Development of a regulatory mechanism for the control of exposure to diesel particulate matter (DPM) in the South African mining industry

Abstract

The International Agency for Research on Cancer (IARC) in June 2012 declared diesel exhaust to be a Group 1 Human carcinogen. Currently in South Africa there are no regulatory mechanism specifically to control exposure to diesel exhaust and particulate matter. The objective of this research report is to develop a regulatory mechanism for the control of exposure to Diesel Particulate Matter (DPM) in the South African Mining Industry The primary methods used during this research were to establish a crude exposure baseline using the NIOSH 5040 method of sampling and analysis for personal exposure. The numbers of samples per occupation at the mines under study were done according to the Mandatory Code of Practice on Airborne Pollutants issued by the DME (now DMR); the sample results were also used to estimate the total carbon to elemental carbon (TC/EC) ratio. The analysis of the development of Occupational Exposure Limits (OELs) and or tailpipe emissions standards was primarily literature based. From the personal samples taken, there were a number of overexposures when compared to current international benchmarks such as the Mine Health and Safety Administration standards in the USA. The processes of developing occupational exposure limits are well defined internationally and the various health impact studies have provided adequate data for the exposure limits to be developed. Recommendations have been made for a phased-in approach to compliance with exposure limits that will be introduced through regulation. Most of the health impact studies tend to indicate that the odds of developing lung cancer at much lower exposures are reduced. The time to lobby for an OEL for exposure to DPM and to introduce tailpipe emissions standards (as necessary e.g. in coalmines) has become urgent. This work concludes that as close to a health based OEL would be Time Weighted Average (8hr) of 0.1 mg/m3 EC, as sampled and analysed through the NIOSH 5040 method.