Why is the “source first” principle important when selecting controls for air contaminants?

• A. Addressing the source minimizes generation and spread of contaminants, often reducing the need for downstream controls
• B. Source controls are always expensive
• C. PPE alone suffices
• D. It is optional

Answer: (A)

Controlling a contaminant at its source stops it from being generated or released into the air in the first place, which greatly reduces worker exposure and simplifies or even eliminates the need for downstream controls. By enclosing the process, substituting with a less hazardous material, or capturing the contaminant right where it originates with local exhaust, you prevent spread through the space and reduce peak concentrations. When generation and dispersion are curtailed at the source, downstream measures like ventilation rates, filtration, or air cleaning can be smaller, less energy-intensive, or not required at all, making source control a very effective first step. PPE alone cannot prevent generation or stop a release and depends on proper use and fit, so it cannot serve as the primary protective strategy. It's not a matter of option; addressing the source is the preferred approach whenever feasible, with other controls serving as backups when source reduction isn't possible.