What causes air pollution?
Air pollution comes from many sources including burning of fuels for home heating, vehicle exhausts, industrial processes, volcanoes, wind-blown dust, and pollen. There are many pollutants emitted from these sources including particles and gases. The pollutant of most concern in many New Zealand towns and cities are particles small enough to be inhaled, referred to as PM10.
The level (or concentration) of pollutants in the air at any given time depends on the quantity of pollutants being released into the air (known as emissions), and how these emissions are affected by the weather. They can be dispersed by winds or removed by rain. On cold, still days, air pollutants can build up and this is often reflected in the data collected by regional councils and unitary authorities.
In many New Zealand towns, particularly in the South Island during winter time, a temperature inversion can form on clear nights, creating a layer of warm air that traps cooler air and any air pollutants underneath. Temperature inversion most often occur in towns situated in valleys or basins, where night time temperatures are low, and there is no wind. The combination of temperature inversions and higher levels of air pollutants being emitted in winter from households burning wood and coal, leads to poor air quality in these towns.
What is measured?
Regional councils and unitary authorities that conduct air quality monitoring usually measure PM10. Other pollutants are also measured by some councils and reported on LAWA where available. This includes PM2.5, carbon monoxide, nitrogen dioxide, sulphur dioxide, ozone and benzene.
Who is responsible for measuring air quality?
Regional councils and unitary authorities measure outdoor air quality in their regions as part of their responsibilities for managing air quality. National Environmental Standards for Air Quality (NES-AQ) are regulations made under the RMA that set limits in outdoor air for PM10, carbon monoxide, nitrogen dioxide, sulphur dioxide and ozone to provide a minimum level of health protection for all New Zealanders.
Regional councils and unitary authorities report on how levels of air pollutants in their towns compare to the NES-AQ and to other national and international guidelines. In many places PM10 levels fail to meet the air quality standard largely due to the combination of settled weather and higher emissions from home heating during winter. Monitoring air quality helps councils evaluate the effectiveness of strategies and interventions designed to improve air quality.
What is PM10?
These are tiny particles, smaller than 10 microns across, which is about one-fifth the diameter of a human hair. The smallest of these particles can be inhaled deep into the lungs, irritating the breathing passages.
What are the health risks of PM10?
On average, a person inhales about 14,000 litres of air every day, and the presence of pollutants in this air can adversely affect people’s health. PM10 is associated with many health problems such as irritation of the eyes and nose and making existing respiratory or cardiac problems worse. In 2012 there were around 1,000 premature deaths in New Zealand associated with exposure to airborne particles. People with pre-existing respiratory and heart conditions, young and elderly are particularly vulnerable.
What can people do to improve air quality where they are?
- Use clean heating:To improve air quality use clean home heating appliances. Older woodburners pollute the environment so heatpumps, pellet burners, or low emission burners are better alternatives. Residents can check with their local regional council or unitary authority for guidelines and information on this, and many offer schemes to help with the transition to cleaner technology.
- Be savvy fire starters: It’s important that if burning wood, the wood is dry, seasoned and non-treated. People should buy firewood from trusted suppliers and become savvy fire starters by following better burning advice: www.warmercheaper.co.nz/
- Reduce outdoor burning: Refrain from burning waste and vegetation outdoors (especially plastic, treated timber, wet vegetation, and toxic material), as it contributes to air pollution. Alternatives such as composting, mulching, using kerb-side collection services, or visiting a transfer station are recommended. Some areas have strict outdoor burning rules in place over winter months to protect air quality, so people should check their local regional council or unitary authority regulations. And, remember to always ‘check it’s alright before you light’ with the fire department: www.checkitsalright.nz/
- Be a helpful neighbour: If people see excessive air pollution that doesn’t look quite right, they can contact their local regional council or unitary authority to report it. Many councils have processes for providing advice to the responsible party, and in serious cases may enforce regulations. This is important for ensuring everyone can enjoy clean air.
- Reduce transport emissions:Instead of the car, people can walk, cycle or take public transport whenever possible. This is not always possible, so for those who drive, they can service their car regularly to reduce exhaust fumes. Electric cars don’t contribute the same emissions as petrol or diesel powered vehicles, so if people are in the position to make the switch this is a great option.
- Contribute to air quality policies and plans:People can get involved with central and local government air policies and plans. A person’s local regional council or unitary authority is a good place to start, as they welcome feedback from their communities.
What is Land, Air, Water Aotearoa (LAWA)?
LAWA aims to connect New Zealanders with their environment through sharing scientific data online. It is world-leading in its open approach to making data collected by authorities, freely available to the public. This is made possible by a collaboration of New Zealand’s 16 regional councils and unitary authorities, Ministry for the Environment, and Cawthron Institute. It has worked with and received support from many New Zealand organisations including Massey University and the Tindall Foundation.LAWA is committed to sharing the best available information, so New Zealanders can make informed decisions.