A study conducted by researchers at the Stockholm University claims that automobile tires maybe an unexplored and potential source of carcinogenic dibenzopyrenes. These are a type of polycyclic aromatic hydrocarbon (PAH), which are potent atmospheric pollutants and therefore harmful for the environment. Let us explore after the break about the findings of the study.
The main hazardous substance that the study talks about is HA oils or highly aromatic oils that are used as softeners during the tire manufacturing process. These contain concentrations of about 10 to 30 percent PAHs. PAHs are organic compounds produced due to incomplete combustion and can be classified as carcinogenic environmental toxins that cause harmful and long lasting impact on both humans as well as aquatic life.
To bring the situation under control directives have been passed that forbid the use of these HA oils anywhere more than one milligram. One such directive is regulated by EU Directive 2005/69/EC. This is expected to reduce PAH emissions that originate from tire tread wear by approximately 98 percent. Even stock piles scrap tires are a source of PAH emissions, which makes even their recycling a hazardous for the environment.
At Stockhold University, researchers used pressurized fluid extraction for analyzing 8 different types of tires for 15 high molecular weight (HMW) polycyclic aromatic hydrocarbons (PAH). They discovered that 92.3 percent PAH content was attributed to five varieties, which includes, benzo[ghi]perylene, coronene, indeno[1,2,3-cd]pyrene, benzo[e]pyrene and benzo[a]pyrene.
The study also threw light on the fact that the total mean of the main dibenzopyrenes found in tires was lower when compared with diesel and gasoline exhausts. One important thing that needs to be remembered here is that the size of the emission particles differently affects the environment and human health. For the study all tires that were studies were manufactured before 2010 when the directives had started to be implemented across sectors , therefore, more research will be required for analyzing the exact impact the PAH emissions have in the real times.