Real-time air monitoring with multiple sensing modes

1. A gas detector comprising:

a first gas sensor having a fluid inlet for receiving a gas sample and a fluid outlet for exhausting the gas sample, the first sensor having a first gas specificity and a first response time;

a second gas sensor having a fluid inlet for receiving the gas sample and a fluid outlet for exhausting the gas sample, the second sensor having a second gas specificity and a second response time, wherein the first gas specificity is different than the second gas specificity, the first response time is different than the second response time, or both the first gas specificity and the first response time are different than the second gas specificity and the second response time;

a readout and analysis circuit coupled to the first and second gas sensors to read and analyze data from the first and second gas sensors; and

a control circuit coupled to the readout and analysis circuit and to the first and second gas sensors, wherein the control circuit can execute logic that operates the first gas sensor, the second gas sensor, or both the first and second gas sensors.

2. The gas detector of claim 1 wherein the first gas sensor is a fast-response low-specificity sensor and the second gas sensor is a fast-response partial-specificity sensor.

3. The gas detector of claim 1 wherein the first gas sensor is a fast-response partial-specificity sensor and the second gas sensor is a slow-response high-specificity sensor.

4. The gas detector of claim 1 wherein the control circuit operates the first gas sensor independently of the second gas sensor.

5. The gas detector of claim 1 wherein the control circuit operates the second gas sensor if the result obtained from the first gas sensor meets specified criteria for activating the second gas sensor.

6. The gas detector of claim 1 , further comprising a third gas sensor having a fluid inlet for receiving the gas sample and a fluid outlet for exhausting the gas sample, the third sensor having a third gas specificity and a third response time and being coupled to the control circuit.

7. The gas detector of claim 6 wherein:

the first gas sensor is a fast-response low-specificity sensor,

the second gas sensor is a fast-response partial-specificity sensor, and

the third gas sensor is a slow-response high-specificity sensor.

8. The gas detector of claim 6 wherein the control circuit operates the first, second, and third gas sensors independently.

9. The gas detector of claim 8 wherein the detector is coupled to a gas sampling manifold with single or multiple inlets for sampling from multiple locations.

10. The gas detector of claim 6 wherein the control circuit operates the second gas sensor if the result obtained from the first gas sensor meets specified criteria for activating the second gas sensor.

11. The gas detector of claim 10 wherein the control circuit returns to operation of the first gas sensor when the second gas sensor has completed its sensing.

12. The gas detector of claim 10 wherein the control circuit operates the third gas sensor if the second gas sensor was operated and if the result obtained from the second gas sensor meets specified criteria for activating the third gas sensor.

13. The gas detector of claim 12 wherein the control circuit returns to operation of the first gas sensor or the second gas sensor when the third gas sensor has completed its sensing.

14. The gas detector of claim 6 wherein the control circuit can select the second gas sensor or the third gas sensor, depending on whether the result obtained from the first gas sensor meets specified criteria for operating the second gas sensor or meets specified criteria for activating the third gas sensor.

15. The gas detector of claim 14 wherein the control circuit returns to operation of the first gas sensor when the second gas sensor has completed its sensing or returns to operation of the second gas sensor when the third gas sensor has completed its sensing.