Medical Mythbusting Commentary for October 14, 2025

Source:
Climate pollution from inhalers has the impact of half a million cars per year, study finds

Reference:
Inhaler-Related Greenhouse Gas Emissions in the US; A Serial Cross-Sectional Analysis

Question:

The study showed that In one year alone, planet-warming pollution from inhalers were the equivalent of driving more than half a million cars, or the same as electricity requirements for 470,000 homes. If there are about 1.6 billion combuction engine vehicles that account for 6-7% of all emissions worldwide, what is the percentage contribution of inhalers to the total global output from all sources?

Answer:

The study you referenced is U.S.-specific, estimating annual emissions equivalent to more than 500,000 cars (or electricity use for 470,000 homes), based on about 2.3 million metric tons of CO₂e from U.S. inhalers in 2024. Globally, inhaler emissions scale up to roughly 13–16 million metric tons of CO₂e per year (extrapolated from U.S. data and prevalence of asthma/COPD, which affects ~600 million people worldwide).

• Total global GHG emissions: ~51.8 Gt CO₂e in 2023 (including all sources like energy, industry, agriculture, and waste).
• Inhaler share: (15 million tons / 51,800 million tons) × 100 ≈ 0.03%.

Using your vehicle data for cross-check:

• The 1.6 billion combustion-engine vehicles emit ~6–7% of global totals (~3.1–3.6 Gt CO₂e annually).
• An average vehicle emits ~4.6 metric tons CO₂e/year.
• U.S. inhalers = ~500,000 vehicles’ worth (2.3 million tons).
• Scaling to global (U.S. vehicles ~18% of world total): Global inhalers ≈ 2.8 million vehicles’ worth (~12.8 million tons).
• Share of vehicle emissions: ~0.175% (2.8M / 1.6B).
• Share of global emissions: 0.175% × 6.5% (midpoint) ≈ 0.011% (conservative; broader estimates hit 0.03% including non-U.S. MDI use).