Moderate
Eat less red meat
Food is ~26% of global emissions, and beef is the single most carbon-intensive food. Shifting to a plant-rich diet can cut your food footprint by up to ~50%.
Air · deep dive
The air billions of us breathe
The WHO says annual fine-particulate (PM2.5) pollution above 5 µg/m³ is unsafe. In the worst-hit countries people breathe air more than fifteen times dirtier than that — every day, with measurable cost to every organ in the body.
Bottom line: Average PM2.5 exposure is 31.3 µg/m³ as of 2020, down 21% from 39.7 µg/m³ in 1990. Tracked here with 1 related indicator: Ozone-depleting substances.
Average PM2.5 exposure
The average person breathes air about six times dirtier than the WHO safe limit — though it has begun to fall.
31.3µg/m³
latest · 2020
Dashed: projected to 35.5 µg/m³ by 2025 if the recent trend holds (not a forecast).
1990
39.7 µg/m³
change since
-21%
Ozone-depleting substances
The Montreal Protocol worked: the chemicals destroying the ozone layer are down ~99% since 1986.
1.3% of 1986
latest · 2021
Dashed: projected to -0.2 % of 1986 by 2026 if the recent trend holds (not a forecast).
1986
100.0 % of 1986
change since
-99%
Annual average PM2.5 by country (2023). Bars in red exceed 35 µg/m³ — seven times the WHO limit.
How we know · methodology
These are population-weighted annual mean PM2.5 concentrations by country from the IQAir 2023 World Air Quality Report, aggregated from ground monitors and validated low-cost sensors. PM2.5 — particles under 2.5 microns — lodges deep in the lungs and crosses into the bloodstream.
The reference line is the WHO 2021 air-quality guideline of 5 µg/m³ annual mean; bars above 35 µg/m³ (seven times the guideline) are drawn in alarm red. This is a single recent snapshot, not a time series, and is currently seed-only.
Most PM2.5 comes from combustion — transport, coal and biomass burning — so the same shift away from burning fossil fuels that cools the climate also clears the air.
Average PM2.5 exposure (IHME Global Burden of Disease 2021, via OWID) is the population-weighted global mean concentration each person breathes, the long-run companion to the country snapshot above. It climbed to a peak around 2013, then fell as China and others cleaned up — but at ~31 µg/m³ it is still roughly six times the WHO safe limit of 5. Atmospheric aerosol loading is the ninth planetary boundary, and this is the clearest global measure of it for human health.
One atmospheric problem we did fix: ozone-depleting substances. The index here (UNEP Ozone Secretariat, via OWID) tracks global consumption of controlled substances — CFCs and the like — relative to their 1986 level. After the 1987 Montreal Protocol, consumption fell by about 99%, and the stratospheric ozone layer is now slowly healing. It is the clearest proof that a co-ordinated global response to an atmospheric threat can work.
What bends this curve
Despair changes nothing; choices do. These habits measurably move the trend above — start with one, and ask the Earth guide how far it goes.
Committed
Fly less, and offset what you must
One round-trip transatlantic flight emits ~1.6 t CO₂ per passenger — about a year of a low-carbon lifestyle. Swapping one flight for rail or a call is one of the biggest single cuts you can make.
Easy
Switch to a green electricity tariff
Electricity and heat are the largest emitting sector. Moving your home to certified renewables can cut household power emissions to near zero overnight.
Easy
Waste less food
Roughly a third of all food is wasted; if it were a country it would be the 3rd-largest emitter. Planning meals and using leftovers cuts both your bin and your footprint.
Committed
Drive electric — or don’t drive
Transport is ~16% of emissions. Walking, cycling or an EV for short trips cuts both CO₂ and the PM2.5 that pollutes the air we breathe.
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