Health Risk Assessment of Informal Food Vendors: A Comparative Study in Johannesburg, South Africa.

According to the best of our knowledge, there are no critical studies to date about associations between the work environment and prevalence of respiratory diseases and their symptoms among urban informal vendors in South Africa. This study followed a risk assessment methodology to assess the risks associated with the occurrence of respiratory health problems among 617 indoor and outdoor market vendors in the inner city of Johannesburg, South Africa. A walkthrough survey using a checklist was conducted in 16 Markets for identification of respiratory risk factors and description of sanitary conditions. Face-to-face interviews were conducted amongst informal food vendors using a previously validated questionnaire to collect information on demographics and occupational and respiratory health. In addition, a single day area air pollution monitoring of PM 2.5 , SO 2 , NO 2 , CO, and CO 2 was conducted in two stalls (indoor and outdoor). The Chi-squared test of association and frequency distribution were used to analyse data. Female vendors aged between 30 to 39 years dominated the trade. The results revealed that a majority of the vendors' work shifts are longer than the recommended eight hours per day (73%), six to seven days per week (90%), and most of them have been working for six to ten years (41%). Poor sanitary conditions were observed in 75% of the markets. The concentrations of air pollutants at the outdoor markets were much greater than those in the indoor markets. All air pollution concentrations were below the recommended national and international standards. The risk of outdoor vendors developing any symptoms were extremely greater than those of indoor vendors, especially cooking vendors. Upper respiratory symptoms were the highest amongst the vendors. The results demonstrated a significant 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, and using of a mask, and the upper respiratory symptoms. Based on the findings, there is a need for formalization of the trade, improvement in infrastructure, respiratory health care assessments, and sustainable educational programs.