Air Basics
Which gas makes up most of the air we breathe?
N (Nitrogen)
Name one major vehicle on the road that releases NO₂ exhaust into the air.
A car, bus, or truck.
What is the full name of NO₂?
Nitrogen Dioxide
What colour appears when the test chemicals react with the collected nitrite?
What if a school replaced some car journeys with walking or cycling? How might this affect local air quality?
It could reduce vehicle emissions and potentially lower local NO₂ levels.
True or False: Clean-looking air is always pollution-free.
False
Is a busy traffic intersection likely to have higher or lower NO₂ pollution than a quiet forest path?
Higher NO₂ pollution
What does the number "2" in the formula NO₂ stand for?
It means there are two oxygen atoms for every one nitrogen atom.
If a tube shows a very dark color change after lab analysis, does that mean there was high pollution or low pollution?
High pollution (more trapped gas means a stronger color change).
What if a diffusion tube fell off its stand halfway through the experiment? Why might this be a problem?
It might not collect NO₂ exposure for the full planned period, making the result less comparable with other tubes.
What percentage of the air is made up of oxygen?
21%
True or False: Rainy days can help wash some dust and gas pollution out of the air.
True
If you cannot see NO₂ in the air, how could scientists investigate whether it is present?
Use a diffusion tube to collect it and test the sample.
What is the scientific word for gas particles moving naturally from the outside air into our tube?
Diffusion
What if your class found higher NO₂ levels in a park than beside a busy road? Should you immediately conclude that the park is more polluted? Why or why not?
No. You should check the data and consider other factors, such as weather, nearby pollution sources, and measurement uncertainty.
True or False: Carbon dioxide (CO₂) makes up more than half of the air around us.
False. CO₂ and other rare gases make up only about 1% of the total air.
Name three things that can cause air pollution.
Cars, buses, factories, smoking, forest fires, burning fuels, etc.
Does a low NO₂ level prove that the air is 100% clean of all other pollutants?
No, because the tube only measures NO₂, not every type of pollution.
If two tubes show the exact same color change after being tested for the same amount of time, what can you conclude about the pollution level at both places?
Both locations had the same average level of NO₂ air pollution.
What if two locations had the same average NO₂ exposure over a month, but one had much busier traffic during rush hour? Could the tube results show this difference?
Not necessarily. The tubes measure exposure over time and do not show the exact NO₂ level at each moment.