What it is
A really useful scale that tells us what the quality of our air is.
Where it comes from
The EPA calculates AQI based on 5 major pollutants:
ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide.
What it is & Where it comes from
PM stands for particulate matter (also called particle pollution): the term for a mixture of solid particles and liquid droplets found in the air.
Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.
Why it's bad for us
The size of particles is also important for health impacts. Generally, the larger sized particles (between 2.5 µm and 10 µm) when breathed in remain in the upper airways. Whereas smaller particles (PM2.5 and smaller) can lodge deeply in the lungs and even enter the bloodstream. PM2.5 particles are typically produced by human activities, such as burning of wood and fossil fuels.
Source: Land Air Water Aotearoa, US EPA
What it is & Where it comes from
A reddish-brown, pungent gas that is formed when nitric oxide emissions (e.g., from traffic exhaust) react with other chemicals in the air.
Why it's bad for us
NO2 can cause respiratory infections, respiratory disease, and reduced lung development in young people.
Sources: Land Air Water Aotearoa, US EPA