Is rainwater considered pure water?

• A. Yes, always
• B. No, it may contain pollutants from the air
• C. Yes, after filtration
• D. No, but only in rural areas

Answer: (B)

Rainwater is not considered pure water because it can contain various pollutants that are present in the atmosphere. As rain forms, it can absorb gases, such as sulfur dioxide and nitrogen oxides, and pick up particulate matter while falling through the air. This means that while rainwater may start as relatively clean, it can become contaminated with these pollutants.

The presence of these substances can lead to the precipitation of acid rain, which can negatively impact the environment, including soil, water bodies, and plant life. Thus, relying on rainwater as pure water without treating it can pose health risks if it is used for drinking or other purposes. Understanding this is crucial for water treatment operators, as they must ensure that all water sources, including rainwater, are properly tested and treated to remove contaminants before use.