CHAPTER 5: THE RESPIRATORY HEALTH EFFECTS ASSOCIATED WITH
5.3 Materials and methods
This cross-sectional study explores the possible association between PM2.5 and the respiratory health in children residing near the Bisasar Road landfill site in Clare Estate, Durban. This study presents a subset of the main study which amassed and analysed data from a child-health screening questionnaire. From the 157 household that participated in the child-health screening questionnaire, 31 (20%) randomly selected households were revisited to gather PM2.5 samples and respiratory evaluation, of which 23 (15%) agreed to participate. Spirometric data were collected using a portable, electronic spirometer (SCHILLER SP-260, Baar, Switzerland). The details of data collection methods are discussed separately in 5.3.1 and 5.3.2.
5.3.1 PM2.5 sampling
PM2.5 samples from homes were collected from 23 homes for a period of three months (November 2013 to January 2014). A real-time particulate monitor (EPAM-5000, Plaistow, USA) was used for sampling. This instrument uses both nephalometric and the gravimetric principle to measure PM, in this case PM2.5. EPAM-5000 was deployed in the morning between 8am and 10am and was positioned is a living area within the house so that it collect dust where residents spend their time during the day. EPAM-5000 is a highly sensitive real-time particulate monitor designed for ambient and indoor air quality applications. It combines traditional filter techniques with real-time monitoring methods. It uses the principle of near-forward light scattering of infrared radiation to immediately and continuously measure the concentration in µg m-3 of airborne dust particles (Bu-Olayan 2012). Dust sampling was conducted with PM2.5
impactor attached to the EPAM-5000 to allow for the collection of PM2.5.
PM2.5 samples were collected over in 10 min intervals between measurements for a period of 24 hours in each home, with data stored in the EPAM-5000 for later downloading into a computer using its DustComm Pro software. The software was designed to store and analyse data and create print-ready reports. EPAM-5000’s DustComm Pro Software uses a continuous monitoring system to display the minimum, maximum and average concentration values of
PM2.5. These concentration levels are expressed in mg m-3. The converted mean concentration values for mg m-3 to µg m-3 were used to report PM2.5 concentration levels.
5.3.2 Spirometry
The spirometry (lung function testing) was performed by the researcher, who is a trained spirometry technician, on a subset of 23 (13%) of the 181 children (aged 6 – 12 years) who initially participated in child-health screening surveys. According to the NHANES (2008), persons aged 6 to 79 years are eligible to participate in the spirometry component since they lungs are developed enough to perform spirometry. In this study, a pre-screening questionnaire was administered to parents or caregiver before the children could participate. This was done to exclude children who had medical conditions that could put a child in a risk. Such conditions include chest injuries, heart attack, high blood pressure, and respiratory infection (Appendix H). All participating children were assessed at their homes and in the presence of the parents or caregivers. The consent was obtained from parents or caregivers before spirometry was performed. Spirometry was performed in a standing position without a nose-clip using a SCHILLER SP-260. Spirometer was calibrated before it was used and measurements were performed following the American Thoracic Society (1995) guidelines.
Spirograms were used to classify participants as normal, having an obstructive pattern and/or a restrictive pattern. According to NHANES (2008), a low forced vital capacity (FVC) is indicative of a restrictive disorder, and typically these individuals will also have a low forced expiratory volume in one second (FEV1), whilst a low FEV1/FVC% ratio may indicate an obstructive impairment. Predicted percentage of more than 80% for FVC; and FEV1 and FEV1/FVC ratio of greater than 0.7 were considered a cut off level for lung function tests to be normal. These limits are commonly used internationally for categorizing lung function as normal or abnormal. Obstructive lung function was defined as having FEV1 < 80% and FEV1/
FVC < 70% and restrictive lung function was defined as having FEV1 < 80% and FEV1/FVC
> 70% (Global Initiative for Chronic Obstructive Lung Disease 2006).
Spirometry was conducted to establish the lung function patterns of participating children. Each participant performed at least three technically acceptable tests and each individual test was acceptable if it met both acceptability and repeatability criteria. Tests were accepted if the two largest FVC and FEV1 values were reproducible (variation within 5%), otherwise additional
testing was conducted until the acceptance range were achieved (American Thoracic Society 1995). A SCHILLER SP-260 displayed the real time pulmonary test results and provided a clear and comprehensive result analysis. This study considered values of the FVC, FEV1, and the FEV1/FVC ratio to assess the lung pattern in children. SCHILLER SP-260 has data management software for the storage, archiving and instant diagnosis of recordings. Hence, the results from the spirometer were automatically stored in a computer through its PC Spirometry software (SDS-104).
5.3.3 Ethical approval
Prior to the data collection process, the researcher submitted an ethical clearance application for approval by the University of KwaZulu-Natal. Ethical approval for the study was secured from the Biomedical Research Ethics Committee (Ethical clearance number: BE201/11). This study adhered to ethical principles throughout, to protect the rights of the participants. Neuman (1997) mentions that the rights of the participants include: the right not to be harmed, the right to self-determination; the right to privacy; and the right to obtain services. Furthermore, he mentions that these rights are related to: the rights to maintain self-respect and dignity, the right to remain anonymous, and the right to have confidential material remain confidential.
The researcher maintained the rights outlined here.
5.3.3.1 Protection of privacy
The data collectors observed a strict ethical adherence to protect participants’ confidentiality, meaning that data provided were not made accessible to anyone who was not directly involved in the study. The clarification on how data were collected, analysed and stored was made known to participants. Data collectors warranted that interviews were conducted in a private/conducive place to participants. In the event of disruptions, the interviewee stopped the interview until the cause of the disturbance was seen to, and only then was the interview continued.
5.3.3.2 Informed consent
The guardians/informants were asked to read and sign the informed-consent form confirming that they voluntarily participated in the study after they had been advised about its purpose, the
type of information being collected, and how that information would be used. The guardians/informants retained a signed copy of the informed consent forms.
5.3.3.3 Voluntary participation
Participants were informed that participation in the study was voluntary, and that failure to participate in the study or a withdrawal of consent at any stage was not going to be penalised in any way. Participants were informed that they were not obliged to answer any questions they did not wish to.
5.3.3.4 Avoidance of harm
The study did not place any participant in a potentially harmful situation, whether physically, emotionally, socially, politically, economically, and/or psychologically. All issues were discussed with sensitivity. The times and localities of the interviews was taken into consideration in order to ensure confidentiality. Guardians and participants were given the researcher’s contact details and were instructed to call if they felt the need to debrief after the interview had taken place.