Indoor and outdoor particulate matter concentrations on the Mpumalanga highveld – A case study

The household combustion of solid fuels, for the purpose of heating and cooking, is an activity practiced by many people in South Africa. Air pollution caused by the combustion of solid fuels in households has a significant influence on public health. People mostaffected are those considered to be the poorest, living in low-income settlements, where burning solid fuel is the primary source of energy. Insufficient data has been collected in South Africa to quantify the concentrations of particulate emissions that peopleare exposed to, especially the respirable fraction, associated with the combustion of solid fuels. The aim of this paper is to gain an understanding of the particulate matter (PM) concentrations a person living in a typical household in a low income settlement in theSouth African Highveld is exposed to. It also seeks to demonstrate that the use of solid fuels in the household can lead to indoor air pollution concentrations reaching levels very similar to ambient PM concentrations, which could be well in excess of the NationalAmbient Air Quality Standards, representing a major national public health threat. A mobile monitoring station was used in KwaDela, Mpumalanga to measure both ambient particulate concentrations and meteorological conditions, while a range of dust/particulate monitors were used for indoor and personal particulate concentration measurements. Indoor and personal measurements are limited to the respirable fraction (PM4) as this fraction contributes significantly to the negative health impacts. The sampling for this case study took place from 7-19 August 2014. Highest particulate matter concentrations were evident during the early mornings and the early evenings, when solid fuel burning activities were at their highest. Indoor and personal daily average PM4 concentrations did not exceed the 24h National Ambient PM2.5 Standard of 65 μg/m3 nor did they exceed the 24h National Ambient PM10 Standard of 75 μg/ m3. The outdoor PM2.5 concentrations were found to be below the standards for the duration of the sampling period. The outdoor PM10 concentrations exceeded the standards for one day during the sampling period. Results indicate that, although people in KwaDelamay be exposed to ambient PM concentrations that can be non-compliant to ambient standards, the exposure to indoor air, where solid fuel is burnt, may be detrimental to their health

Modelling, simulation and evaluation of centralised and decentralised food manufacturing scenarios

Current long-rigid centralized supply chains, responsible for high energy consumption and environmental impact, might become outdated in a near future. Many theoretical studies, predicting a shift on companies’ strategical approach to the market based on scaling down and decentralization to reach mass differentiation, can be found in literature. This work demonstrates that the shift on manufacturing paradigm can be studied as an engineering problem. Process system engineering methodology is implemented to develop a modelling tool, capable to generate trusted practical data for common and alternative manufacturing scale scenarios with increasing degree of decentralisation, i.e. Single plant production, Multiple plant production, Distributed Manufacturing, Food Incubator, and Home manufacturing. The tool is used to perform a techno-economic and environmental assessment for three food products of distinct characteristics, namely dry cereal porridge, sandwich bread and ice cream. The processing alternatives are first designed and studied separately for each food, to identify the benefits and tradeoffs associated to decentralised production methods. Variations on economic, social and environmental impact parameters along a wide range of production rates –e.g. 0.01 to 50,000 kg/h– are evaluated, and a UK demand framework is used to check the performance of the alternative production methods in a realistic scenario. A final comparison among the three items is performed to study how each scale differently functions for the production of each food studied. The output of this research is to offer a robust tool that might assist companies in the complex decision between centralized or decentralized manufacturing systems for real market opportunities