Which statement correctly contrasts Direct Reading Instruments with Sample Collection Devices?

Which statement correctly contrasts Direct Reading Instruments with Sample Collection Devices?

• A. Direct Reading Instruments provide results only after lab analysis
• B. Sample Collection Devices provide immediate results
• C. Direct Reading Instruments provide immediate results
• D. Both require lab analysis

Answer: (C)

Direct Reading Instruments are designed to give measurements in real time right in the field, so you see a reading immediately as the sensor responds. This lets you assess conditions or exposure and take action right away. In contrast, devices that collect a sample (like filters, sorbent tubes, or canisters) are used to gather material over a period or at a specific moment and then send that sample to a laboratory for analysis. The lab work determines the concentration, so you don’t get the result until results are back, which means there’s a delay. Because of this, the correct statement is that Direct Reading Instruments provide immediate results. The other options misstate where immediacy comes from and imply that lab analysis is needed for direct-reading devices, which isn’t the case.

Direct Reading Instruments are designed to give measurements in real time right in the field, so you see a reading immediately as the sensor responds. This lets you assess conditions or exposure and take action right away. In contrast, devices that collect a sample (like filters, sorbent tubes, or canisters) are used to gather material over a period or at a specific moment and then send that sample to a laboratory for analysis. The lab work determines the concentration, so you don’t get the result until results are back, which means there’s a delay. Because of this, the correct statement is that Direct Reading Instruments provide immediate results. The other options misstate where immediacy comes from and imply that lab analysis is needed for direct-reading devices, which isn’t the case.