He looketh on the earth, and it trembleth: he toucheth the hills, and they smoke.
Psalm 104:32 KJV
God describes the life of an ungodly man as smoke:
I have spread out my hands all the day unto a rebellious people, which walketh in a way that was not good, after their own thoughts; [5] Which say, Stand by thyself, come not near to me; for I am holier than thou. These are a smoke in my nose, a fire that burneth all the day.
Isaiah 65:2,5 KJV
It’s clear from the description that their life is an unpleasant smoke 💀 to him. On the other hand, those who have given their lives as a living sacrifice ✝️, the smoke of their burning is a pleasant smell to God:
And walk in love, as Christ also hath loved us, and hath given himself for us an offering and a sacrifice to God for a sweetsmelling savour.
Ephesians 5:2 KJV
This is what the psalmist is describing when he says that the LORD looks on the earth and it trembles and touches the hills and they smoke, it’s the converted life.
The earthen man who now lives in awe (trembles) of God. Just as the mountain burned with fire when it came in contact with the presence of God (Duet 4:11), so to the man touched by the LORD will burn as a sweet smelling savour.
This is the fire of God’s Spirit, with fervent heat, burning up all the works of the flesh in earthen man. This is the sweet savour he loves.
For we are unto God a sweet savour of Christ, in them that are saved, and in them that perish:
2 Corinthians 2:15 KJV