The green, through photosynthesis, absorbs carbon dioxide and exhales oxygen which is essential for humans. Moreover, plants naturally have the function of purifying the air. This oxygen generator takes advantage of these characteristics of green plants. Place a pot with green plants on it and water them. Excess water will be evaporated, accelerating the photosynthesis of plants, thus producing more oxygen. Besides, we don't have to worry about when the plants need water.