Air quality

What is air and why do we need clean air?

We all need air to survive. It is a shared resource, recycled over and over since the beginning of time. Northland's air is generally of a high quality, but there is air pollution created by human as well as natural activities.

Air is an invisible gas made up, mainly, of a mixture of oxygen and nitrogen, which is breathed by all living land animals and plants. We all need to breathe air to survive, and it is becoming increasingly important to keep it clean for the future, as lots of contaminants such as smoke, dust and gases are discharged into the atmosphere.

A huge plume of black smoke.A huge plume of black smoke curls up into the air on a Ruakaka property. Fires like these are not allowed.

These contaminants can cause air pollution, which is bad because it smells, causes haze, damages buildings and plants, and it can make people sick or even kill them.

Air pollution occurs when contaminants are released into the air in amounts that could be harmful to people and animals, or could damage plants.

Some air contaminants are natural - they come from dust, gases, smoke and ash from bush fires and volcanoes. Other natural air pollutants are ocean spray, pollen from flowers, mist, insect droppings and mould growth.

Some contaminants can be seen (such as smoke, ash, soot and dust) while others are invisible (gases and odours).

Smoke contains dust and harmful gases, some of which can cause sore eyes, runny noses, asthma, cancer and heart and lung problems.

Air pollution is a big problem in major cities of the world, but it has also become a problem in Northland. There are some parts of Whangarei, for example, where the fumes from cars build up on the streetside to levels above those recommended by scientists.

Pollution gets into the air in many ways. Factories and cars are major polluters, but burning rubbish at home also has an effect on air quality.

Modern rubbish contains a lot more toxic particles such as those in plastics, so burning rubbish is not such a good idea.

The Northland Regional Council discourages people from burning rubbish in their backyards because of the air pollution caused, and because the smoke and fumes are often annoying to neighbours.

Northland Regional Council's role and policies

discharge from factories.The Council has rules about discharges from factories. The Northland Regional Council is responsible for air quality in the Northland region between Kaiwaka and Cape Reinga. Northland generally has a high quality of air, and is noted for its clear skies and clear air, especially in rural areas.

The prevailing south-westerly winds tend to move air masses across the region fairly rapidly. However, fog does occur, especially during still winter days.

In general, anybody wishing to discharge any contaminants into the air from any industrial, trade or waste management facility must first obtain a discharge permit from the Northland Regional Council, unless there is a rule in a regional plan or central government legislation that allows the discharge.

Air quality issues of the region are:

  • the effects of discharges from industrial areas;
  • discharges from various existing activities which have various localised adverse effects, including nuisance and odour problems. This includes rubbish burning, odour from waste treatment and disposal facilities (such as tips, waste ponds and effluent spraying) and dust (from sandblasting, ship loading, quarries and roads);
  • agrichemical and fertiliser overuse and spray drift on to water bodies, the effcects on neighbouring properties and non-target vegetation;
  • dust from unsealed roads affecting the use of adjacent land and buildings;
  • Northland's contribution to greenhouse gases which induce climate change, mainly due to discharges of carbon dioxide from motor vehicles, industrial fossil fuel use and methane. Methane comes mainly from livestock and also from landfills, sewerage and agricultural waste treatment facilities; and 
  • the release of ozone-reducing substances. 

Air quality staff

The Northland Regional Council manages air quality from five main angles:

  • preparing plans that set out how Northland will manage air pollution;
  • issuing resource consents to those industries that can prove they will not cause pollution from their discharges;
  • complaints;
  • monitoring resource consents; and
  • state of environment monitoring.

Specialist air quality staff follow up any air quality complaints that come in to the Council. Checks are made to ensure factories and industries are keeping to the rules on discharges to air, and other monitoring keeps track of what is happening in the environment.


Environmental hotline.Air quality staff respond to complaints about air quality that are received at the Northland Regional Council. Most of these come through the Council's special Environmental Hotline.

Most complaints are received about spray drift, smoke nuisance, odours, dust and industrial emissions.

About 10 complaints are received each year about school incinerators.

When a complaint is received about spray drift, the air quality staff will make contact and try to find out as much information as possible. An inspection of the property is often done, firstly to check if there is a problem.

Evidence may need to be gathered, including foliage, soil and water samples. Damage to crops from spray can take several days to show up.

Samples are sent to specialist laboratories to be analysed. These tests are expensive so they are not done unless there is obvious damage.

Checking on consents

Air quality monitoring of factories and industrial sites is another role of the Northland Regional Council.

Many industries have to obtain resource consents, which are contracts with conditions to meet environmental concerns. As part of these resource consents, industries must be monitored to make sure they are keeping to the conditions that have been set to look after the environment.

Many choose to conduct their own monitoring as this is a cheaper option. The Council checks the results of this monitoring, and also conducts independent tests.

The bigger industries involved include the Marsden Pt Oil Refinery in Whangarei, the cement works, dairy factories and the triboard mill in Kaitaia.

Air consents are also issued for sewage treatment plants catering for groups of houses.

The Council checks more than 200 air consents every year.

Any complaints about an industry are checked and if there are problems found, the industry is required to fix the problem. This may involve the industry having to install air emission control equipment.

State of the Environment Monitoring for air quality

Another area of responsibility for the Northland Regional Council is monitoring the state of the environment.

The data collected from the region helps to show the current air quality and allows these results to be compared against earlier results. This can help the Council keep tabs on any areas that might be getting worse so that steps can be taken to make improvements.

State of the Environment monitoring can include carrying out many different types of tests. 

One test checks how much very fine dust there is in the air. Very fine dust is sometimes called PM10. This dust is so small that it can't be seen with the naked eye.

The particulate matter (PM10) is so fine that it is suspended in the air and can be breathed into the lungs to cause irritation. It can cause breathing problems and asthma attacks. PM10 particles can come from vehicle exhaust fumes and smoky fires.

Another test is for carbon monoxide. This pollutant comes from car exhaust fumes and fires.

A third test is for 6-8 pollutants, collectively. These are mostly manmade and show the effects of humans on the atmosphere. The test traces ozone, nitrous oxide, sulphur dioxide, lead, fluoride and hydrogen sulphide.

Fluoride comes from fertiliser manufacture and can be toxic to plant life. Humans can tolerate a reasonable amount of fluoride - even in our toothpaste - but plants will die from exposure to too much of it.

Hydrogen sulphide can be produced from volcanic activity. It is the 'rotten egg' smell of Rotorua or Ngawha. High concentrations can paralyse a person's sense of smell and eventually kill them.

Lead used to be added to the petrol used in cars. When the petrol was burned the lead was discharged in exhaust fumes. This has significantly reduced with the introduction of unleaded petrol, to the point where it is no longer a problem.

Nitrous oxide is formed from burning combustible matter.

Ozone might be good in the upper atmosphere because it helps to prevent the sun's rays from burning us. However, at ground level and in high concentrations, it can be toxic to humans, animals and plants.

Sulphur dioxide comes from burning fuels that contain sulphur.

Air quality

Air is meant to be invisible, so haziness is a sign that the air quality is not what it should be.

Air quality depends on the amount of pollution and the rate it is dispersed. Poor air quality occurs when winds are very light and the pollution hangs around in the air. This often happens in winter when pollution is trapped close to the ground on calm winter nights by temperature inversions.

Smoky factory chimney.A smoky factory chimney near Port Whangarei. Managing smoke is the responsibility of all parties involved.

Pollution can also be trapped in areas where there are a lot of buildings. Such parts of the city can trap car exhaust fumes, sometimes reaching dangerously high levels.

The rules that exist for air pollution do not allow discharges of large amounts of smoke. If you see a smoky chimney puffing out large amounts of blue hazy smoke, this should be reported to the Northland Regional Council.

This should not be confused with white steam, which is allowed to be discharged. Checking air quality involves checking many different things.

What is in smoke?

Winter time is when many people light a fire in their fireplaces at home. Did you know that smoke from home fires is a significant source of winter air pollution? The problem is especially bad between the hours of 4pm and 10pm because that is when many people are at home. It is also a time when the wind often dies down so that the smoke tends to hang in the air.

Scientists have analysed smoke and found that the chemicals and fine particles in wood smoke can make people sick.

Smoke can contain:

  • Acrolein: Irritates the eyes and respiratory tract;
  • Formaldehyde: Can cause headaches, respiratory tract irritation and cancer;
  • Carbon monoxide: Can cause angina in people with heart disease and if enough is inhaled, can kill people;
  • Nitrogen oxides: Can cause bronchial congestion, fluid congestion and fibrotic changes to the lungs;
  • Fine dust (particulate): Can aggravate asthma;
  • Volatile organic compouds: Can cause respiratory illness and some, like benzene, can cause cancer; and
  • Polycyclic aromatic hydrocarbons: Prolonged exposure is believed to carry a risk of cancer.

The key to a good fire is less smoke. Use kindling and paper to start the fire and get a good bed of embers underway before putting on bigger pieces of wood. There will always be some smoke when a fire is started, but this should not last for more than 20 minutes.

Keeping the chimney clean will also help the fire burn more efficiently and with less smoke.

Discoloured smoke.The discoloured smoke indicates problems with the discharges from this factory. 

Major air pollutants

Pollutant Source What effect does it have?
Carbon Monoxide
A colourless, odourless, tasteless and relatively inert gas which slowly converts to carbon dioxide over a period of about a month.
  • Vehicles burning petrol
  • Domestic fires
  • Interferes with the ability of the blood to absorb and circulate oxygen.
  • Can affect people with heart conditions and can impair co-ordination and attention.
  • Causes headaches and vomiting.
  • Large amounts can kill.
Nitrogen Dioxide
A reddish, brown, pungent, acidic gas.
  • Vehicles burning diesel or petrol
  • Domestic fires
  • Power stations burning fossil fuels
  • Major industry
  • Lightning
  • Can lead to throat and lung infections.
  • Low level exposure can affect growth and cause damage to plants.
  • Contributes to the formation of hazes and smog.
A colourless gas with a distinctive pungent odour like electricity burns. It forms under certain conditions when nitrogen oxides and volatile organic compounds react in the presence of sunlight.
  • Vehicle exhaust fumes
  • Formed from other air pollutants in the presence of sunlight
  • Can seriously damage plants and animals
  • Causes runny eyes, nose and throat irritation and breathing difficulties.
  • Affects the functioning of the heart.
Sulphur Dioxide
A colourless, pungent, acidic gas which readily reacts in the air to form sulphuric acid and other compounds. It is usually oxidised in the air within a few days.
  • Vehicles burning diesel
  • Coal burning
  • Power stations and industries
  • Oil refineries
  • Irritates the lungs
  • Is toxic to some plants and is corrosive to building surfaces and metals in moist conditions.
  • Is a major contributor to acid rain in the Northern hemisphere.
Fine particulate (dust)
This is not visible to the human eye but does create a visible haze in the air.
  • Diesel engines
  • Industry
  • Windblown dust
  • Domestic fires
  • Backyard burning
  • Power plants
  • Can be inhaled into the throat and lungs.
  • Can lead to asthma, bronchitis and lung disease.
  • Can carry carcinogenic materials into the lungs
  • Affects visibility by creating a haze, and can contribute to the soiling and corrosion of buildings.


Backyard burning

There are rules about backyard burning. While people are allowed to light a fire, they are not allowed to make a smoke nuisance. Throwing anything on to burn is not acceptable. Some things are extra toxic or dangerous and should not be burnt.

These items give off toxic fumes:

  • Rubber (including tyres)
  • Treated timber
  • Plastics
  • Chemical containers
  • Coated metal cable
  • Motor vehicles or parts of motor vehicles.

These items create lots of foul-smelling smoke:

  • Green grass and foliage
  • Food scraps
  • Vacuum cleaner dust
  • Wet material.

These items will not burn and could explode:

  • Tins or glass containers
  • Aerosol cans.

Fires should be lit well away from boundary fences, any building or anything that could burn.

Fires should not be lit between sunset and sunrise.

Have water nearby such as a garden hose.

Make sure the fire is supervised at all times

Check that smoke isn't causing a nuisance to neighbours by blowing over their washing or into their homes.

Burn small amounts of rubbish at a time to cut down on smoke.

Use a clean, well ventilated incinerator.

Instead of backyard fires, it is better to reduce the amount of rubbish the family creates, reuse useful items and compost food and green waste for use in the garden.  The rest of the rubbish is best disposed of at a landfill station.

Air quality equipment

Measured noses: Odours are some of the most difficult and frustrating complaints to deal with. Council air quality staff first have to figure out what the smell is - or even if there is a smell at all.

Because odours are floating through the air, they can be very difficult to trace. They can also dissipate quickly, making the task of investigating a complaint all the more difficult. Big factory sites are difficult because there are so many places from which an odour can come. It helps to know about factory processes to be able to check the most likely places first.

The Northland Regional Council uses a range of equipment to test air quality. 
A special laboratory specialising in olphactometry (measuring the sense of smell) tests how strong a person's sense of smell is. There are laboratories in Auckland and Christchurch that can conduct these tests, which are like a warrant of fitness for the noses of air quality officers.

Air quality monitoring station.Air quality monitoring station at Takahiwai.
Children tend to have better senses of smell than adults. The ability to detect odours also changes according to moods and the type of food that has been eaten.

Try testing your sense of smell in the classroom - perhaps using a blindfold to smell different things. Find who has the best sense of smell!

Other equipment: Testing also involves the use of some highly technical equipment.

A deposition gauge traps particles from the air that are larger than 20 microns - which means they are still too small to be seen with the naked eye. This piece of equipment measures what drops out of the air.

PM10 gauges are used to measure the tiny particulate matter that is much smaller. There is a Hi Vol gauge which sits on the rooftop of the Northland Regional Council's offices in Robert St, Whangarei. This central city site is close to the major vehicle activity of the city so is a good measuring spot.


A portable Mini-Vol air testing device.A portable Mini-Vol air testing device.
A portable version of this piece of equipment is the Mini-Vol. This can be taken out to sites from which complaints have originated for collecting evidence. The Council has four of these machines and they are often used at the boundaries of factories or on dusty roads.

These machines work like very fine vacuum cleaners sucking in air and trapping fine particulate matter on white filters. These quickly turn black with the fine dust captured from car exhaust fumes.

The filters are weighed before and after exposure to the dust - with extremely fine weighing scales.





Under the microscope

Tiny wood fibres.Tiny wood fibres like these taken from an air sample can cause air complaints. Air quality tests can gather tiny pieces of evidence to give clues about where the air pollution is coming from. This helps the air quality staff find out if complaints are warranted and if action needs to be taken. When the samples are studied under the microscope, staff can sometimes tell what the source of pollution is and then trace this back to its source.

For example, complaints were received from a Northland community about tiny bits of matter falling out of the sky and coating cars. Samples were taken and the matter was studied. It was found to be tiny wood fibres, which staff were able to trace back to a Northland timber mill where problems had arisen.

A microscopic view of pollen.A microscopic view of pollen, a common source of complaint.
In another case, a woman had complained about a black soot coating her windows. After microscopic analysis, the "soot" turned out to be mildew.

Complaints are often received about a yellow dust in the air in Northland at certain times of year. This can be shown under a microscope to be pollen.




What can you do?

Use your senses to check out air pollution. One of the best places to start is with minimising rubbish.

vehicle exhaust.Vehicle exhaust is a major cause of air pollution.
Check what your school does to get rid of its rubbish. If there is an incinerator, research different ways of rubbish disposal and start a campaign to make your school more environmentally friendly.

The Northland Regional Council receives about 10 complaints a year about school incinerators. The smoke from incinerators can cause problems because it is often in densely settled areas and sometimes unsuitable rubbish such as food scraps are burnt, which create a lot of smoke. Many schools in Northland are looking at how they can reduce waste. Make it a project for your school, too!

Robert Saunders with his air pollution project.Year 7 student Robert Saunders, of Pompallier College, Whangarei, with his air pollution project. Robert found Smeatons Dr was one of the dustiest areas of the city.

Check the symbols on plastic cartons. The numbers within a triangular shape give clues to how the plastic should be disposed of. A number 2 inside the triangle indicates the plastic is safe to burn. A number 1 or 3 indicates burning the plastic would give off toxic gases.

Check the amount of dust and dirt in your environment by looking at what has collected on the trees in your area.

Select some trees, and wipe a leaf from each with a slightly damp cotton wool ball. Decide on a scale to measure which leaf is dirtiest and which is cleanest. Try to discover where pollution on the leaves might be coming from.

A lot of pollution comes from cars. You or your parents can help the environment by keeping the car well tuned to reduce pollution from exhaust fumes. Vehicles should not be emitting blue, white or black smoke.

Car pooling reduces the number of cars on the road. If each car produces about 2kg of pollution per 35km, how much pollution have you generated in a week?

Get your chimney checked and cleaned regularly. Do not burn wet wood, green wood, household rubbish, coal, painted wood, cardboard or driftwood. Many of these give off a lot of smoke. Painted wood can give off dangerous chemicals and driftwood contains sea salts that can damage the wood burner.

Save heat in the house by closing curtains at dusk. Shut the doors in the lounge or whichever room you are heating. Insulate floors, ceilings and walls. These measures will cut down on pollution and save money as well!

Study air pollution as part of science projects. One Northland student, Robert Saunders of Pompallier College in Whangarei, won two prizes at the Central Northland Science and Technology Fair with his study of ``Rain or Shine, There's Dust, Dirt and Grime''.

His project won the Central Northland Research Award and the Year 7 Investigation Award.

Robert's science fair project started after his mother had commented that she thought there was more dust in Raumanga, where they live, than other parts of the city. Robert set out to find out if that was true.

He found this hypothesis was true, especially in the Smeatons Drive area. He found dust was coming from a lot of truck movements and quarry activity.

The rest of Whangarei had relatively good air quality. However, there was a lot of pollen in the air. Of the air pollution he did find, soot was the main component apart from pollen.

Many schools are looking at recycling, including the students from Morningside Primary School pictured below. Check out recycling options and try to eliminate burning of rubbish at your school.

Morningisde Primary School.Morningside Primary School pupils in the old bath that's now a worm farm on the new recycling centre site set up as part of their aim to get rid of the school incinerator.

Sources: Northland Regional Council staff, Northland Regional Council Regional Policy Statement, Auckland Regional Council air quality resource kit.