Which of these is not an effect of air pollution?

Options

A. Acid rain
B. Eutrophication
C. Haze
D. Global warming

Explanation

To determine which of the options is not an effect of air pollution, we will analyze each option step by step.

### Step 1: Understand Air Pollution
Air pollution refers to the presence of harmful substances in the air, which can have various negative effects on the environment and human health.

### Step 2: Analyze Each Option
1. **Acid Rain**:
- Acid rain occurs when rainwater mixes with pollutants like carbon dioxide (CO2) and sulfur dioxide (SO2) present in the air, leading to the formation of acids (e.g., carbonic acid, sulfuric acid).
- **Conclusion**: Acid rain is a direct effect of air pollution.

2. **Eutrophication**:
- Eutrophication is the excessive growth of plants and algae in water bodies due to the presence of excess nutrients, primarily nitrogen and phosphorus.
- This phenomenon is primarily associated with water pollution rather than air pollution.
- **Conclusion**: Eutrophication is not an effect of air pollution.

3. **Haze**:
- Haze refers to reduced visibility in the air caused by pollutants, dust, and moisture. It is often a result of air pollution.
- **Conclusion**: Haze is an effect of air pollution.

4. **Global Warming**:
- Global warming is the increase in Earth's average temperature due to the accumulation of greenhouse gases like CO2 in the atmosphere, which is a result of air pollution.
- **Conclusion**: Global warming is an effect of air pollution.

### Step 3: Identify the Correct Answer
After analyzing all the options, we find that **eutrophication** is the only phenomenon that is not a direct effect of air pollution. It is primarily related to water pollution.

### Final Answer
**Eutrophication is not an effect of air pollution.**

---