Which UN number refers to aerosols in Divisions 2.1 and 2.2?

• A. UN 3478 and UN 3479, fuel cell cartridges
• B. UN 1950, aerosols, in Divisions 2.1 and 2.2
• C. UN 1951, aerosols unrelated
• D. UN 2037, gas cartridges and receptacles, in Divisions 2.1 and 2.2

Answer: (B)

Aerosols carried under transport rules are identified by UN 1950. The key idea is that the UN number serves as the single identifier for the substance, while the division (2.1 or 2.2) describes the type of gas under pressure inside the aerosol. So, regardless of whether the aerosol falls under Division 2.1 (flammable gas) or Division 2.2 (non‑flammable gas), the correct UN designation remains 1950. The other numbers point to different items (fuel cell cartridges, gas cartridges, or a different aerosol entry), so they don’t apply here.