Abstract
Background: Many people have turned to informal jobs, such as street trade opportunities in large cities, as a result of South Africa's rising overall unemployment rate. However, in the same cities, air pollution is a problem. Poor air quality is a public health concern and a key contributor to morbidity and excess mortality. Additionally, research has shown that informal trading is less regulated than the formal trading industry. Although it is well established that cooking emissions are a significant contributor to indoor air pollution, less is known about the environmental effects of outdoor cooking, specifically the relative importance of various cooking fuels. This analytical cross-sectional study was conducted in the inner city of Johannesburg. This study aimed at using quantitative methods to assess the respiratory health risks of indoor and outdoor informal food street vendors and their impact on vendors’ respiratory health.
Methods: This study was designed according to the steps of the human health risk assessment. A walk-through survey was conducted in 16 vendor markets using a checklist for a better description of the markets and the identification of related health risks. Area or static air sampling was conducted for PM2.5, CO, CO2, NO2, and SO2, and personal PM2.5 sampling. A face-to-face interview of the 617 vendors was done using a structured researcher-administered questionnaire comprising of demographic information, operational characteristics, and self-reported respiratory symptoms and diseases of the last 12 months. For risk characterisation, the air pollutants concentrations were compared to national and international standards. The SPSS tool was used for analysis. Estimation of the prevalence of respiratory symptoms and diseases in relation to the numbers of the population was reported in frequencies. The chi-square test was conducted between the demographic and operational characteristics and the respiratory symptoms and P-values were considered significant at p < 0.05. Additionally, the study included developing an evidence-based model to create healthy workplaces for informal vendors.
Results: South African vendors accounted for 54%, compared to 46% who were non-South Africans. Female vendors (55%) dominated the trade, with the most vendors at the age of 30 and 39 years (44%); and 63% of the informal vendors had a secondary
level of education. The majority of the vendors have worked between 6 and 10 years (42%), 6 to 7 days a week (90%), and over the recommended 8-hours a day (73%). Fifty-six percent were cooking vendors and 44% were non-cooking vendors. There were poor sanitary conditions observed in 12 of the markets (75%) and only 4 (25%) of the markets were in a good sanitary condition. The concentrations of air pollutants at the outdoor markets were much greater than those in the indoor markets; with the most exposed being from Homogeneous Exposure Group (HEG)Three which are outdoor vendors who cook using open fire. Furthermore, increased exposure was seen in the spring and winter seasons as compared to the summer and autumn seasons. All air pollution concentrations conformed to the recommended national and international standards. The clinical presentation was dominated by upper airway symptoms; cold (43%), sore throat (42%), and nasal congestion (40%). The most reported symptoms in the upper and lower symptoms category were cold (43%) and cough (39%) respectively. Out of the nine vendors with chronic respiratory illness, bronchial asthma (56%) was the most reported. The results demonstrated a positive association between work-related risk factors such as type of work, location, duration, type of cooking fuel or heat, vendor training, frequency of hand hygiene practice, use of mask, and upper respiratory symptoms. Incorrect RPE (surgical and cloth masks) was used which provides ineffective protection for the air pollutants. The proposed healthy workplace management model had five main components: reviewing informal vendor legislation; redesigning designated vending or trading sites; space allocation and occupancy; training and developing the skills of vendors; and, finally, ensuring the sustainability of vending sites and the health of vendors.
Conclusion: Those who work at outdoor markets, especially cooking vendors, had an increased risk of developing respiratory health problems. It is possible to conclude that these excess respiratory and other health symptoms are very likely due to traffic-related air pollutants and the use of dirty cooking fuels in outdoor markets. There is a need for improvement in infrastructure and continuous air sampling assessment in these markets given the high risk of pollution in this industrial city. In addition, the trade needs to be formalized with the participation of all pertinent stakeholders.