1 issues in global health: an investigation of respiratory health effects of air pollution in...

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Issues in Global Health: An Investigation of Respiratory Health Effects of Air Pollution in

Durban, South Africa

Thomas Robins, MD, MPH

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Issues in Global Health: An Investigation of Respiratory Health Effects of Air Pollution in

Durban, South Africa

Some themes to keep in mind during the presentation:

Why are health issues in the developing world important to study?

When and how can effective studies be carried out in challenging situations with limited resources?

How can studies of respiratory morbidity associations with environmental pollution be designed to give valid & useful results?

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Overview of Presentation

Who was involved in the study and how was it funded? What was the purpose of the study? How was the study carried out? What did we learn about:

Pollutant sources and levels?

Current health of the participants?

Health effects of air pollution? What conclusions did we reach? What recommendations do we have?

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Team Of Investigators

University of Natal Faculty of Medicine:

Barry Kistnasamy, MBChB, Dean

Rajen Naidoo, MBChB, Head, Occupational Health Unit

Umesh Lalloo, MBChB, Head, Department of Medicine

Elvis Irusen, MBChB, Department of Medicine (now at University of Stellenbosch)

Caron Jack, Department of Medicine

Prem Ramlutchman, Department of Medicine

Natasha Maistry, Office of the Dean

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Team Of Investigators

Durban Institute of Technology:

Joy Kistnasamy, Lecturer, Environmental Health

Nitasha Baijnath, Environmental Health

University of Michigan, USA:

Thomas G. Robins, MD, MPH, Professor, Environmental Health Sciences

Stuart Batterman, PhD, Professor and Associate Chair, Environmental Health Sciences

Graciela Mentz, PhD, Department of Statistics

Heinrich Amsterdam (visiting from Pentech)

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Collaborators

Settlers Primary Environment Committee

South Durban Community Environmental Alliance

ECOSERV

Ethekwini Municipality Health Department

Ethekwini Municipality Water Department

Dr. Barry Seetharam

Prof. Prakash Jeena

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Funding Sources

groundWork

Ethekwini Municipality Health Department

University of Natal

Durban Institute of Technology

Fogarty International Center, USA

University of Michigan, USA

Medical Research Council

Engen

SAPREF

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Background

A legacy of Apartheid era policies: lack of ‘zoning’ of industrial development

South Durban has two large international refineries, a paper mill, an international airport, a chemical tank farm, a number of landfill sites and various mills, processing and manufacturing industries

All in close proximity to residential and recreational areas

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Background

Long history of community groups raising concerns: South Durban Community Environmental Alliance (SDCEA); at the school, Settlers Primary Environmental Committee (SPEC)

Specific responses of governmental agencies & industries

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Background (Cont.)

SO2 Committee (‘tripartite’)

continuous monitoring of SO2 at the school since June 2000

continuous monitoring of oxides of nitrogen, carbon monoxide, total reduced sulfurs, and PM10 since October 2000

No previous studies of exposure-health outcome associations

Current government request for tenders for larger study: ZAR 6 million

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What Was The Main Purpose Of The Study?

To look at whether air pollution is causing breathing problems amongst students and teachers at the School

Settlers Primary School

Settlers Primary School (Cont)

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Research Questions

How many learners and teachers at the Settlers School have chronic respiratory symptoms and conditions, including asthma?

Do air pollutants measured at the Settlers School affect respiratory symptoms and breathing function among students and teachers?

Do those with asthma or other respiratory diseases suffer more from air pollution?

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Research Questions (continued)

Which pollutants cause these health problems?

What are the sources of these pollutants?

What steps should be taken to improve the health of students & teachers? Of the larger community?

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How Was The Study Carried Out?

Exposure assessment Levels in the air of several pollutants

were measured on the school grounds during an 18-day period, 19 April – 6 May, 2001.

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Durban Metro Area, SO2 Monitoring Sites

Air Quality Monitoring at School

Inside Monitoring Van

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Monitored Air Pollutants

Pollutant Frequency Method

Sulfur Dioxide (SO2) Continuous (min) UV absorption

Continuous (3 min)

Total Reduced Sulfur (TRS) Continuous (3 min)Scrub, conversion, UV absorption

Particulate Matter (PM10) Continuous (min) TEOM

Integrated (24 hr)Filter collection, gravimetric

Nitrogen Oxides (NO NO2 NOx) Continuous (min) Chemiluminescence

Carbon Monoxide ContinouusCorrelation, IR absorption

Volatile Organic CompoundsIntegrated (2-16 hr)

TO-17, absorbents, GC-MS

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How was the study carried out? Recruitment of Participants. All teachers, all students in

grades 3 and 6, and some students in grades 5 and 7, were invited to participate in the study. More than 90% of those invited did participate; the

participants included 248 students and 25 teachers. The baseline health of the participants was looked at by

using: parent and child interviews breathing function tests including a special test – called

methacholine challenge – to look for asthma

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How was the study carried out?

Also, participants were asked to complete: each evening at home a daily diary of

symptoms every two hours while at school:

a symptom log blow into a handheld monitor which

measures breathing function

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Bi-Hourly Symptom Activity Log

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AirWatch Lung Function Monitoring Device

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How was the study carried out?

The relationships between exposure to air pollutants such as sulphur dioxide (SO2), particles (PM10), and nitrogen dioxide (NO2) and symptoms and breathing function while at school were looked at.

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Monthly Trends of Sulfur Dioxide at the Settlers School

0

5

10

15

20

25

30

35

Jun

eJu

lyA

ug

Sep

tO

ctN

ov

Dec

Jan

Feb

Mar

Ap

ril

May

Jun

eJu

lyA

ug

Sep

tO

ctN

ov

2000 Month 2001

Co

nce

ntr

atio

n (

pp

b)

What did we learn?: Exposure Assessment

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Long term Pollutant Trends – Sulfur Dioxide

0

5

10

15

20

25

30

35

1989 1991 1993 1995 1997 1999 2001

Year

SO

2 C

once

ntra

tion

(ppb

)

Settlers / Merewent Wentworth South Works

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Daily Trends of SO2 During Study Period

0

5

10

15

20

4/17 4/19 4/21 4/23 4/25 4/27 4/29 5/1 5/3 5/5Study Day (month/day)

Con

cent

ratio

n (p

pb)

24-hr mean

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Diurnal Trends of SO2 During Study Period

0

5

10

15

20

0 2 4 6 8 10 12 14 16 18 20 22 24Hour of Day

Con

cent

ratio

n (p

pb)

15-min mean

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Comparison of Measured Pollutants to Standards & Guidelines

Sulphur Dioxide [ppb] DEAT Guidelines 100 30 SO2 Steering Committee 57 15 US NAAQS 140 30 WHO 48 19 Settlers School Study 20 (1) 8 (2)

PM 10 [ug/m3] DEAT Guidelines 180 60 US NAAQS 150 50 WHO 150 50 Settlers School Study 55 (1) 29 (2)

(1) maximum 24-hr average during study period(2) average during study period

Pollutant & Standard/GuidelineMaximum 24 hr

Average Annual Average

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Summary of Pollutant Measurements We focused on monitoring at the Settlers School for the study

period in April – May, 2001.

Pollutant levels vary by season, time-of-day, location and pollutant. Monitoring at the school provides only an approximate indication of pollutant exposure.

At the Settlers School during the study period, pollutant levels were below guideline levels

Historically, pollutants have exceeded guideline levels

Looking at the long term trends, levels appear to be decreasing for one pollutant, sulfur dioxide.

Long term data on other pollutants is not available.

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Figure 19. Distribution of asthma severity from parent baseline interview among students in grades 3 and 6.

(n=147 students)

26.5

47.6

15.0

10.9

Moderate to severe asthma mild persistent mild intermittent none

What did we learn?: Health Status of Participants

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Figure 20. Student asthma severity from the baseline parent interview by various

demographic variables among students in grades 3 and 6. (Part I) (average n=143 students)

15.9

7.1

13.28.8

0.0

15.9 14.318.7

8.8

16.7

27.0 26.228.6

14.7

33.3

41.3

52.4

39.6

67.6

50.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

3rd. 6th. Merebank Umlazi Elsew here

Grade Home Location

Moderate to severe asthma mild persistent mild intermittent none

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Figure 21. Student asthma severity from the baseline parent interview by various

demographic variables among students in grades 3 and 6. (Part II) (average n=162 students)

11.9 11.0 11.1 9.6

16.7

10.0

4.3

15.3 16.4 14.8 14.5

5.6

14.4

21.7

28.8

23.3 24.127.7 27.8 26.7 26.1

44.1

49.3 50.048.2

50.0 48.9 47.8

0.0

10.0

20.0

30.0

40.0

50.0

60.0

Male Female No Y es <R5000 R5001-R50000 >R50000

Gender Number of Smokers in Household A nnual Family Income

Moderate to severe asthma mild persistent mild intermittent none

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Figure 23. Distribution of methacholine challenge test results among students in

grades 3 and 6.(n=204 students).

Degree of Airway Hyperreactivity

28.9

18.7

31.6

20.9

marked probable possible none