露點的兩個重要特征:

1. Dewpoint is not temperature dependent parameter 露點溫度與氣體溫度無關

• the measurement is not changed if the gas temperature change 如果氣體溫度變化，露點溫度不變

– process gas can be cooled before measurement 流程氣體通常在測量前冷卻

2. Dewpoint is pressure dependent parameter 露點溫度是與壓力相關的參數

• when pressure increases also dewpoint value increases 壓力升高時露點升高

– in pressurized systems Vaisala recommends to measure in gas pressure, not in ambient pressure 對于帶壓環境，建議帶壓測量露點，不建議采樣常壓測量。