Guest Contributor: David Conway Environmental Scientist
Over the past three years, REBUILD globally has taken approximately 4,000 tires, and turned them into sandals. REBUILD globally reuses tires, which prevents “end of life” tires and scrap tires from becoming part of a tire pile, or worse, a tire fire. Rather, the scrap tires become footwear!
In the hierarchy of the three R’s, “Reduce, Reuse, Recycle”, the reuse of existing materials is second to “reduce” in preventing harmful greenhouse gases from being released into the Earth’s atmosphere. However, in terms of scrap tires, the reuse of materials is most effective in preventing GHG emissions, as the “reduce” step must occur at the source of the waste, the tire manufacturers. Lately, reusing has been referred to as “upcycling”.
Though recycling scrap tires is an excellent alternative, infrastructure to do so must be in place. Even when this is the case, the processes to retread tires, recycle tires into building materials, or recycle tires into a fuel source are energy consuming, and may carry a large carbon footprint as a result. As such, by using a low energy process to extract useable material for footwear from scrap tires, REBUILD globally prevents tires from being sent for uses with a higher carbon footprint.
Due to the composition of the tires, only the sidewalls are reusable for footwear. Six pairs of sandals are created from each tire. Remaining materials have been utilized for tire gardens, retaining walls to help prevent erosion, and various other projects.
By collecting scrap tires from the streets of Port-au-Prince for reuse, REBUILD globally helps to reduce the risk of open tire fires, improve the environment, and reduce greenhouse gas emissions. Read on below for more information on the positive impacts to Port-au-Prince from tire upcycling!
Open tire fire emissions are extremely toxic. Emissions include, among many others, Carbon monoxide (CO), volatile organic compounds (VOCs), polynuclear aromatic hydrocarbons (PAHs), benzene, polychlorinated biphenyls (PCBs), as well as metals such as arsenic, mercury and zinc (EPA, viii). Of the previously mentioned, VOCs, PAHs, benzene, PCBs, and arsenic are known carcinogens. Significant short-term and chronic health hazards, depending on the length of exposure, can result (EPA, viii). In a study conducted in 1992, the mutagenic emission factor of open tire burning was found to be three to four times greater than that of the burning of oil or coal for fuel (Lemieux and DeMarini).
Scrap Tires and the Environment
In addition to air emissions, burning tires can also result in the generation of dangerous chemicals, which can negatively impact soil, surface water and groundwater (EPA, viii). Further, when open tire fires are around, people try to put them out, or at least spray water on them to keep the heat down. This water then runs off into streams, waterways, and surrounding ground areas. The previously mentioned chemicals and carcinogens are carried by the water, polluting the surrounding environment.
Tires dumped in freshwater environments can also have a negative impact. Environments vary greatly, as do makes of tires, so there is some difficulty in determining this. However, based on laboratory research and generally speaking, tire leachate is likely toxic to some fish species and invertebrates, as well as microorganisms. Levels of organic compounds and metals in water, such as aluminum, mercury, manganese, lead, and zinc may be elevated. Additionally, levels of leachate compounds from submerged tires likely increase over time (New Zealand Ministry for the Environment).
Mosquitoes love tires! Tires hold water, keeping it warm. Scrap tires are usually found in large piles, providing perfect breeding grounds for mosquitoes. As such, the presence of discarded scrap tires can actually increase the risk of mosquito-borne illness, thus causing a public health issue.
Greenhouse Gas Emissions Reduction
Port-au-Prince lacks the infrastructure for recycling tires. However, we don’t think that this necessarily a bad thing! By reusing the tires, rather than recycling them through energy consuming processes, REBUILD globally reduces greenhouse gas emissions in the tire life cycle, and thus, the carbon footprint of a typical “end of life” tire.
Carbon footprint is expressed in metric tons of carbon dioxide equivalent (MtCO2e), which converts quantified greenhouse gases into a single measurement. Some of the greenhouse gases in this measurement include Carbon Dioxide, Methane, and Nitrous Oxide.
The average tire weighs approximately 20 pounds. At 4,000 tires, REBUILD globally has reused approximately 80,000 pounds of scrap tires, equivalent to approximately 36.3 metric tons. According to a carbon footprint calculation conducted by the Institute for Environmental Research and Education (IERE), average carbon emissions for recycling scrap tires is approximately 124 kg CO2 equivalents per ton sold in the United States (IERE, 2). Using this number, the following calculation from the EPA’s Pollution Prevention Program’s Greenhouse Gas Calculator was executed:
36.3 t x 124 kg CO2e/t x (1 MTCO2e / 1,000 kg CO2e) = 4.5 MTCO2e
As can be seen above, over the past three years, by upcycling scrap tires, REBUILD globally has reduced greenhouse gas emissions by 4.5 metric tons of carbon dioxide equivalent. This does not take into account GHG emissions from production, transportation, etc.
Additionally, according to a study conducted by the Centre for Remanufacturing and Reuse (CCR), the carbon footprint of retreading a scrap tire is approximately 60.7 kg CO2 (CCR, 2). Based on this information, each sandal produced prevents approximately 5 kg CO2 from being emitted to Earth’s atmosphere (each pair = 10 kg CO2).
Reducing the carbon footprint of tires one sandal at a time!