What pollutes the air?
In the simulator, you replace four sources with clean solutions.
| Source | Main pollutant | Solution |
|---|---|---|
| Raw coal | soot, SO2 | Improved fuel |
| Old bus | black diesel smoke, nitrogen oxides | Electric bus |
| Smoke from home stoves | smoke from low chimneys | Central heating |
| Open burning of trash | toxic smoke such as dioxins | Trash collection |
In Ulaanbaatar, the main source of winter smog is the stoves in the ger (yurt) districts. Smoke from low chimneys spreads at the height where people breathe.
Why do soot and PM2.5 form?
With enough oxygen, coal burns completely: C + O2 → CO2. Without enough oxygen, it burns incompletely and forms carbon monoxide and soot: 2C + O2 → 2CO. Compressed fuel briquettes burn completely at high temperature, so they give off few particles.
PM2.5 means particles with a diameter of 2.5 micrometers or less. A human hair has a diameter of about 70 micrometers, which is about 30 times larger. Particles this small go deep into the lungs.
How do you read AQI?
The higher the number, the more polluted the air. The categories below come from the U.S. AirNow website.
| AQI | Category |
|---|---|
| 0–50 | Good |
| 51–100 | Moderate |
| 101–150 | Unhealthy for sensitive groups |
| 151–200 | Unhealthy |
| 201–300 | Very unhealthy |
| 301 and higher | Hazardous |
Clean up the city air in the Nalukh chem app
Stop each source, replace it with a clean solution, and bring the AQI down. This simulator is included with full access. The app is free to download, and 2 units and 5 simulators are open with no sign-up.
How do you use the simulator?
- Tap a polluter in one of the four cells in the bottom row to stop it. The cell empties and shows which solution it needs.
- Grab the matching solution from the Clean solutions tray on the right and drag it to the empty cell.
- If you drag a solution to a source that is still running, or if the solution does not match, the explanation line shows the reason.
- With each step, the AQI on the Air pollution meter falls and the sky clears.
- Each source takes two steps: stop it and place the solution. After 8 steps in total, the AQI reaches 50.
The AQI steps in the simulator are not real city measurements. They are an example that shows the trend. The five-level label in the top corner also differs from the table above.
Tasks to try in the simulator
- Only stop the four sources. What does the AQI become? Answer: 185. Then place the solutions and bring it down to 50.
- Write down the AQI at each step and compare it with the table. At which steps does it fall below 200 and below 100? Answer: at steps 4 and 7.
- Drag a solution to a source that you have not stopped, and read the hint.
- Think about why it is not enough to only stop the stoves and buses. How will families get heat, and how will people travel?
