From data to carbon dioxide

To be able to calculate the Second Hand Effect from our marketplaces we need climate data for the products sold on these sites. To get this data we make a life-cycle analysis of the different products. We look at what materials the products are made of, how these are produced and waste generated in production and at disposal. All data are then recalculated into their equivalents in tons of carbon dioxide.

Analyzing the products sold on our marketplaces demands certain specific calculations and conversions.
In order to develop emission data for material extraction, material production, and waste management, IVL developed material partitions for the various product categories on each site. In each selected product category, random sample tests on 10-50 published ads were made. These ads were analyzed and the products’ average material partition was calculated. An average product in category ”Sofas & Chairs”, for example, consists of 30 percent wood, 11 percent steel, 18 percent polypropylene, 20 percent polyurethane, 10 percent polyester, 7 percent cotton, 3 percent leather, 1 percent wool.

In all, 20 material partitions were produced; each representative to at least one of the selected product categories. That several categories fit into the same material partitions is due to the fact that a car stereo, for instance, has a similar material partitions as a home stereo system, but the products are found in various categories on each site.


For each material, climate data for raw material extraction, material production, and waste management was calculated. The total was calculated into tons of carbon dioxide equivalents (CO2e). The value per material was converted to the composition of each material partition so that each material partition received a discharge value in kilograms of CO2e per material partition. This was subsequently multiplied by the average weight per advertisement, in order to produce the tons of CO2e per ad. This emission value represents a standard for saved emissions from a product in the category that didn’t have to be produced. This value formed the basis for the calculation of the climate benefits (saved emissions) for each product category of each site.


The impact of the transportation of goods between seller and buyer was also added to the calculation – i.e. not an environmental benefit but a negative impact. An average distance of 44 km per ad was calculated, based on the Swedish marketplace Blocket’s customer survey, and the climate impact from transport by passenger car (petrol). The estimation of distance gathered in Blocket’s customer survey is used for all sites because all other marketplaces respective distances are equivalent or lower. Climate impact (not climate benefit) from the operation of data centers and offices was also added to the calculation. This was compiled by adding the climate impact from electricity production, both green electricity (wind and water) and the average national electricity mix (nuclear, hydro, coal condensate power, biofuel, etc.).


All the climate data, ad data and the impact of operations was entered into the carbon footprint calculator that IVL has developed and the potential climate benefits of the categories were calculated.