What is more toxic - gasoline or gasoline exhaust?

[Simfish InquilineKea]

And how do the relative chemical compositions compare with each other? Is exhaust "richer" in particulate matter?

Also - I'm extremely interested about gasoline toxicity - and have found myself quite frustrated at the few replies I've gotten by cross-posting a similar question on multiple forums (and with my relatively fruitless google searches - which have yielded much useful information, but not enough). I tend to be more concerned with chronic effects (like cancer) than acute ones, so substances like carbon monoxide and hydrogen sulfide tend to bother me less (as they don't bioaccumulate or damage DNA) than others. So I'm trying to find the best resources + places to ask questions. I've gone so far as e-mailing professors in toxiciology departments - with little avail.

[freeztar]

Tell us what you have discovered so far.

 

In general though, when you burn substances, you generally end up with new substances that are more toxic than the original substance (tobacco for example).

 

Have a look here:

http://www.arb.ca.gov/research/diesel/dpm_draft_3-01-06.pdf

[Simfish InquilineKea]

A lot of what I'm getting is the comparison of effects between diesel and gasoline - which isn't what I'm looking for - as I live in a region where almost everyone uses gasoline. But maybe diesel is used more for some applications? (like How Diesel Exhaust Affects Your Brain : Gas 2.0)

 

http://www.gwu.edu/~macche/EOHtutorial/EOHStudents/Gasoline.pdf is very interesting - it really shows how incomplete the data is at this point. It also seems to be on pure gasoline - I'd expect particulate matter pollution to be worse in exhaust gases.

 

Fil's Auto Corner: Gasoline FAQ is also interesting

 

Gasoline Fact Sheet : again, incomplete data

 

Cancer incidence in urban bus drivers and tramway employees: a retrospective cohort study -- Soll-Johanning et al. 55 (9): 594 -- Occupational and Environmental Medicine : Danish bus drivers have slightly increased cancer risks.

 

Of course the research on extended exposure to pollution (like PMs, ozone, etc) => adverse health effects is well documented. But hydrocarbons don't seem to be a major component of adverse health effects in background air pollution

 

Actually neurotoxicity may also be a concern on top of potential carcinogenicity.

[modest]

Have you tried the MSDS (Material Safety Data Sheet) for Gasoline?

 

IARC has determined that gasoline and gasoline exhaust are possibly carcinogenic in humans. Inhalation exposure to completely vaporized unleaded gasoline caused kidney cancers in male rats and liver tumors in female mice. The U.S. EPA has determined that the male kidney tumors are species-specific and are irrelevant for human health risk assessment. The significance of the tumors seen in female mice is not known. Exposure to light hydrocarbons in the same boiling range as this product has been associated in animal studies with effects to the central and peripheral nervous systems, liver, and kidneys. The significance of these animal models to predict similar human response to gasoline is uncertain.

 

It also has some harsh words on benzene:

 

This product contains benzene. Human health studies indicate that prolonged and/or repeated overexposure to benzene may cause damage to the blood-forming system (particularly bone marrow), and serious blood disorders such as aplastic anemia and leukemia. Benzene is listed as a human carcinogen by the NTP, IARC, OSHA and ACGIH.

 

And wikipedia has some info on the health effects of benzene.

 

Actually, this has me thinking the best way to get detailed info might be to look at the ingredients of gasoline (the MSTS lists them) and research them individually:

 

[math]\begin{array}{|c||c|} ingredient & percent \\

\hline

\textrm{Gasoline}&\textrm{100}\\

\textrm{Benzene}&0.1 - 4.9\\

\mathrm{n-Butane}&<10\\

\mathrm{Ethyl Alcohol}&0 - 10\\

\textrm{Ethyl benzene}&< 3\\

\mathrm{n-Hexane}&0.5 \textrm{ to } 4\\

\mathrm{Methyl-tertiary butyl ether}&0 \textrm{ to } 15.0\\

\mathrm{Tertiary-amyl methyl ether}&0 \textrm{ to } 17.2\\

\textrm{Toluene}&1 - 25\\

\mathrm{1,2,4- Trimethylbenzene}&< 6\\

\mathrm{Xylene, mixed isomers}&1 - 15\\

\end{array}[/math]

 

-modest

[Simfish InquilineKea]

Ah, thanks for the table. That was useful. But doesn't gasoline oftentimes contain impurities?

[modest]

Ah, thanks for the table. That was useful. But doesn't gasoline oftentimes contain impurities?

 

No problem - and yes, those are the impurities. Anything that's not a hydrocarbon is an additive/impurity.

 

There are a few more ingredients listed in the MSDS I linked in my last post that are not common to all gasoline but are rather submitted by some specific manufacturer. But, the ones in the table above are mostly what is common to all gasoline - impurities and all.

 

-modest

[Simfish InquilineKea]

hm, I would expect more impurities (as gasoline composition does vary from place to place, doesn't it? - also - impurities aren't consistent) What I'm most curious about - which is what my topic question asks - is how do the exhaust gases compare in composition to the pure gases?

[modest]

hm, I would expect more impurities (as gasoline composition does vary from place to place, doesn't it?

 

Like I said, there are a few more listed in the MSDS that are not common to all gasoline but are manufacturer specific. Lead would be a big one. Leaded gasoline still exists and the health consequences of lead are very well known.

 

is how do the exhaust gases compare in composition to the pure gases?

 

The most obvious decomposition products for gasoline are carbon monoxide ([CE]CO[/CE]), carbon dioxide ([ce]CO_2[/CE]), and water ([ce]H_2O[/CE]).

 

But, I would imagine there are others such as oxides of nitrogen and sulfur. The most dangerous is clearly carbon monoxide which can kill a person very quickly. Sulfur dioxide also isn't a good thing to be breathing. I'll try and find a list of the decomposition products as I'm just kind of guessing at these.

 

Also - any one of the ingredients listed in the MSDS and the table above should be considered present in the exhaust. In other words: the exhaust is going to have benzene.

 

-modest

[Michaelangelica]

A lot of people are getting worried about fine particle Pollution/matter in Diesel

See the thread "We need a trillion more indoor plants" for some links on this

 

Lead in Gasoline is of course a big problem in many parts of the world.

It is especially toxic to young people.

[modest]

A lot of people are getting worried about fine particle Pollution/matter in Diesel

See the thread "We need a trillion more indoor plants" for some links on this

 

Lead in Gasoline is of course a big problem in many parts of the world.

It is especially toxic to young people.

 

I've always wondered how Roman (the city of the empire) kids could grow up without anemia and a bunch of other things wrong with them when all their pipes were lead.

 

I'll try and find a list of the decomposition products as I'm just kind of guessing at these.

 

The best I could find is here. Which lists these:

• Carbon monoxide (CO)
  
• Aldehyde
  
• Oxides of nitrogen (nitrogen dioxide, nitrogen oxide)
  
• Gaseous hydrocarbons
  
• Sulfur dioxide (SO2)
  
• Ammonia, hydrogen cyanide, hydrogen sulfide
  
• Absorbed hydrocarbons on particulates
  

 

Nitrogen dioxide and sulfur dioxide are both very bad for a person as is of course hydrogen sulfide and hydrogen cyanide - hydrogen sulfide is used for suicide and hydrogen cyanide is used as a chemical weapon. Apparently - yeah - keep your kids away from gasoline exhaust :Exclamati

 

-modest

[Michaelangelica]

I've always wondered how Roman (the city of the empire) kids could grow up without anemia and a bunch of other things wrong with them when all their pipes were lead.

I don't think they did

The nose, however, has a direct connection to the brain.

 

 

 

Some health authorities here are trying to reduce the amount of inhaled gasoline while filling your tank

 

In some stupid youth groups petrol sniffing is a recreational activity.

Authorities are trying to change the composition of petrol so it is less harmful ("Opal"? in NT, Oz)