What Is GHG? Glossary of Basic GHG Inventory Terms [2026]

EcoCheck Team

06 tháng 10, 2026

KNK is the Vietnamese abbreviation for greenhouse gases (GHG) — gases in the atmosphere that trap heat and cause the greenhouse effect, including CO₂, CH₄, N₂O and industrial gases such as HFCs, PFCs, SF6 and NF3. In Vietnamese legal documents and corporate reports, "kiểm kê KNK" means a greenhouse gas (GHG) inventory under Decree 06/2022/ND-CP. This article explains GHG and the basic inventory terms you will come across.

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What is KNK (GHG)?

KNK (khí nhà kính, in English: greenhouse gas — GHG) refers to the group of gases that absorb and retain thermal radiation from the Earth's surface, warming the atmosphere. Under the Law on Environmental Protection 2020, the regulated GHGs are CO₂, CH₄, N₂O, HFCs, PFCs, SF6 and NF3. Each gas has a different heat-trapping capacity, compared using its GWP factor — see the full table in the 7 greenhouse gases.

Smoke from an industrial plant

Smoke from an industrial plant

Glossary of basic GHG inventory terms

Term	Meaning
KNK / GHG	Greenhouse gas — the subject of the inventory
CO₂tđ (CO₂e)	CO₂ equivalent — the common conversion unit for all GHGs
GWP	Global Warming Potential — the factor that converts a gas into CO₂e (e.g. CH₄ ≈ 28)
GHG inventory	Collecting data and calculating a facility's GHG emissions/removals over one year
Scope 1 / 2 / 3	Emission scopes: direct / from purchased energy / value chain
Emission factor (EF)	The amount of GHG generated per unit of activity (e.g. kg CO₂/kWh of electricity)
MRV	Measurement – Reporting – Verification: the mandatory cycle for data to be recognised
Emission allowances	The emission cap allocated to a facility; exceeding the cap means buying more
Carbon credits	Certificates for reducing/removing 1 tonne of CO₂e, which can be traded

Glossary of 9 basic GHG inventory terms: GHG, CO₂e, GWP, GHG inventory, Scope 1/2/3, emission factor, MRV, emission allowances, carbon credits

Figure 1: Glossary of 9 basic GHG inventory terms: GHG, CO₂e, GWP, GHG inventory, Scope 1/2/3, emission factor, MRV, emission allowances, carbon credits

Why should businesses care about GHG?

Because the GHG inventory is already a legal obligation: facilities emitting 3,000 tCO₂e/year or more, or consuming 1,000 TOE/year of energy or more, are on the list required to conduct an inventory and submit reports every 2 years; the thermal power, steel and cement groups began receiving emission allowance allocations from 2025–2026. All the milestones are in the GHG inventory roadmap [2026 update], and the core concepts in what are emissions? Scope 1, 2, 3.

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