For motor gasoline, what does a higher vapour pressure (all else equal) most directly imply about operational and storage behavior?

Introduction:
Vapour pressure is a key volatility parameter for gasoline, affecting safety, evaporative emissions, drivability, and storage losses. Understanding its implications helps refiners set seasonal Reid Vapour Pressure (RVP) targets and terminal operators manage losses and safety margins.

Given Data / Assumptions:

• We compare gasolines differing primarily in vapour pressure.
• Storage conditions are typical atmospheric tanks with fixed or floating roofs.
• Flash point trends inversely with volatility for highly volatile fuels.

Concept / Approach:
Higher vapour pressure indicates a greater tendency to form vapor at ambient conditions. This leads to (1) lower flash point because vapours reach flammable concentrations at lower temperatures, and (2) higher breathing losses because day–night temperature swings cause expansion/contraction cycles, expelling vapor-laden air from tanks.

Step-by-Step Solution:
1) Link higher RVP to increased volatility.2) Infer lower flash point as flammable vapor is achieved more readily.3) Recognize thermal breathing in storage increases vapor displacement losses.

Verification / Alternative check:
Standards regulating summertime RVP (to limit smog-forming VOCs) implicitly acknowledge the correlation between volatility and evaporative loss/safety characteristics.

Why Other Options Are Wrong:
“Neither” or “lower emissions” contradict fundamental volatility behavior.Choosing only one effect (a or b) ignores the dual impact on flash point and tank losses.

Common Pitfalls:
Equating RVP solely with cold-start quality while ignoring storage emissions and safety ramifications; both operational domains matter in fuel formulation and logistics.

Final Answer:
Both (a) and (b)