English: Economic and domestic activities have been causing a profound deterioration of air quality in developed and developing countries. The health problems arising from air pollution, both indoor and outdoor, have become apparent which result in welfare losses in society such as increased workdays lost and high health cost. The empirical work on welfare losses as a result of air pollution in South Africa has focussed only on urban settlements, hence the need of this study. The main objective of this study was to explore the economic impact of air pollution in two townships of Mangaung metro municipality. The study was conducted in Phahameng and Rocklands areas. The sampling technique used was the stratified random sampling technique. Data was collected through a Contingent Valuation (CV) questionnaire. The 26 questions in the questionnaire were compiled through interaction with knowledgeable individuals and completed via face-to-face interviews. A total sample of 300 households was surveyed with 111 questionnaires administered in Phahameng and 189 in Rocklands. The mitigating cost and the number of workdays lost as a result of an episode of air pollution related illness was estimates from the survey. Mitigating cost is measured as the total cost incurred (include consultation fee, cost of medication, hospitalisation and transportation fees) as a result of treating the last episode (prior to interview) of air pollution related ailments. Workdays lost is measured as the number of days lost for the last episode (prior to interview) of ailment related to air pollution. For employed respondents, it is measured as number of days not able to go to place of work; for self-employed or unemployed respondents, it is measured as the number of days not able to perform daily routine or activities. For respondents that are studying, it is measured as days absent from school. The factors influencing these economic parameters (mitigating cost and workdays lost) were explored using Ordinary Least Square (OLS) Regression Model. The Contingent Valuation questions measured welfare losses by asking a hypothetical question regarding household willingness to pay for improved air quality.Willingness to pay for improved air quality was determined through a double bounded iterative bidding. Based on the pilot survey and evaluation of previous studies, a starting bid of R100 was chosen. The mean willingness to pay per household was estimated from the upper and lower bound amount given by each household respondent. Three steps were taken to evaluate the respondents’ willingness to pay for improved air quality. Firstly, the Cragg’s Model was used to determine if the choice to pay and the amount that will be paid for improved air quality is onedecision or two-decisions. A Probit Model was fitted to evaluate the factors that influence the willingness to pay decision (whether or not to pay). Lastly, a Truncated Regression Model was fitted to determine the factors that determine the amount that will be paid for improved air quality as indicated by those who are willing to pay. The empirical results revealed that the mean workdays lost and mitigating cost as a result of illness associated with air pollution in both study areas is 3.43days and R112.27 respectively. Health, duration of illness, age, district (Phahameng or Rocklands), mitigating cost and number of visits to see a doctor or to pharmacy for treatment were found to be the principal factor influencing workdays lost. High income level, duration of illness, district (Phahameng or Rocklands), ailment (episode of air pollution related ailment), workdays lost, treatment methods and unemployed were found to be the principal factors influencing mitigating cost. The mean willingness to pay per household for improved air quality on a monthly basis from both study areas is R110.59. The Cragg’s Model showed that the choice to pay for improved air quality and the amount to be paid is two separate decisions and should thus be modelled as such. Results from the Probit Model shows that education and ailment (episode of air pollution related ailment) are the principal factors that influence the decision of whether or not to pay. The Truncated Regression Model indicated that the decision on how much to pay is determined by education and high income. The conclusion from the study is that the impact of air pollution should be seen beyond the adverse health effect it poses. Air pollution can be reduced by creating environmental awareness not only in the study areas but in South Africa.
Afrikaans: Ekonomiese en huishoudelike aktiwiteite het ‘n geweldige agteruitgang in die gehalte van lug oral in ontwikkelde en ontwikkelende lande veroorsaak. Dit blyk dat gesondheidsprobleme as gevolg van lugbesoedeling, sowel binneshuis as buitenshuis, groot maatskaplike verliese veroorsaak, soos byvoorbeeld verhoogde aantal werksdae wat verlore gaan en hoë gesondheidsuitgawes. Tot dusver het die empiriese werk gedoen op maatskaplike verliese as gevolg van lugbesoedeling in Suid-Afrika slegs op stedelike gebiede gefokus, vandaar dan die noodsaaklikheid van hierdie studie. Die hoofdoelwit van die studie was navorsing oor die ekonomiese impak van lugbesoedeling in twee gebiede binne die Mangaung Metro Munisipaliteit. Die studie is binne Phahameng en Rocklands-gebiede uitgevoer. Die proefnemingstegniek wat vir die studie gebruik is, was die stratigrafiese willekeurige proefnemingstegniek. Inligting is by wyse van ‘n vraelys ingewin. Die 26 vrae vervat in die vraelys is deur middel vaninteraksie met kundige persone opgestel en met behulp van individuele onderhoude vervolmaak. ‘n Totaal van 300 huishoudings is gedurende die proef bestudeer, met 111 vraelyste in Phahameng en 189 in Rocklands voltooi. Die Versagtings koste (“mitigating cost”) en die aantal werksdae wat verlore gaan as gevolg van lugbesoedeling-verwante siektetoestande was beramings soos uit die studie verkry. Versagtings koste word bereken as die totale uitgawe aangegaan (insluitende konsultasiefooie, koste van medisyne, hospitalisasie en vervoerkoste) as gevolg van behandeling van ‘n laaste geval (voor die onderhoud) van ‘n lugbesoedeling-verwante siektetoestand. Verlore werksdae word bereken as die aantal dae wat verlore gegaan het tydens die laaste periode van afwesigheid (voor die onderhoud) as gevolg van ‘n lugbesoedeling-verwante siektetoestand. Sover dit werkende respondente betref, is dit bereken op die aantal dae wat hulle nie in staat was om na hul werksplekke te gaan nie; vir persone in eie diens of werklose respondente, is dit bereken as die aantal dae waar sulke persone nie in staat was om daaglikse take of aktiwiteite uit te voer nie. Vir studerende respondente is die berekening gedoen op die aantal dae van afwesigheid van skool. Faktore wat hierdie ekonomiese parameters beïnvloed, (versagtings koste en verlore werksdae) is met behulp van die “Ordinary Least Square (OLS)” Regressiemodel ondersoek. Die Gebeurlikheids analise -vrae het maatskaplike verliese bereken deur middel van die hipotetiese vraag oor die bereidwilligheid, al dan nie, van ‘n huishouding om vir beter lugkwaliteit te betaal. Sodanige bereidwilligheid om te betaal vir beter lugkwaliteit is deur middel van ‘n dubbelbindende herhalende bod (“double bounded iterative bidding”) bepaal. ‘n Aanvangsbod van R100, gebaseer op die loodsproefneming en die beramings verkry vanuit vorige studies, is gekies. Die gesamentlike bereidwilligheid om te betaal per huishouding, is bereken deur middel van die boonste en onderste bod wat deur elke respondent in sodanige huishouding verskaf is. Drie stappe om respondente se gewilligheid om te betaal vir beter lugkwaliteit te verklaar, is gevolg: Eerstens is die Cragg’s Model gebruik om te bepaal of die keuse om te betaal, sowel as die bedrag betaalbaar vir verbeterde lugkwalitieit, ‘n een-besluit of ‘n twee-besluit beslissing was. ‘n “Probit” model is gebruik om die faktore te bepaal wat die besluit om te betaal, al dan nie, beïnvloed. Laastens is ‘n “Truncated” Regressiemodel aangewend om die faktore te bepaal wat die bedrag betaalbaar deur respondente vir beter lugkwalitieit, beinvloed. Die empiriese resultate het bewys dat die gemiddelde verlore werksdae en versagtings koste as gevolg van lugbesoedeling-verwante siektes in beide studie-areas 3.43dae en R112.27 onderskeidelik was. Gesondheid, duur van siekte, ouderdom, distrik (Phahameng of Rocklands), versagtings koste en aantal doktersafsprake of besoek aan ‘n apteek vir behandeling, was die hoofoorsaak van verlore werksdae. Hoë inkomstevlakke, duur van siekte, distrik (Phahameng of Rocklands), aard van siekte (voorval van lugbesoedeling-verwante siekte), verlore werksdae, behandeling en werkloosheid was die hoofoorsake wat die versagtings koste beïnvloed het. Die gemiddelde mate van bereidwilligheid van ‘n huishouding om op ‘n maandelikse basis te betaal vir beter lugkwaliteit in beide areas, was R110.59. Die Cragg’s Model het aangedui dat die keuse om te betaal vir beter lugkwaliteit, sowel as die hoeveelheid betaalbaar, is twee afsonderlike besluite en behoort so aangedui te word in die model. Resultate van die Probit Model het aangedui dat opvoeding en siekte (voorval van lugbesoedeling-verwante siekte) die hoofoorsake van die besluit om te betaal, al dan nie, beïnvloed. Die “Truncated” Regressiemodel het aangedui dat die besluit oor die bedrag betaalbaar, bepaal word deur opvoedingspeil en hoë vlak van inkomste. Die gevolgtrekking verkry uit die studie is dat die invloed van lugbesoedeling verder as die nadelige gesondheidstoestand strek. Lugbesoedeling kán wel beheer word, deur omgewingsbewustheid in die studie-areas, sowel as die hele Suid-Afrika, te kweek.
Correlation between argronomic and environmental phoshorus analyses of selected soils ﻿
Nthejane, 'Mabatho Margaret (University of the Free State, 2012-06)
English: In crop production phosphorus (P) is an essential nutrient for crop growth, and hence P fertilization is necessary to achieve optimum yields. However, this can induces in soil a P concentration which may contributes ...
Site characterisation methodologies for DNAPLs in fractured South African aquifers ﻿