The importance of good air quality and how poor air quality can affect us.
What pollutes our air
Air pollution is caused by human activities such as:
- burning of fuels for home heating
- industrial processes
- vehicle exhausts (particularly diesel)
- road dust
It is also caused by natural sources (eg, wind-blown dust, pollen, sea salt and volcanic eruptions).
When the air we breathe is of poor quality it can affect our health
On average, a person inhales around 14,000 litres of air every day. When the air we breathe is of poor quality it can affect our health.
Particulate matter (PM) is a collective term for solid and liquid particles suspended in the air and small enough to be inhaled. PM varies greatly in structure and chemical composition depending on where it comes from. PM comes from human activities and natural sources. It is often classified according to its size because size determines how PM interacts with the environment and human body.
- PM10 has a diameter of 10 micrometers (µm) or less
- PM2.5 has a diameter of 2.5 µm or less and is a subset of the PM10 range.
The diagram below compares the size of PM10 and PM2.5 particulates to a strand of hair and a grain of beach sand. These airborne particles are tiny – too small for the human eye to see. They can cause adverse health impacts ranging from irritation of the nasal tracts to respiratory and cardiac disease and even premature death.
The relative size of particulate matter
Source: Ministry for the Environment
The diagram compares the size of PM10 and PM2.5 particles to a strand of hair and a type of beach sand. They are tiny – too small for the human eye to see.
Impacts of poor air quality
Air quality in New Zealand is relatively good by international standards, however there are areas of the country where air quality needs to improve.
When poor air quality affects our health it also affects our economy due to increasing medical costs and lost productivity when people are unable to work.
Some air pollutants settle on land and waterways or wash into them, which can affect these environments.