High air pollution events
We monitor PM10 and PM2.5 concentrations in eight airsheds in Waitaha/Canterbury. We issue advisories when these particles reach elevated concentrations.
Current PM10 and PM2.5 events
These figures represent the number of high pollution events this calendar year.
High pollution events are a 24-hour periods when the average concentrations exceed national standards and guidelines in each airshed.
The National Environmental Standards for Air Quality (NESAQ) target for PM10 is one or fewer events in 12 months. The Canterbury Air Regional Plan (CARP) target for PM2.5 is no events by 2030.
What are PM10 and PM2.5
The air quality standard we exceed most often relates to airborne particles, also known as particulate matter (PM). These tiny particles are less than 10 micrometres in diameter (about a fifth of the thickness of human hair).
These include fine particles (less than 2.5 micrometres), known as PM2.5, and coarse particles (between 2.5 and 10 micrometres), collectively referred to as PM10. Together fine and coarse particles are known as PM10.
These particles are important to monitor because they are small enough to be inhaled and can cause health problems.
Visit the LAWA website for more information on air pollutants - particulate matter.
Relative size of particular matter (PM) - Lawa | Land Air Water
Sources of particulate matter
Fine particles come from combustion sources like home heating, industry and vehicles. Dust and sea salt are examples of coarse particles.
In most airsheds, PM10 concentrations are usually highest on winter evenings and mostly consist of fine particles. An exception to this is Washdyke in South Canterbury, which has different sources of air pollution from other places in Waitaha/Canterbury.
In Washdyke, PM10 concentrations are high any time of the year and often highest during working hours. This suggests work-related sources that generate dust, and sea salt are more important sources of PM10 than smoke from home heating.
Health risks
There is a substantial body of evidence that breathing particulate matter is harmful to human health. PM10 and finer particles such as PM2.5 can get deep into our lungs and cause health issues, particularly for vulnerable members of society like children, older people and those with respiratory illnesses.
There are a few things you can do to ensure better, cleaner burning:
- find authorised wood burners and pellet fires for use in your area
- use one of our trusted suppliers for your next load of firewood
- read how our home heating measures relate to Clean Air Zones
- contact us if you notice an air quality incident.