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1
Issues in Global Health: An Investigation of Respiratory Health Effects of Air Pollution in
Durban, South Africa
Thomas Robins, MD, MPH
2
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?
3
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?
4
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
5
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)
6
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
7
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
8
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
9
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
10
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
11
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)
14
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?
15
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?
16
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.
17
Durban Metro Area, SO2 Monitoring Sites
Air Quality Monitoring at School
Inside Monitoring Van
20
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
21
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
22
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
23
Bi-Hourly Symptom Activity Log
24
AirWatch Lung Function Monitoring Device
25
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.
26
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
27
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
28
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
29
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
30
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
31
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.
32
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
33
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
34
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
35
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