
About
a-minute read:
The
air 空气 kōng qì around
us is made up of a mixture of gases.
| Gas |
Percentage
(%)
|
| Nitrogen | 78 |
| Oxygen | 21 |
| Carbon dioxide | 0.03 |
| Inert gases | < 0.5 |
| Water vapour | variable |
| Dust | variable |
| Microorganisms | variable |
Air 空气
kōng qì is
a mixture because the components (such as nitrogen, oxygen and carbon
dioxide) are physically mixed
and the composition is not fixed. For example, inhaled air has
0.03% carbon
dioxide and
21% oxygen.
Exhaled air has about 4% carbon
dioxide and
17% oxygen.
This shows that the composition of air changes with time and
place.
Read also
atmosphere 大气层 dà qì céng