Table 3 The source of information for items used in the carbon footprint calculator.
From: Carbon footprint of private dental laboratories in Egypt: A cross-sectional study
Item | Source of information |
|---|---|
Number of workdays per year | The laboratory manager was asked about the average number of days the laboratory was open per week and the number of days the laboratory was closed during national holidays. |
Number of full-time staff | The number of full- and part-time technicians, receptionists, accountants, administrative personnels, cleaning and sterilization personnel, human resources personnel, and couriers were collected. Because the calculator uses the number of full-time staff for the calculation of staff travel per year, each two part-time staff were considered one full-time staff. |
Number of prostheses/appliances that the laboratory makes per year (Indirect restorations and appliances, including crowns, bridges, veneers, removable dentures, surgical guides, and orthodontic and pedodontics appliances) | The laboratories did not keep record of the fabricated prostheses/appliances, so the laboratory manager was asked to record the number of prostheses/appliances fabricated in a week. This was averaged and multiplied by the average number of workdays in a year. |
Staff travel to or for the laboratory by any of the following methods (petrol/diesel car, electric car, bus, train, motorbike, bike/walk) in miles | The staff were asked about their residence locations. The shortest distance from their residence to the laboratory, as calculated by the Global Positioning System (GPS), was used to determine staff travel distance for each transportation method and was multiplied by two to calculate the total distance per return journey. The distance that the part-time staff traveled was calculated and allocated according to the number of workdays. The total distance traveled by the staff was then summed for each transportation mode. The Tuk-Tuk (auto-rickshaw) is a three-wheeled transportation vehicle that is popular in less urbanized areas. It has the same engine design as the motorbike and emits equal carbon amounts [50]. The distance traveled by the Tuk-Tuk was calculated among the distance traveled by the motorbike. The tram and metro (underground) are popular electricity-powered mass transportation methods in Alexandria and Cairo, respectively. They emit more carbon per passenger-kilometer than electric cars, equivalent to a diesel train [44]. The distances traveled by the tram and metro were included in the calculations for train travel. Each laboratory hired several couriers, who traveled by motorbikes, to deliver the prostheses/appliances and dental impressions to and from the clinics. The laboratory manager was asked about the location of the clinics they deliver their services to by couriers and the frequency that the couriers made these rides per day. The average distance between the clinics and the laboratory was calculated and multiplied by the average number of rides per day to obtain the average distance traveled by each courier. |
Number of waste bags that the laboratory discards per week*: Plastic waste for recycling, cardboard waste for recycling, infectious waste** for incineration and domestic waste for disposal (each bag weighing 6.72 kg) | The cleaning personnel were asked to count and weigh the waste bags discarded during an average week. This number was multiplied by the average weight of the bag and then divided by 6.72 kg [2]. |
Consumption of standard electricity, green electricity, solar power on the laboratory’s roof, and gas last year in kilowatt hour (kWh) | Energy consumption in last year’s bills was summed. If any monthly bill was missing, the average consumption was used as a substitute for that month. There were no gas bills because the laboratories used gas tanks instead of pipelines. The laboratory manager was asked about the average number of gas tanks used per month. This was multiplied by the average capacity of gas tanks in Egypt (7.93 gallons) and multiplied by a gasoline gas equivalent (36.6) to obtain the number of kWh consumed per month [51]. |
Water consumption last year in cubic meters (m3) | Water consumption in last year’s bills was summed. If any monthly bill was missing, the average consumption was used as a substitute for that month. |
Expenditure on equipment and materials during the last year GBP (not including rent or interest) | Last year’s invoices for dental materials, equipment, and administrative costs were summed. The depreciation cost of equipment (porcelain, burnout and sintering furnaces, sandblasters, compressors, Computer-aided Design/ Computer-aided manufacturing (CAD/CAM) milling machines, computers, trimmers, Bunsen burners, extra-oral scanners, handpieces, micromotors, 3-D printer, trimmers, flasks, and washing and polishing machines, and induction casting machines) was calculated and added to the cost of procurement in a separate calculation. Procurement costs were converted to GBP by dividing the laboratories’ expenses by the average Egyptian Pound value during 2023-2024. |
