Here's the breakdown:

* Air masses DO form near the equator. This is because the equator receives the most direct sunlight, leading to warm, moist air rising.

* These air masses ARE tropical. Tropical air masses are characterized by their warm temperatures and high humidity.

* However, not ALL air masses near the equator are tropical. Some might be maritime equatorial air masses, which form over the ocean and are even more humid than typical tropical air masses.

So, while it's generally true that air masses near the equator are tropical, it's important to remember that there are specific subtypes like maritime equatorial.