Urban air pollution monitoring: laser-based procedure for the detection of carbon monoxide gas

Abstract

Urban air quality is of considerable importance in many cities throughout Europe and the USA. In particular, current EU legislation has driven an expansion of monitoring of more pollutants at more sites. At present in the UK, real time readings are now available for benzene, buta-1,3-diene and other volatile organic compounds, airborne fine dust (PM₁₀), CO, O₃, SO₂ and NO_x. Carbon monoxide is produced to varying degrees in all combustion processes but more than 90% is caused by emissions from petrol vehicle exhausts. The World Health Organisation guidelines for exposure to the gas is <10 ppm for 8 h and 85 ppm for periods not exceeding 15 min. All of the pollutants mentioned above are monitored by different detection techniques and it has been the authors’ philosophy to develop instrumentation which can monitor all the different pollutants using a single detector. To this end, a multiphoton laser based procedure, using simple ionization chambers, has been developed to detect the different pollutants with different wavelengths. For CO, a 2 + 1 resonance enhanced multiphoton ionization (REMPI) scheme at 230 nm can be used with detection limits of about 1 ppm.

References

1. R. M. Harrison, Chem. Br., 1994, 987.
2. Quality of Urban Air Review Group, Urban Air Quality in the United Kingdom, Department of the Environment, London, 1993.
3. Quality of Urban Air Review Group, Diesel Vehicle Emissions and Urban Air Quality, Department of the Environment, London, 1993.
4. Advisory Group on the Medical Aspects of Air Pollution Episodes, Oxides of Nitrogen, HM Stationery Office, London, 1993.
5. Department of the Environment, Improving Air Quality, Discussion Paper on Air Quality Standards and Management, HM Stationery Office, London, 1994.
6. Department of the Environment, Air Quality:Meeting the Challenge, HM Stationery Office, London, 1995.
7. Expert Panel on Air Quality Standards Ozone, HM Stationery Office, London, 1994.
8. Critical Levels of Air Pollutants for Europe, ed. Ashmore, M. R., and Wilson, R. B., Department of the Environment, London, 1992.
9. P. M. Meyer and M. W. Sigrist, Rev. Sci. Instrum., 1990, 61, 1779.
10. R. T. Ku, E. D. Hinkley and J. O. Sample, Appl. Opt., 1975, 14, 854.
11. C. W. Sachse, G. F. Hill, L. O. Wade and M. G. Perry, J. Geophys. Res., 1987, 92, 2071.
12. A. Fried, B. Herry, D. D. Parrish, J. R. Carpenter and M. P. Buhr, Atmos. Environ., Part A, 1991, 25, 2277.
13. M. A. A. El Karim, M. Khogali and H. Zeqlam, Sci. Total Environ., 106, 111.
14. S. Guizard, D. Chapoulard, M. Horani and D. Gauyacq, Appl. Phys. B, 1989, 48, 471.
15. M. O. Rodgers, K. Asai and D. D. Davis, Appl. Opt., 1980, 19, 3597.
16. J. M. Hoell, Jr., G. L. Gregory, D. S. McDougal, A. L. Torres, D. D. Davis, J. Bradshaw, M. O. Rodgers, B. A. Ridley and M. A. W. Carroll, J. Geophys. Res., 1987, 92, 1995.
17. M. Hippler, A. Q. J. Yates and J. Pfab, Inst. Phys. Conf. Ser., 1991, 113, 303.
18. J. B. Simeonsson, G. W. Lemire and R. C. Sausa, Anal. Chem., 1994, 66, 2272.
19. A. Marshall, K. W. D. Ledingham and R. P. Singhal, Analyst, 1995, 120, 2069.
20. A. Marshall, A. Clark, R. M. Deas, C. Kosmidis, K. W. D. Ledingham, W. Peng and R. P. Singhal, Analyst, 1994, 119, 1719.
21. W. X. Peng, K. W. D. Ledingham, A. Marshall and R. P. Singhal, Analyst, 1995, 120, 2537.
22. A. Clark, C. Kosmidis, R. M. Deas, K. W. D. Ledingham, A. Marshall, J. Sander and R. P. Singhal, J. Phys. D: Appl. Phys., 1993, 26, 2107.
23. C. Weickardt, U. Boesl and E. W. Schlag, Anal Chem., 1994, 66, 1062.
24. J. Pfab, in Spectroscopy in Environmental Sciences, ed. Clark, R. J. H., and Hester, R. E., Wiley, Chichester, 1995, pp. 149–222.
25. K. W. D. Ledingham and M. Campbell, in Sensor Systems for Environmental Monitoring, ed. Campbell, M., Blackie, Glasgow, 1997, vol. 1, pp. 65–99.
26. J. P. Looney, J. E. Harrington, K. C. Smyth, T. R. O'Brian and T. B. Lucatorto, J. Vac. Sci. Technol., A, 1993, 11, 3111.
27. S. T. Pratt, E. D. Poliakoff, P. M. Dehmer and J. L. Dehmer, J. Chem. Phys., 1983, 77, 65.
28. G. W. Loge, J. J. Tiee and F. B. Wampler, J. Chem. Phys., 1983, 79, 196.
29. P. J. H. Tjossem and K. C. Smyth, J. Chem. Phys., 1989, 91, 2041.
30. T. A. Spiglanian, R. A. Perry and D. W. Chandler, J. Chem. Phys., 1987, 87, 1568.
31. B. Jiang, G. Sha, C. Zhang, J. He, S. Xu and C. Zhang, J. Chem. Phys., 1992, 97, 4697.
32. G. W. Loge, J. J. Tiee and F. B. Wampler, J. Chem. Phys., 1983, 79, 196.
33. S. M. Koeckhoven, W. J. Buma and C. A. de Lange, J. Chem. Phys., 1993, 99, 5061.
34. M. A. Hines, H. A. Micelson and R. N. Zare, J. Chem. Phys., 1990, 93, 8557.
35. H. Rottke and H. Zacharias, Opt. Commun., 1985, 55, 87.
36. G. Herzberg, Molecular Spectra and Molecular Structure. 1 Spectra of Diatomic Molecules, Van Nostrand Reinhold, New York, 1950.
37. J. Haumann, J. M. Seitzman and R. K. Hanson, Opt. Lett., 1986, 11, 776.
38. J. M. Seitzman, J. Haumann and R. K. Hanson, Appl. Opt., 1987, 26, 2892.
39. W. X. Peng, K. W. D. Ledingham and R. P. Singhal, Resonance Ionization Spectroscopy 1996, ed. Winograd, N., and Parks, J. E., AIP Conference Proceedings No. 388, AIP Press, Woodbury, NY, 1997, p. 219.
40. L. F. DiMauro and T. A. Miller, Chem. Phys. Lett., 1987, 138, 175.
41. M. Drabbels, J. Heinze, J. J. Meulen and W. L. Meets, J. Chem. Phys., 1993, 99, 5701.
42. A. Clark, C. Kosmidis, R. M. Deas, K. W. D. Ledingham, A. Marshall, J. Sander and R. P. Singhal, J. Phys. D: Appl. Phys., 1993, 26, 2107.
43. C. Kosmidis, K. W. D. Ledingham, A. Clark, A. Marshall, R. Jennings, J. Sander and R. P. Singhal, Int. J. Mass Spectrom., Ion Processes, 1994, 135, 229.