Nuclear Analytical Techniques i n Particle Air Pollution Monitoring

1. Nuclear Analytical Techniques in Particle Air Pollution Monitoring Grizel Pérez, Ibrahin Piñera Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear CEADEN Septiembre 14, 2011

2. G. Pérez Sept. 14 2011 Content • Introduction • Nuclear Analytical Techniques in PM monitoring • Physical Principles • Main characteristics • PM sampling • Application example • Conclusions

3. G. Pérez Sept. 14 2011 Introduction Air pollution has become a matter of global concern, particularly in some of the world's largest cities. It is made up of many different components that affect the environment - and directly or indirectly the health of people. The main components include sulphur dioxide, particulate matter, carbon monoxide, reactive hydrocarbon compounds, nitrogen oxides, ozone, and lead. Nuclear techniques have important applications in the study of nearly all of them. However, it is in the study of airborne particulate matter (APM) that nuclear analytical techniques find many of their most important applications.

4. G. Pérez Sept. 14 2011 NATs in PM monitoring PM nuclear analysismethods Airborne particulate matter retained on the filter may be examined or analyzed chemically by a variety of methods. In this presentation, only nuclear analytical techniques (NATs) are considered because of their advantages in analyzing many elements in air particulate matter non-destructively and simultaneously. The key three NATs for analysis of particulate matter in air are:

5. G. Pérez Sept. 14 2011 NATs in PM monitoring PM nuclear analysismethods Airborne particulate matter retained on the filter may be examined or analyzed chemically by a variety of methods. In this presentation, only nuclear analytical techniques (NATs) are considered because of their advantages in analyzing many elements in air particulate matter non-destructively and simultaneously. The key three NATs for analysis of particulate matter in air are:

6. G. Pérez Sept. 14 2011 Physical Principles of NATs NeutronActivationAnalysis (NAA) In typical NAA, a sample is exposed to a high flux of thermal neutrons in a nuclear reactor or accelerator. NAA is based on the interaction of a neutron (n) with a target nucleus (AZ) where the neutron is captured and gamma rays are emitted.

7. G. Pérez Sept. 14 2011 Physical Principles of NATs NeutronActivationAnalysis (NAA) In typical NAA, a sample is exposed to a high flux of thermal neutrons in a nuclear reactor or accelerator. NAA is based on the interaction of a neutron (n) with a target nucleus (AZ) where the neutron is captured and gamma rays are emitted. • Thespectrum of gamma rays energy determines the specific isotopes present in the sample. • The intensity of the gamma rays is proportional to the amounts of elements present. • Typically 5 counting regimes are required to detect these elements (300 s, 1 hr, 10 hr, 4 days and 15 days). • It is highly sensitive (ppb), it does not quantify elements such as Si, Ni, Co, and Pb. Typical elemental detection limits range from 0.01 to 10 ng m-3. • NAA is a simultaneous, multi-element method that can be used to measure 40-45 elements.

8. G. Pérez Sept. 14 2011 Physical Principles of NATs X-RayFluorescence(XRF) XRF is based on the measurements of the energies and intensities of the characteristic X-rays excited in different materials by using an external source of electromagnetic radiation (usually X-ray tubes or radioisotope sources).

9. G. Pérez Sept. 14 2011 Physical Principles of NATs X-RayFluorescence(XRF) XRF is based on the measurements of the energies and intensities of the characteristic X-rays excited in different materials by using an external source of electromagnetic radiation (usually X-ray tubes or radioisotope sources). • XRF can be used for all elements with Z from 11 (Na) to 92 (U). • Typical elemental detection limits for this method range between 2 and 2000 ngm-3. • XRF depends on the availability of excellent PM standards. • Shorter analysis time than NAA. • XRF can be used for simultaneous determination of 20-25 elements.

10. G. Pérez Sept. 14 2011 Physical Principles of NATs Ion BeamAnalysis(IBA) IBA is based on the interaction, at both the atomic and the nuclear level, between accelerated charged particles and the bombarded material.

11. G. Pérez Sept. 14 2011 Physical Principles of NATs Ion BeamAnalysis(IBA) IBA is based on the interaction, at both the atomic and the nuclear level, between accelerated charged particles and the bombarded material. • These techniques are used simultaneously as key analytical tools to assess PM pollution on a regular basis. • The choice of analytical method depends on the inorganic compounds of interest and the detection limits desired. • Using the four different analysis techniques (PIXE, PIGE, PESA, RBS), IBA can measure more than 40 elements (H – U).

12. G. Pérez Sept. 14 2011 Physical Principles of NATs Particle Induced X-ray Emission Analysis (PIXE) • PIXE is a powerful and relatively simple analytical technique that can be used to identify and quantify trace elements typically ranging from Na to U. • Sample irradiation is usually performed by means of 2-3 MeV protons produced by an accelerator. • Xraydetection is usually done by energy dispersive semiconductor detectors such as Si(Li) or HP Ge detectors. • This multi-elemental analysis technique can measure more than 30 elements in short times due to higher cross-sections as compared to XRF. • With the addition of PIGE and PESA, allows for the detection of light elements that is useful for source identification and apportionment and estimation of organic carbon. • Typical detection limits range from 1 to 50 ng m-3.

13. G. Pérez Sept. 14 2011 Physical Principles of NATs Particle Induced X-ray Emission Analysis (PIXE) The remaining three methods are used simultaneously to achieve additional information on elements that can not or hardly be measured with PIXE.

14. G. Pérez Sept. 14 2011 Main characteristics of NATs

15. G. Pérez Sept. 14 2011 NATs in PM monitoring APM: usually collected by air filtering • Typical load: 50 – 700 mg/cm2 • Composition: Soil, soot, salts, industrial released • Particle size: ~ 0.1 to 50 mm • Filter media: • Teflon • Cellulose • Membrane (non-coated, coated) • Dichotomous sampler (used under IAEA coordinated research projects and TC projects) (i) two fractions: 10 to 2.5 m and < 2.5 m (ii) 8 m and 0.4 m pore 47 mm Nuclepore Filters; Flow rate 16 lpm (iii) sampling time: 24 h for particle mass concentrations smaller than50 g/m3; Two days – 10-15 g/m3 • NAA is compatible with sampling by high-volume (TSP; PM10) and dichotomous samplers. • Quartz filters used in high-volume samplers cause high background XRF and PIXE analysis, filters used in the dichotomous samplers are preferable. • PM2.5 collection by dichotomous samplers is typicallyinvolved by PIXE analysis.

16. G. Pérez Sept. 14 2011 Application example IAEA ARCAL Project RLA/7/ 011, ARCAL LXXX : ASSESSMENT OF ATMOSPHERIC POLLUTANTS BY PARTICLES (2005-2008) Argentina, Chile, Costa Rica, Cuba, DominicanRepublic, Mexico, Uruguay, Venezuela. • General Objectives: • To impel the research in the field of monitoring air pollution with emphasis on particles. • Sample collection of airborne particulate matter (including course and fine) simultaneously. • The use of nuclear technology to characterize airborne particulate matter. CEADEN

17. Infanta Ave. & Manglar, Centro Habana, Havana City, Cuba. Urban site with high traffic and densely populated 23.12 N 82.4 W Environmental Monitoring Station

18. G. Pérez Sept. 14 2011 Samplingsite at INHEM

19. G. Pérez Sept. 14 2011 Possiblepollutionsites samplingsite

20. G. Pérez Sept. 14 2011 Samples and data collection Air Sampler type GENT with stacked filter unit for collecting the aerosol in two size fraction (PM2,5 and PM10) simultaneously. Samplingperiod: November 14, 2006 to April, 2007. Total 5 months. Sampling frequency: Every second day with 24 h duration.

21. G. Pérez Sept. 14 2011 Samplespreparation Microbalance: Cahn C-35 Resolution: 0.1 µg

22. G. Pérez Sept. 14 2011 Gravimetric analysis Descriptive statistics of the data (µg/m3).

23. G. Pérez Sept. 14 2011 PIXE analysis Tandetron Accelerator, PIXE Analysis Lab. ININ, Mexico. I = 15 nA Q = 6 mC OrtecSi(Li) detector active area = 80 mm2 resolution = 200 eV at 5.9 keV (Mn-Kα, 55Fe) Protons 2.5 MeV sample x

24. G. Pérez Sept. 14 2011 PIXE analysis 14 elements were consistently detected in the samples

25. G. Pérez Sept. 14 2011 Elemental analysis Softwares for spectra processing AXIL & WINAXIL_4.5.3

26. G. Pérez Sept. 14 2011 Elemental analysis

27. G. Pérez Sept. 14 2011 Elemental analysis

28. G. Pérez Sept. 14 2011 Statistical analysis • Descriptive statistic. • Correlation Matrix. • Principal Component Matrix. • Rotated Principal Component Matrix by the maximum variability criteria. • Component profiles and identification of the main sources (Factors). • Scores of the found Factors. • Contributions from sources to element concentrations.

29. G. Pérez Sept. 14 2011 Rotated Principal Component Matrix fine mode

30. G. Pérez Sept. 14 2011 Source identification & apportionment fine mode

31. G. Pérez Sept. 14 2011 Sources apportionment fine mode

32. G. Pérez Sept. 14 2011 Rotated Principal Component Matrix coarse mode

33. G. Pérez Sept. 14 2011 Source identification & apportionment coarse mode

34. G. Pérez Sept. 14 2011 Sources apportionment coarse mode

35. G. Pérez Sept. 14 2011 Conclusions • Nuclear Analytical Techniques can be used for determination of the elemental composition of coarse and fine particulate matter: neutron activation analysis, X-ray fluorescence, and ion beam analysis (PIXE, PIGE, PESA, RBS). • Since the various types of sources of particulate air pollutants are characterized by the elemental composition of the particles, knowledge of the elements in particles allows the identification of the origin of the particles and, thereby, leads to a quantitative apportionment of the existing types of sources. • In consequence, most important source types can be identified and decisions can be made on which source types it is most appropriate to reduce emissions. • This would constitute a valuable step forward in air quality management, particularly in cases where emissions inventories are not established. • In our case, the results provided by PIXE in combination with appropriated statistical analysis allow us to identify the source profiles and contribution, providing important information about atmospheric pollution in selected site, necessary to develop strategies and to establish appropriate policies on pollution control.

36. G. Pérez Sept. 14 2011 Conclusions • Nuclear Analytical Techniques can be used for determination of the elemental composition of coarse and fine particulate matter: neutron activation analysis, X-ray fluorescence, and ion beam analysis (PIXE, PIGE, PESA, RBS). • Since the various types of sources of particulate air pollutants are characterized by the elemental composition of the particles, knowledge of the elements in particles allows the identification of the origin of the particles and, thereby, leads to a quantitative apportionment of the existing types of sources. • In consequence, most important source types can be identified and decisions can be made on which source types it is most appropriate to reduce emissions. • This would constitute a valuable step forward in air quality management, particularly in cases where emissions inventories are not established. • In our case, the results provided by PIXE in combination with appropriated statistical analysis allow us to identify the source profiles and contribution, providing important information about atmospheric pollution in selected site, necessary to develop strategies and to establish appropriate policies on pollution control.

37. G. Pérez Sept. 14 2011 Conclusions • Nuclear Analytical Techniques can be used for determination of the elemental composition of coarse and fine particulate matter: neutron activation analysis, X-ray fluorescence, and ion beam analysis (PIXE, PIGE, PESA, RBS). • Since the various types of sources of particulate air pollutants are characterized by the elemental composition of the particles, knowledge of the elements in particles allows the identification of the origin of the particles and, thereby, leads to a quantitative apportionment of the existing types of sources. • In consequence, most important source types can be identified and decisions can be made on which source types it is most appropriate to reduce emissions. • This would constitute a valuable step forward in air quality management, particularly in cases where emissions inventories are not established. • In our case, the results provided by PIXE in combination with appropriated statistical analysis allow us to identify the source profiles and contribution, providing important information about atmospheric pollution in selected site, necessary to develop strategies and to establish appropriate policies on pollution control.

38. G. Pérez Sept. 14 2011 Conclusions • Nuclear Analytical Techniques can be used for determination of the elemental composition of coarse and fine particulate matter: neutron activation analysis, X-ray fluorescence, and ion beam analysis (PIXE, PIGE, PESA, RBS). • Since the various types of sources of particulate air pollutants are characterized by the elemental composition of the particles, knowledge of the elements in particles allows the identification of the origin of the particles and, thereby, leads to a quantitative apportionment of the existing types of sources. • In consequence, most important source types can be identified and decisions can be made on which source types it is most appropriate to reduce emissions. • This would constitute a valuable step forward in air quality management, particularly in cases where emissions inventories are not established. • In our case, the results provided by PIXE in combination with appropriated statistical analysis allow us to identify the source profiles and contribution, providing important information about atmospheric pollution in selected site, necessary to develop strategies and to establish appropriate policies on pollution control.

39. G. Pérez Sept. 14 2011 Conclusions • Nuclear Analytical Techniques can be used for determination of the elemental composition of coarse and fine particulate matter: neutron activation analysis, X-ray fluorescence, and ion beam analysis (PIXE, PIGE, PESA, RBS). • Since the various types of sources of particulate air pollutants are characterized by the elemental composition of the particles, knowledge of the elements in particles allows the identification of the origin of the particles and, thereby, leads to a quantitative apportionment of the existing types of sources. • In consequence, most important source types can be identified and decisions can be made on which source types it is most appropriate to reduce emissions. • This would constitute a valuable step forward in air quality management, particularly in cases where emissions inventories are not established. • In our case, the results provided by PIXE in combination with appropriated statistical analysis allow us to identify the source profiles and contribution, providing important information about atmospheric pollution in selected site, necessary to develop strategies and to establish appropriate policies on pollution control.

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