carefully, closely, rigorously (esp. BrE), strictly
Television advertising is strictly monitored.

periodically, regularly, routinely, systematically
constantly, continually, continuously
effectively, properly
automatically
remotely
electronically

be able to
We will now be able to monitor its progress more closely.

continue to
The authorities will continue to monitor the situation.

for
The workers are constantly monitored for exposure to radiation.

Monitor is used with these nouns as the subject:
condition, observer, satellite

Monitor is used with these nouns as the object:
activity, call, change, development, effect, effectiveness, election, email, emission, expenditure, health, heartbeat, impact, implementation, level, movement, performance, pollution, progress, progression, quality, radiation, radioactivity, situation, temperature, test, traffic, usage