Which of these fuels is an effective measure to control air pollution?

Options

A. Unleaded petrol
B. Natural gas
C. Wood
D. Coal

Explanation

To determine which fuel is an effective measure to control air pollution, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Options**: We have four fuels to consider: unleaded petrol, natural gas, wood, and coal. We need to evaluate each one based on their emissions and impact on air quality.

2. **Analyzing Unleaded Petrol**:
- Unleaded petrol is better than leaded petrol because it does not contain lead, which is a harmful pollutant.
- However, it is still a fossil fuel and produces carbon dioxide (CO2) when combusted.
- Incomplete combustion can lead to carbon monoxide (CO) emissions, which are dangerous, as well as oxides of sulfur and nitrogen, contributing to acid rain.
- **Conclusion**: Unleaded petrol is not an effective measure to control air pollution.

3. **Analyzing Natural Gas**:
- Natural gas is primarily methane (CH4).
- When combusted, it mainly produces carbon dioxide and does not produce harmful oxides like sulfur or nitrogen.
- It has a low risk of producing carbon monoxide.
- **Conclusion**: Natural gas is an effective measure to control air pollution.

4. **Analyzing Wood**:
- The combustion of wood releases a significant amount of carbon monoxide and particulate matter.
- It also emits nitrogen and sulfur oxides, which can contribute to air pollution and respiratory issues.
- **Conclusion**: Wood is not an effective measure to control air pollution.

5. **Analyzing Coal**:
- Coal is another fossil fuel that releases sulfur and nitrogen oxides upon combustion.
- It contributes significantly to air pollution and is associated with various environmental issues.
- **Conclusion**: Coal is not an effective measure to control air pollution.

6. **Final Decision**:
- After analyzing all options, the only fuel that stands out as an effective measure to control air pollution is **natural gas**.

### Final Answer:
**Natural gas is the effective measure to control air pollution.**

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