Final answer:
Compressed air usually has water and compressor oil, which can be harmful to human health, the environment, and the compressor itself.
Step-by-step explanation:
Compressed air often contains moisture and compressor oil which can be detrimental to human health, the environment, and the compressor equipment itself. When inhaled, the oil and moisture can be harmful to human lungs and overall health. For the environment, these contaminants can contribute to pollution and degrade the quality of air. Additionally, moisture and oil can cause damage and wear to the compressor over time, potentially leading to malfunction or decreased efficiency.