Ammonium sulphate: Emissions
A fertiliser that recycles industrial waste
What this tab covers The greenhouse-gas footprint per tonne, split by lifecycle phase (feedstock, production, movement, use, end of life), the global total, other environmental impacts, levers and low-carbon routes, India's position, and where the investment opportunity lies. Emission intensity 0.50 t CO2e per t range 0.1-0.9 · synthetic AS about 0.65-0.7 (0.258 t ammonia at about 2.4 t CO2/t plus drying); by-product AS lower under economic allocation; indicative average Global emissions per year 16.0 Mt CO2e per year 2024 · 0.5 t x 32.9 MtPer t of ammonium sulphate, cradle-to-gate. Intensity: derived from IEA Ammonia Technology Roadmap 2021 (indicative). Global total: derived (indicative).
Share of footprint by lifecycle phase
Feedstock 76% Production / process 14% Movement 10%Footprint by lifecycle phase
| Phase | Intensity | Share | Main sources of emissions | Notes | Source |
|---|---|---|---|---|---|
| Feedstock | about 0.38 t CO2e/t (allocated ammonia and acid) | 76% | ammonia footprint; allocation choice for by-product routes | mass allocation would assign much more of caprolactam's footprint | derived (indicative) |
| Production / process | about 0.07 t CO2e/t | 14% | evaporation and crystallisation steam, drying | neutralisation heat partly offsets | indicative |
| Movement | about 0.05 t CO2/t | 10% | long-haul bulk shipping from China to Brazil and Europe | low N content makes transport emissions per unit N relatively high | IMO Fourth GHG Study 2020 (indicative) |
| Use | about 0.9 t CO2e per t from field N2O at the IPCC 1% default (derived: 0.21 t N x 1% x 44/28 x 273), plus CO2 from lime used to correct acidity | – | nitrification of ammonium; soil acidification | ammonium sulphate is the most acidifying common N fertiliser (indicative) | IPCC 2019 Refinement (indicative) |
| End of life | not applicable | – | consumed in soil | nitrate leaching and sulphate runoff | indicative |
Other environmental impacts
Soil acidification requires liming; by-product AS can contain trace contaminants; it recycles waste ammonia and sulphur from industry, a circular benefit.
Levers to cut emissions
- Use more by-product AS instead of synthetic N where sulphur is needed
- Low-carbon ammonia for synthetic AS
- Ammonia-based FGD that turns SO2 into fertiliser
- Better placement and inhibitors to cut field N2O
India
India's AS footprint is small; most is imported Chinese by-product. India's fertiliser emissions are dominated by urea (see nitrogen and urea tiles).
Emission figures are indicative global averages from the life-cycle studies named; actual footprints vary widely by site, energy mix and method.Low-carbon routes
| Route | Intensity | Cost premium | Status | Source |
|---|---|---|---|---|
| AS from green ammonia and by-product acid | about 0.1-0.2 t CO2e/t (indicative) | about $65-180/t AS at green ammonia premiums of $250-700/t (indicative, derived) | Daures project in Namibia (development stage, up to $3.6 million funding, CRU 2026) | CRU BCInsight (2026); derived |
| AS from ammonia scrubbing of flue gas and biogas digestate (ammonia stripping) | low; recovers waste nitrogen | small to moderate (indicative) | commercial in Chinese FGD and European biogas plants (indicative) | indicative |