Which of the following are major gaseous pollutants present in the troposphere?
I`H_2S`
IIOxides of sulphur
III nitrogen and carbon
IV `O_3`

Options

A. I and II
B. I and III
C. I,II and III
D. All of these

Answer

To determine the major gaseous pollutants present in the troposphere, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding the Troposphere**:
- The troposphere is the lowest layer of Earth's atmosphere, extending from the surface up to about 10 km. It is where most weather events occur and is essential for life.

2. **Identifying Gaseous Pollutants**:
- We need to identify which of the given options are recognized as major gaseous pollutants in the troposphere.

3. **Analyzing Each Option**:
- **Option I: H₂S (Hydrogen Sulfide)**:
- H₂S is a colorless gas with a characteristic odor of rotten eggs. It is indeed a pollutant and can be found in the troposphere, especially near industrial areas or natural sources like volcanic eruptions.
- **Option II: Oxides of Sulfur**:
- Sulfur oxides (SO₂ and SO₃) are significant pollutants that result from burning fossil fuels and industrial processes. They are present in the troposphere and contribute to acid rain.
- **Option III: Nitrogen and Carbon Oxides**:
- Nitrogen oxides (NO and NO₂) and carbon oxides (CO and CO₂) are common pollutants from vehicle emissions and industrial activities. They are prevalent in the troposphere and are major contributors to air pollution.
- **Option IV: O₃ (Ozone)**:
- Ozone (O₃) is primarily found in the stratosphere, where it forms the ozone layer. While ground-level ozone can be a pollutant, it is not considered a major pollutant in the troposphere when compared to the others listed.

4. **Conclusion**:
- The major gaseous pollutants present in the troposphere are:
- I. H₂S
- II. Oxides of Sulfur
- III. Nitrogen and Carbon Oxides
- Therefore, the correct answer is options I, II, and III.

### Final Answer:
The major gaseous pollutants present in the troposphere are:
- I. H₂S
- II. Oxides of Sulfur
- III. Nitrogen and Carbon Oxides