Kobus,
Answering your question fully requires a lot more expertise than I have at hand. I may know more next year, when I intend to do an article on the dangers of petrol fumes. I believe that there is research that shows clear reductions in blood levels of lead from decreasing lead in petrol in places like Mexico City and it has had a positive impact on health. It is also true that there has been a trade-off in places where large numbers of cars without catalytic converters are running on lead-free petrol with more volatile organic compounds, which has led to increases in smog. Lead is so poisonous, however, that I have not seen any suggestion that this trade-off has actually made people less healthy. More research is required to know whether the particular lead replacement petrol being used in South Africa raises these issues. The replacement of catalytic converters is also a serious issue that deserves some research for an article or a post of its own. But your replacement figures of 60000 to 90000 kms are definitely low. It’s possible that those were for miles, not kilometres, but they still seem a little low. Somewhere over 100000 kms a catalytic converter may need to be replaced.

Don

As far as low sulphur diesel is concerned, I have to concur that fuel companies certainly do not push sales of it. I recently bought a diesel vehicle (VW T5 Kombi) and found that (in the northern suburbs of Cape Town at least) low sulphur diesel is all but unobtainable. It seems as if only BP prominently displays it on their pumps. The attendants at other filling stations just shrug their shoulders when asked about low sulphur diesel (see this article, for instance – http://www.iol.co.za/general/other/lol_container.php?click_id=3027&art_id=vn20060628091226985C646774&set_id=40).

But a more worrying factor (to me at least) is the complete lack of understanding/unwillingness by the authorities (and the populace at large) of the fact that emissions by vehicles running unleaded petrol without using a catalysor are far more dangerous and carcinogenic than that of leaded petrol.

Opposing views abound on the Internet, but it seems to me as if the question regarding the higher toxicity of unleaded petrol is largely ignored or glossed over by most protagonists for it.

I did some research when the change was legislated initially, but did not save the URL’s (a couple are given below).

http://www.ncf.org.za/main.php?include=docs/pr/2005/pr1007.html&menu=menus/media.html
http://www.mg-tabc.org/techn-up/leadfree.htm
http://www.um.edu.mt/pub/petrollead.html

Unfortunately I do not have the necessary knowledge to make an informed decision, so would appreciate it if you could comment on it (my apologies if you have already done so, but I could not find anything on your blog).

I do not have any hard figures, but my gut feel is that in SA (and neighbouring countries) at least 70% of petrol vehicles do not have catalytic converters, which would make the air much more toxic than before.

A couple of questions:

1) Have any studies been done (or are any in progress) as far as you know that have monitored blood lead levels prior to and since the switch to lead-free petrol? And what are the results?

2) Have any studies been made/are underway to test for the effects of the more dangerous pollutants due to the introduction of lead-free petrol? And what are the results?

3) Are there any plans afoot to address the high number of catalytic converter free vehicles? Similarly – I do not think there is any compulsion/requirement that would force people to replace the catalytic converters once it has reached the end of its life (60000 to 90000 km if I remember correctly).

Kind regards

Kobus