In air quality management, emission inventories are used for which of the following purposes?

• A. Tracking changes in emissions over time to identify trends.
• B. Forecasting the economy.
• C. Measuring rainfall.
• D. Planning transportation routes.

Answer: (B)

Emission inventories quantify how much of various pollutants are released from all sources in a region over a defined time. The main purpose is to track changes in those emissions over time, so trends can be identified, policy effectiveness can be assessed, and the most significant sources can be targeted for reductions. These inventories also feed air-quality models to predict concentrations and evaluate control strategies. They aren’t used to forecast the economy, measure rainfall, or directly plan transportation routes, though the resulting data can inform broader planning decisions.