Pulmonary function assessment through non-invasive techniques-effects of exposure to air pollution

(1)

PULMONARY FUNCTION ASSESSMENT THROUGH NON-INVASIVE TECHNIQUES - EFFECTS OF EXPOSURE TO AIR POLLUTION

by

RACHNA AGARWAL Centre for Biomedical Engineering

Submitted

in fulfillment of the requirements of the degree of Doctor of Philosophy

to the

Indian Institute of Technology — Delhi

January 2005

(2)

CERTIFICATE

This is to certify that the thesis entitled 'Pulmonary Function Assessment through Non-Invasive Techniques — Effects of Exposure to Air Pollution', being submitted by Ms. Rachna Agarwal for the award of the degree of DOCTOR OF PHILOSOPHY, is a record of the original bonafide research work carried out by her. She has worked under our guidance and supervision and has fulfilled the requirements for the submission of the thesis. The results presented in this thesis have not been submitted in part or full to any other University or Institution for award of any degree/diploma.

(Dr.Sneh Anand)

Professor,

Centre for Biomedical Engineering, Indian Institute of Technology, Delhi Hauz Khas, New-Delhi-110016, India

(Dr.Girija ayaraman)

Professor, Centre for Atmospheric Sciences, Indian Institute of Technology, Delhi Hauz Khas, New-Delhi-110016, India

(3)

Dedicated To

My Dear Parents

(4)

ACKNOWLEDGEMENT

I am thankful to the institute — IIT, Delhi for giving me an opportunity to study under its vast umbrella of knowledge.

I am indebted to my supervisors, Prof Sneh Anand and Prof Girija Jayaraman, for encouraging me from time to time, for their constant support, and above all for their valuable advice. Their progressive outlook towards science and hard working attitude has always inspired me. I would like to thank them for all their efforts that have made me a better person with regard to the academic and professional life. I have imbibed in me a sense of punctuality and professional ethics from Prof Jayaraman for which I will always be grateful. I extend special thanks to Prof Anand who has always helped me in times of difficulty despite her busy schedule and ill health.

I am thankful to Prof Harpal Singh, Head, Centre for Bio-medical Engineering (CBME) for his encouragement and for providing the necessary facilities. I also extend my thanks to the entire faculty and staff of CBME. Special thanks to Mr. KL Batra for his help during the research.

I sincerely thank Prof S.KDube, Director, IIT-Kharagpur and former Head, Centre for Atmospheric Sciences (CAS), IIT Delhi for being a constant source of encouragement and support all along my research work I extend thanks to all the support staff members of CAS.

I gratefully acknowledge the financial support of the Council for Scientc and Industrial Research (CSIR). I extend thanks to Dr. A.P. Mitra, former D.G, CSIR, and Mr. Prabaht Gupta, at N.P.L, CSIR for giving me an opportunity to work with them.

I would like to thank Dr. J.0 .Suri and Dr. M.K. Sen of Safdarjung Hospital for their valuable help. I would also like to thank Dr. Jaiswal and Dr. M Sircar at

(5)

Lala Ram Swarup (LRS) Chest Institute, for teaching the details of Spirometry. I would like to thank the laboratory technicians Mr. Manoj, Mr. Ashok and Mr.

Dharmendra at the two hospitals.

I sincerely thank Dr. Makhijani, Central Pollution Control Board (CPCB) and Mr. Dharmendra Gupta at ITO monitoring station for all their help and support from time to time. Air pollution data provided by the CPCB is an indispensable part of the study.

I also thank Dr. M.C. Kapilashrami former Director National Institute of Health and Family Welfare (NIHF11), and Dr. J.K Das, former Head MCHA for their encouragement and support during my research work I would like to thank Dr.

P. Marimuthu, Lecturer, Dept. of Statistics, NIHFW for his valuable suggestions.

I also extend my thanks to Mr. A.K Biswas, Head Kolkata zonal laboratory, NEERI, for all his help, support and thoughtfulness.

I would also like to thank my sister Dr.Nupur Agarwal and all my colleagues and friends at HT- Rajeev, Prakriti, Shveta, Mandal and at NIHFW — Rajiv, Jai, Gaurav, Pradeep and Ramesh who have been very helpful during my research work

Lastly, and above all I thank God for his blessings as well as my mother Dr.Rekha Agarwal and father Dr. A.K. Agarwal for their good wishes and valuable counseling from time to time. Without their support I would not have been able to accomplish my objectives.

(Rachnd Agarwal)

(6)

Abstract

Incidence of asthma and other respiratory problems are globally on the rise mainly due to deteriorating air quality. An attempt has been made to investigate health effects of ambient air pollution. Assessment of Delhi's ambient air pollution over the past 15 years (1989-2003) indicated that ITO intersection was the most polluted area on account of vehicular traffic. Contribution of pollutants and meteorological factors to various respiratory diseases was evaluated and two pollutants — SPM and RSPM were found to correlate well with respiratory obstruction. An assessment of the pulmonary function status amongst local residents was made onsite using a portable spirometer. Comparison was made for different groups- smokers, non-smokers, young and middle aged subjects. This study was further extended to a group of subjects residing in a suburban village free from vehicular pollution but exposed to bio-fuel emissions. Statistical analysis revealed that while in urban area it was the younger population that was more at risk; in suburban area the middle aged smokers were at a greater risk. Also, non-smoking suburban females were seen to have reduced lung capacities with greater years of exposure to bio-fuels emissions. Amongst the various PFT parameters, FEF25-75 impairment in both young and middle aged population indicates that small airways were the worst affected. A comparison was also made for the status of lung function amongst urban and sub-urban population and the latter was found to have higher risk of pulmonary function impairment. Electrical Impedance Plethysmography (EIP) technique that does not require subject intervention was explored for its potential use in detecting pulmonary health status. EIP parameters were compared with spirometry and it revealed that both respiratory amplitude and respiratory band power can provide useful information on pulmonary health status.

EIP is a good substitute to conventional spirometry and its parameters correspond to the respiratory airflows rather than lung volumes.

(7)

Schematic Diagram of Organization of the Thesis

Chapter 1 General Introduction

(Pulmonary System, Air Pollution & Health Effects) Literature Review

Chapter 2

Pollution analysis (15 yrs.) &

Respiratory Morbidity study

Correlation and Regression analysis between pollutants,

meteorological variables &

respiratory ailments

1

Identifying worst polluted area of Delhi for further

study

Chapter 3

Study Design, Methodology, Pulmonary Function Tests

Assessing the effect of smoking with age & exposure to vehicular emissions amongst the subjects of the identified study area

Chapter 4

Comparing Lung function status:

- Suburban smokers, non-smokers - Bio-fuels exposed subjects

Comparing Lung function status between Urban &

Suburban subjects

Chapter 5 Electrical Impedance Plethysmography (EIP) technique - detecting pulmonary function status

in normal & impaired subjects

• Chapter 6 Thesis Summary (Results & Discussions,

future scope of work)

(8)

1.2.1 Particulate Matter and Health Effects 5 1.2.2 Sulfur dioxide/acid aerosols and Health Effects 10 1.2.3 Nitrogen oxides and Health Effects 11 1.2.4 Health Effects of Vehicular and bio-fuels pollution 14 1.2.5 National Review of Adverse Effects on Pulmonary Health 15 1.2.6 International Review of Adverse Effects on Pulmonary Health 16

1.3 Pulmonary System 20

1.3.1 Pulmonary Functioning 20

1.3.2 Pulmonary Disorders 22

1.3.3 Measurement Techniques 25

1.3.3.1 Spirometry 26

1.3.3.2 Electrical Impedance Plethysmography 28

1.4 Summary 31

2. CHAPTER II:

RESPIRATORY MORBIDITY AND POLLUTION STATUS 33 - 71

2.1 Introduction 33

2.2 Overview of the study area - Delhi 35

2.3 Respiratory morbidity study 36

ii

(9)

2.3.1 Analysis of pollution and respiratory admissions 36 2.3.2 Comparing pollutants, meteorological variables and

Respiratory admissions 47

2.3.3 Multivariate Regression Analysis 53

2.4 Air Pollution Status 55

2.4.1 Fifteen years (1989-2003) analysis 55 2.4.2 Monthly analysis of pollution at seven sites in Delhi 61 2.4.3 Air quality status pre and post CNG implementation 64

2.5 Results and Discussion 66

2.6 Summary 70

3. CHAPTER III: PULMONARY FUNCTION ASSESSMENT IN

URBAN EXPOSED POPULATION 72 - 96

3.1 Introduction 72

3.2 Methodology 73

3.2.1 Study Site 73

3.2.2 Selection of Subjects 76

3.2.3 Sample Size Estimation 78

3.2.4 Measurement of Pulmonary Function 79 3.2.5 Statistical Analysis - Comparing urban population with respect

to age, smoking habit and exposure to vehicular emissions 86

3.3 Results and Discussions 92

3.4 Summary 96

4. CHAPTER W: PULMONARY FUNCTION ASSESSMENT IN

VEHICULAR VERSUS BIO-FUELS EXPOSED GROUPS 97 —125

4.1 Introduction 97

4.2 Methodology 99

4.2.1 Pulmonary Function Test Results 101 4.2.2 Statistical Analysis - Comparing sub-urban population with regard to

age, smoking habit and exposure to bio-fuel emissions 103 iii

(10)

4.3 Comparing urban and sub-urban population 110

4.5 Summary 125

5. CHAPTER V:

ELECTRICAL IMPEDANCE PLETHYSMOGRAPHY TECHNIQUE IN ESTIMATING PULMONARY FUNCTION STATUS 126 - 147

5.1 Introduction 126

5.2 EIP Technique 128

5.2.1 Review 128

5.2.2 Overview of the Technique 131

5.3 Methodology 132

5.3.1 Subjects selection .. 132

5.3.2 EIP Data Acquisition 132

5.3.3 EIP Data Processing 134

5.3.4 EIP Data Analysis 134

5.3.5 PFT Data Collection 135

5.3.6 Statistical Analysis 140

5.3.6.1 Significance test 140

5.3.6.2 Correlation and Regression analysis 142

5.5 Summary 147

6. CHAPTER VI: THESIS SUMMARY 148 - 153

References 154 - 166

Annexure I 167

Annexure II 168

Annexure III 169

Annexure IV 170

Annexure V 172

iv

Pulmonary function assessment through non-invasive techniques-effects of exposure to air pollution