Given below are two statements:

Statement I: Volatile Organic Compounds (VOCs) are emitted from vehicles.

Statement II: Volatile Organic Compounds are emitted from some tree

In the of the above statements, choose the answer from the options given below

The correct answer is Both Statement I and Statement II are true.

Let us analyze each statement carefully and understand why both of them are scientifically accurate.

Understanding Volatile Organic Compounds (VOCs):
Volatile Organic Compounds (VOCs) are a broad category of carbon-containing chemical compounds that easily evaporate at room temperature due to their high vapour pressure and low boiling points. They are released into the atmosphere from both anthropogenic (human-made) and biogenic (natural/biological) sources. Once in the atmosphere, VOCs react with nitrogen oxides (NO_x) in the presence of sunlight to form ground-level ozone and secondary pollutants, contributing to smog and air quality deterioration.

Evaluating Statement I — VOCs are emitted from vehicles:
This statement is TRUE. Vehicles powered by internal combustion engines (petrol or diesel) are one of the most significant anthropogenic sources of VOC emissions. The following processes in vehicles release VOCs into the atmosphere:

• Incomplete combustion of fuel: When fuel is not completely burned in the engine, unburned hydrocarbons — which are VOCs — are released through the exhaust pipe.
• Fuel evaporation: Petrol itself is a highly volatile mixture of hydrocarbons. VOCs evaporate from fuel tanks, carburettors, and fuel lines, especially in hot conditions.
• Exhaust emissions: The exhaust gases from vehicles contain compounds such as benzene, toluene, ethylbenzene, and xylene (collectively known as BTEX), all of which are classified as VOCs and are known to be harmful to human health.

Therefore, motor vehicles — particularly those running on fossil fuels — are a well-established and major source of VOC pollution in urban environments. Statement I is unambiguously correct.

Evaluating Statement II — VOCs are emitted from some trees:
This statement is also TRUE. Many plant species, particularly trees, naturally produce and release VOCs as part of their biological processes. These are called Biogenic VOCs (BVOCs). Key examples include:

• Isoprene (C₅H₈): Emitted in large quantities by trees such as oaks, poplars, and eucalyptus. Isoprene is the single most abundantly emitted biogenic VOC globally. It is believed to help plants cope with heat stress.
• Monoterpenes and Sesquiterpenes: Emitted by coniferous trees like pine, spruce, and fir. These are responsible for the characteristic "forest smell" and are also reactive VOCs that contribute to aerosol formation.
• Methanol and Acetaldehyde: Also released by vegetation during normal metabolic activities.

In fact, it is estimated that biogenic sources contribute far more VOCs to the global atmosphere than anthropogenic sources. The interaction of these naturally emitted VOCs with human-produced pollutants (like NO_x) can worsen air quality, especially in and around forested urban areas. Statement II is therefore completely correct.

Final Conclusion:
Since Statement I is true (vehicles emit VOCs through exhaust and fuel evaporation) and Statement II is also true (many trees naturally emit biogenic VOCs such as isoprene and terpenes), the correct answer is confirmed to be "Both Statement I and Statement II are true."