ОңТҮстік қазақстан медицина академиясы, хабаршы №4 942, 2021 жыл, том 2



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ОҢТҮСТІК ҚАЗАҚСТАН МЕДИЦИНА АКАДЕМИЯСЫ, ХАБАРШЫ №4(942, 2021 жыл, ТОМ 2 
 
 
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geographic characteristics influence the impact of these air pollutants. Ozone formation e.g. occurs more 
easily during hot weather. Also toxic air pollutants are more evident under hot weather conditions. They can 
be emitted either by the engine exhausts or by evaporation from fuel storage and fuel handling since ethanol 
has high volatility and generally increases evaporative emissions of gaseous hydrocarbons. As opposed to 
this, carbon monoxide is a larger problem in cold weather and at high altitudes. 
To asses the environmental impact of substituting petrol with ethanol, both fuels have to be compared 
regarding their emissions. Therefore a detailed comparison between emissions of ethanol and petrol 
combustion will be done. 
Harmful engine exhaust emissions from combustion of ethanol are generally lower when compared to 
the tailpipe emissions of fossil petrol. Thus ethanol can reduce certain vehicle pollutant emissions which 
exacerbate air quality problems, particularly in urban areas. 
Among the biggest benefits from using ethanol is the high reduction potential of 
carbon monoxide 
(CO) emissions. The use of E10 is reported to achieve a 25% or greater reduction in carbon monoxide 
emissions due to the increased oxygen content of ethanol (OECD/IEA 2004 p. 112). Ethanol contains 
approximately 35 % oxygen which promotes a more complete combustion of the fuel. Thus, in some 
countries, ethanol is used as oxygenate for fossil petrol and is increasingly replacing the oxygenate MTBE 
due to the high ground water contamination potential of MTBE. 
On the other hand ethanol-blended petrol emits higher evaporative hydrocarbons (HC) and other 
volatile organic compounds 
(VOCs) than petrol. When ethanol is added to gasoline, evaporative VOCs can 
increase due to the higher vapor pressure, measured as Reid Vapor Pressure (RVP) of the ethanol mixture. 
Generally, adding the first few per cent of ethanol triggers the biggest increase in volatility. Raising the 
ethanol concentration further does not lead to significant further increases (and in fact leads to slight 
decreases), so that blends of 2%, 5%, 10% and more have a similar impact. 
Impacts of ethanol on 


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