The EPA is ignoring the growing evidence that ethanol increases ozone pollution. Every increase in ethanol use as fuel will increases the amount of ozone pollution in the United States. This is one of the times where regardless of a persons views on global warming, the pollution effects of ethanol are real and need to be taken into account.
Ozone is one of the most more hazardous pollutants that is regularly produced by emissions. It is so corrosive that it will degrade stainless steel in periods of less than a year. The OSHA limit for job exposure is 100 ppb for an 8 hour day. At 1 ppm (1,000 ppb) coughing starts and a person will have difficulty breathing. Once it reaches 2 ppm (2,000 ppb) it will cause watering eyes, decreased pulse rate and blood pressure and potentially severe coughing. Levels as low as 40 ppb can cause problems for people that are sensitive (asthma or other respiratory problems). Worldwide the most commonly accepted limits are 60 ppb. It is also possible that lung cancer is associated with increased levels of ozone pollution (NEJM).
I work with ozone on a daily basis for my job and I understand the safety precautions that are needed to safely work with ozone. I have seen the stainless steel piping that is pitted and chewed up by flowing ozone through it at small concentrations. Ozone is truly nasty stuff. Reducing ozone is important for the environment. All forms of life suffer when ozone concentrations are elevated.
The EPA considers ozone as one of the primary pollutants that needs to be reduced. How to reduce it is where the problems arise. As most people are well aware there is a current push for renewable fuels and ethanol is synonymous with renewable fuel. The problem is that ethanol also increases ozone pollution. In study after study the direct comparison shows that ethanol results in more ozone pollution than gasoline.
The difference can be large. The higher the ethanol content in the fuel the more ozone that is produced. It is not a direct emission, but a multiple step reaction of volatile organic compounds (VOC) or nitrogen oxides (NOx). Adding any amount of ethanol to gasoline increases the content of VOC’s in the car emissions. The higher the ethanol content the more VOC’s that are released into the atmosphere.
These VOC’s include formaldehyde, acetaldehyde, 1,3-butadiene, benzene and PAN. All of these VOC’s are directly unhealthy for humans, but they also generate ozone when they decompose in the atmosphere. In all situations these direct emissions result in higher ozone concentrations. Ethanol is more volatile than gasoline and oxidizing (burning) ethanol forms the aldehyde. Gasoline has no such direct conversion to the aldehyde structure.
This can be seen in the large cities of Brazil. In Brazil sugar cane is used to produce ethanol fuel. The blends there use more ethanol than anywhere else at the moment and they are seeing the pollution effects already. The VOC’s are present in higher concentrations than would typically be found if gasoline were used. The study by (Ginnebaugh, et al 2010) found that the concentrations of acetaldehyde, formaldehyde and PAN are markedly higher as a result of the ethanol fuels that are being used. Ethanol causes more pollution than gasoline.
The studies show even worse news for the United States and any climate that is colder than Brazil (Europe, China, Japan). In colder climates the pollution difference is even greater with ethanol. Pure ethanol cannot be used in cold climates for reasons unrelated to pollution, but the highest concentration that could be used (85% ethanol, called E85) shows large increases in final ozone pollution over gasoline.
In a cold climate E85 would produce 40 ppb higher ozone pollution than gasoline (Ginnebaugh, et al 2010). Switching to high ethanol blends would increase ozone pollution by almost 100% in colder climates. The difference in final emissions of 80 ppb to 40 ppm. High ethanol blends produce emissions HIGHER than the EPA allowable limits.
The worst case scenario would be in the spring and fall when the air warms up in the afternoon, but the fuel in the gas tank would remain cold. In that situation ethanol blends would cause the highest increases in ozone pollution. Higher ozone would also be an indicator that the other reactive hydrocarbons would also be present in higher concentrations in such situations.
In all situations ethanol causes higher levels of hazardous pollution. It is worse for plants, animals and humans. It is worse for the environment as a whole. Despite the consistent science that shows the hazards of ethanol, the EPA considers it one of the solutions to ozone pollution. That is correct, the document from the EPA lists ethanol as one of the future alternative fuels that will help reduce future ozone pollution. They completely ignore the science that indicates that ethanol will increase ozone pollution.
The drive for an alternative and renewable energy source has derailed the scientific facts about the hazards that ethanol poses to the public as a whole. The EPA states that reducing ozone pollution is an important goal, but they continue to support ethanol as a solution to that problem. I will not speculate to the politics that drives this view, but it is scientifically unsound. The only pollution benefit is reduced carbon monoxide pollution.
People often confuse the effects of true pollution and the debate about global warming. Ethanol causes more hazardous pollution than gasoline. It is simply bad for the environment. It should not be used as a fuel. There is the potential that as a slight (<1%) additive it would benefit carbon monoxide emissions without causing the other problems, but it should be limited at most to a slight additive. Anything more than that is burden, regardless of the ethanol source.
I am a strong proponent of renewable energy. The long carbon chain oils that can be produced from algae at ~ $80/bbl are very promising. The oils produced in that manner can be used as bio-diesel and there is even potential of blending it with gasoline for car usage. These vegetable type oils will not cause the pollution that ethanol does, they will not decrease fuel efficiency the way ethanol does and they will not compete with food crops the way ethanol does. It is also fully renewable and far more efficient than any crop (1st or 2nd generation type process). More work is needed in development of this, but projects like this will be very beneficial in the long run.