ANAESTHESIA · ENVIRONMENTAL AWARENESS
Explore the CO₂-equivalent emissions of inhaled anaesthetic agents.
An educational tool byGreen TheatreDisplayed concentrations are calculation inputs only and are not recommended clinical settings.
No patient data. Calculator entries are not stored.
6.6 mL
10 g · liquid equivalent
11.9 km
Illustrative UK car comparison
Car comparison: 0.16272 kg CO₂e/km. UK Government, 2025. Actual emissions vary by vehicle, fuel efficiency and driving conditions.
02 / EXPLORE
Same fresh gas flow and duration · kg CO₂e
The concentrations shown are calculation inputs and do not imply clinical equivalence or recommended dosing.
N₂O is calculated separately as a delivered gas and is not included in these bars. Each volatile agent uses its current input, or its default until edited.
Sevoflurane · 2% · 60 min held constant
A mathematical illustration of calculated emissions. This chart does not recommend a fresh gas flow for a patient.
03 / UNDERSTAND
Concentration, fresh gas flow and duration give the delivered gas volume. Molecular weight converts this to mass. The agent’s 100-year global warming potential (GWP100) then expresses its climate impact relative to the same mass of CO₂.
Volume (L) = concentration (%) ÷ 100 × flow (L/min) × duration (min)Mass (g) = volume (L) × molecular weight (g/mol) ÷ 24.1 (L/mol)CO₂e (kg) = mass (g) × GWP100 ÷ 1,000Liquid (mL) = mass (g) ÷ density (g/mL)Distance (km) = CO₂e (kg) ÷ 0.16272 (kg CO₂e/km)| Agent | GWP100 | Molecular weight g/mol | Liquid density* g/mL | Physical properties |
|---|---|---|---|---|
| SevofluraneHFE-347mmz1 | 195 | 200.05 | 1.520 | DailyMed label |
| DesfluraneHFE-236ea2 | 2,590 | 168.04 | 1.465 | DailyMed label |
| IsofluraneHCFE-235da2 | 539 | 184.5 | 1.496 | DailyMed label |
| Nitrous oxideNitrous oxide | 273 | 44.0128 | Not applicable | NIST WebBook |
All four GWP100 values use the IPCC Sixth Assessment Report (AR6), 2021, Working Group I, Chapter 7 Supplementary Material, Table 7.SM.7 in section 7.SM.6 (greenhouse-gas lifetimes, radiative efficiencies and metrics). Values describe a 100-year time horizon, relative to CO₂ = 1.
The GWP100 assigned to sevoflurane remains an area of discussion in recent scientific literature. This calculator uses the IPCC AR6 value consistently with the other agents so that values are derived from a single GWP source.
Molar volume: 24.1 L/mol. A fixed ideal-gas approximation at approximately 20°C and 1 atmosphere, using Vₘ = RT/P. It is a modelling assumption, not a measured volume for every theatre condition. NIST molar gas constant.
*Densities are approximate g/mL values based on the product labels’ specific gravities: sevoflurane 1.520 (lower end of 1.520–1.525 at 20°C); desflurane 1.465 (20°C/4°C); isoflurane 1.496 (25°C/25°C). For this estimate, the water reference density is approximated as 1 g/mL. N₂O is calculated as a gas, with no liquid conversion.
0.16272 kg CO₂e per vehicle-kilometre. UK Government GHG Conversion Factors 2025, average petrol car, passenger vehicles. This is a UK fleet-average operational factor, excluding fuel production and vehicle manufacture; it is not an India-specific factor. Real vehicle emissions vary considerably by vehicle, fuel efficiency and driving conditions.
This calculator assumes that all anaesthetic agent delivered is ultimately released to the atmosphere. Actual emissions may differ where capture, destruction or other waste-gas management systems are used.
This is a simplifying, conservative assumption for delivered agent. Concentration and flow are treated as constant for the entered duration. Patient uptake, metabolism, circuit behaviour, supply-chain leakage, manufacture, transport and equipment energy are not modelled. This is not a full life-cycle assessment.