Extent of Earth’s atmosphere (overview): For general environmental engineering purposes, the atmosphere is considered to form a gaseous envelope extending approximately up to what altitude above Earth’s surface?

Introduction / Context:
Atmospheric layering (troposphere, stratosphere, mesosphere, thermosphere, exosphere) is relevant to pollutant dispersion, satellite drag, and re-entry heating. A practical teaching reference asks for the approximate vertical extent of the atmosphere as a whole.

Given Data / Assumptions:

• We want an order-of-magnitude height for the atmospheric envelope.
• Significant mass resides below ~50 km, but trace gases and thermospheric particles extend much higher.
• We select from discrete options.

Concept / Approach:
Although most atmospheric mass lies below 50 km, the thermosphere and exosphere extend to hundreds or thousands of kilometers. A common instructional approximation places the upper bound around 1000 km to encompass the rarified outer layers still considered part of Earth’s atmosphere.

Step-by-Step Solution:
Eliminate very low bounds (10 km), which only cover the troposphere.200 km is too low to include large portions of the thermosphere/exosphere.1000 km is the best match among the given options for the overall atmospheric envelope.

Verification / Alternative check:
Spaceflight and satellite literature often describe atmospheric effects up to ~1000 km or more, even though density is extremely low there.

Why Other Options Are Wrong:
10 km / 50 km: represent inner layers only.200 km: excludes much of the thermosphere/exosphere envelope.2000 km: higher than many standard approximations used for environmental coursework.

Common Pitfalls:
Confusing “where most mass is” with “where the atmosphere ends.” The tail of extremely low-density gas extends far above the weather-bearing layers.

Final Answer:
1000 km