passive with bli + past participle in some contexts, but here the -s passive is the normal compact way to say it.

So måles is not a different tense here; it is simply the passive form in the present.

Ved often means at, by, or near, depending on context.

In this sentence, ved målepunktet means something like:

• at the measuring point
• at the measurement point

It indicates the location where the measuring is done.

A learner may expect på or i, but ved is very natural when referring to a specific point, position, or spot.

Because målepunkt is a compound whose last part is punkt, and punkt is a neuter noun (et punkt).

In Norwegian compounds, the last element decides the gender.

So:

• et punkt = a point
• punktet = the point

And therefore:

• et målepunkt = a measuring point / measurement point
• målepunktet = the measuring point / measurement point

That is why you get -et here, while radonkonsentrasjonen takes -en.

It is another compound noun:

• måle = measure / measuring
• punkt = point

Together:

• målepunkt = measuring point / measurement point

This is a very typical Norwegian compound. English might use either:

• measurement point
• measuring point
• sometimes simply the point of measurement, depending on context

Norwegian usually just builds the concept into one noun.

It is in the present tense, but in a sentence like this it often expresses a general procedure, technical statement, or standard fact, not necessarily something happening at this exact moment.

So måles can mean:

• is measured
• gets measured
• is measured as a rule / in the procedure

Technical Norwegian often uses the present tense this way.

Yes, but Norwegian still follows the V2 rule in main clauses: the finite verb usually stays in the second position.

The normal order here is:

• Radonkonsentrasjonen måles ved målepunktet.

But you could also move the location to the front:

• Ved målepunktet måles radonkonsentrasjonen.

That is also correct. When ved målepunktet comes first, the verb måles must still stay in second position.

So you cannot say:

• Ved målepunktet radonkonsentrasjonen måles. ❌

The subject is radonkonsentrasjonen.

Even though the verb is passive, the thing being talked about grammatically is still the subject:

• Radonkonsentrasjonen = subject
• måles = verb
• ved målepunktet = adverbial phrase of place

In English, this is exactly like:

• The radon concentration is measured at the measurement point.

Because Norwegian does not capitalize ordinary nouns.

So:

• radon
• konsentrasjon
• målepunkt

all stay lowercase unless they begin the sentence or are part of a proper name.

This is different from German, but the same as English in that respect.