Continuous diffusion denuding with moving denuding surface

1. A denuding apparatus comprising:

a duct configured to receive a denuding gas flow;

a solid denuding surface positioned at least partially within the duct and configured to concentrate a gas-phase species from the denuding gas flow on the denuding surface;

a drive system connected to the solid denuding surface, the drive system being configured to move the solid denuding surface relative to the duct while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on the denuding surface; and

a sensor configured to sense quantities of the gas-phase species concentrated on the denuding surface while the drive system moves the solid denuding surface relative to the duct and while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on the denuding surface.

2. The apparatus of claim 1 , wherein the denuding surface comprises a continuous surface and the apparatus further comprises a treatment zone through which the solid denuding surface is configured to pass to refresh one or more denuding properties of the solid denuding surface.

3. The apparatus of claim 1 , wherein the sensor is further configured to quantify quantities of the gas-phase species.

4. The apparatus of claim 3 , further comprising a data processing and reporting system that is configured to receive data from the sensor, process the data, and reports results of the processing.

5. The apparatus of claim 1 , wherein the denuding surface is a surface of a flexible sheet.

6. The apparatus of claim 1 , wherein the denuding surface is oriented vertically while sampling the gas phase species.

7. The apparatus of claim 1 , wherein the apparatus further comprises a slip stream flow duct leading from a main gas flow, the slip stream flow duct carrying a slip stream flow from which the denuding gas flow is received.

8. The apparatus of claim 1 , wherein the denuding surface is a surface of a reactive coating on a substrate.

9. A denuding apparatus comprising:

a duct configured to receive a denuding gas flow;

a solid denuding surface positioned at least partially within the duct and configured to concentrate a gas-phase species from the denuding gas flow on the denuding surface;

a drive system connected to the solid denuding surface, the drive system being configured to move the solid denuding surface relative to the duct while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on the denuding surface; and

a sensor configured to sense quantities of the gas-phase species concentrated on a first portion of the denuding surface located outside the duct while the drive system moves the solid denuding surface relative to the duct and while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on a second portion of the denuding surface that is positioned within the duct.

10. The apparatus of claim 9 , wherein the denuding surface comprises a continuous surface and the apparatus further comprises a treatment zone through which the solid denuding surface is configured to pass to refresh one or more denuding properties of the solid denuding surface.

11. The apparatus of claim 9 , wherein the sensor is further configured to quantify quantities of the gas-phase species.

12. The apparatus of claim 11 , further comprising a data processing and reporting system that is configured to receive data from the sensor, process the data, and report results of the processing.

13. The apparatus of claim 9 , wherein the denuding surface is a surface of a flexible sheet.

14. The apparatus of claim 9 , wherein the denuding surface is oriented vertically while sampling the gas phase species.

15. The apparatus of claim 9 , wherein the apparatus further comprises a slip stream flow duct leading from a main gas flow, the slip stream flow duct carrying a slip stream flow from which the denuding gas flow is received.

16. The apparatus of claim 9 , wherein the denuding surface is a surface of a reactive coating on a substrate.

17. A denuding apparatus comprising:

a duct configured to receive a denuding gas flow;

a solid denuding surface positioned at least partially within the duct and configured to concentrate a gas-phase species from the denuding gas flow on the denuding surface, the solid denuding surface being a surface of a reactive coating on a flexible sheet;

a drive system connected to the solid denuding surface, the drive system being configured to move the solid denuding surface relative to the duct while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on the denuding surface; and

a sensor configured to sense quantities of the gas-phase species concentrated on a first portion of the denuding surface located outside the duct while the drive system moves the solid denuding surface relative to the duct and while the solid denuding surface is concentrating the gas-phase species from the denuding gas flow on a second portion of the denuding surface that is positioned within the duct.

18. The apparatus of claim 17 , wherein the sheet is a tape.

19. The apparatus of claim 17 , wherein the sensor is further configured to quantify quantities of the gas-phase species.

20. The apparatus of claim 19 , further comprising a data processing and reporting system that is configured to receive data from the sensor, process the data, and report results of the processing.