The formation of photochemical smog depends upon

Options

A. CO
B. NO
C. `CO_(2)`
D. `SO_(2)`

Answer

To answer the question regarding the formation of photochemical smog, we need to analyze the components that contribute to its formation. Here’s a step-by-step breakdown:

### Step 1: Understanding Photochemical Smog
Photochemical smog is a type of air pollution that results from the interaction of sunlight with pollutants in the atmosphere. It is primarily characterized by the presence of ozone at ground level, which is harmful to human health and the environment.

**Hint:** Consider the role of sunlight in the formation of smog.

### Step 2: Identifying Primary Pollutants
The formation of photochemical smog depends on primary pollutants. These include:
- Nitric oxide (NO)
- Nitrogen dioxide (NO2)
- Volatile organic compounds (VOCs)
- Carbon monoxide (CO)

**Hint:** Think about which pollutants are directly emitted into the atmosphere and their sources.

### Step 3: Recognizing the Role of Secondary Pollutants
In addition to primary pollutants, secondary pollutants are formed through chemical reactions in the atmosphere. Ozone (O3) is a significant secondary pollutant that forms when sunlight reacts with primary pollutants like NO and VOCs.

**Hint:** Remember that secondary pollutants are not directly emitted but are formed from reactions involving primary pollutants.

### Step 4: Analyzing the Given Options
From the options provided:
- Carbon monoxide (CO) is primarily associated with acid rain and global warming.
- Nitric oxide (NO) is a primary pollutant that contributes to the formation of photochemical smog.
- Carbon dioxide (CO2) is also linked to global warming and acid rain.
- Sulfur dioxide (SO2) is mainly responsible for acid rain.

**Hint:** Focus on which option is directly related to the formation of photochemical smog.

### Step 5: Conclusion
The formation of photochemical smog primarily depends on nitric oxide (NO) as it is a key primary pollutant that reacts in the presence of sunlight to form ozone and other components of smog.

**Final Answer:** The formation of photochemical smog depends upon nitric oxide (NO).