Bay of Plenty Regional Council is required to undertake
monitoring activities as part of its statutory responsibilities
under the Resource Management Act 1991. The Natural
Environmental Regional Monitoring Network (NERMN) is based around a
regional network of monitoring sites designed for regional
state-of-the environment monitoring, documentation and reporting.
Natural environment monitoring determines the overall regional
impact of activities on environment quality.
A new Regulation for ambient air quality in New Zealand was
promulgated in September 2004, as a National Environmental Standard
(NES) under s43 of the Resource Management Act 1991. The NES
specifies health-based limits for ambient air concentrations of
fine particulate (PM10), carbon monoxide, nitrogen dioxide, ozone
and sulphur dioxide. The Regulation also specifies
requirements for monitoring of these pollutants, in the event that
the standards are breached.
Current Monitored Contaminants
The following air contaminants are currently monitored by Bay of
Plenty Regional Council.
Carbon monoxide is a poisonous gas. Prolonged exposures at
moderate concentrations can cause headaches and dizziness.
Chronic exposure at lower levels has been linked to an increased
incidence of heart disease.
The air quality guidelines for carbon monoxide were exceeded on
a number of occasions in the past in Tauranga (Nichol et.
al.,1996), which indicates that air quality is already being
compromised. This was recognised in the Operative Regional
Air Plan released by Bay of Plenty Regional Council, and a number
of actions were proposed for dealing with this issue. Carbon
monoxide monitoring is therefore an important component of the Air
NERMN programme, to determine the current extent of any
problem, and any improvements that occur as the result of any
regional (or national) initiatives.
Particulate Matter (PM10)
There is increasing concern throughout the world about the
possible health effects of coarse particulate matter. These
are defined as particulate matter less than 10 µm in diameter,
although in some countries more emphasis is now being placed on the
smaller fraction (termed fine particulate matter), less than 2.5 µm
(PM2.5) in diameter.
Particulate size comparisons
In New Zealand the main source of PM10 emissions in most areas
during the winter months is solid fuel burning for domestic
heating, although industrial contributions may also be significant
in a number of locations. Domestic home heating is also
responsible for the majority of the PM2.5 emissions in most
locations as most of the PM10 emissions from this source are the
smaller PM2.5 size fraction. Motor vehicle emissions may also
be a major source of PM10 and PM2.5 in Auckland, although further
work is being carried out to assess this.
The characteristics, sources and potential health effects of
larger or "coarse" particles and smaller or "fine" particles are
very different. Coarse particles come from sources such as
windblown dust from exposed surfaces such as building sites and
unsealed roads, from mines and quarries, and some industrial
activities. Fine particles are generally emitted from
activities such as industrial and residential combustion, and from
vehicle exhaust. Fine particles are also formed in the
atmosphere from gases such as sulphur dioxide, nitrogen oxides and
volatile organic compounds that are emitted from combustion
processes and become particles because of chemical transformations
in the air.
Coarse particles can deposit in the upper regions of the human
respiratory system and may contribute to health effects such as
bronchitis and aggravation of asthma.
Fine particles can deposit deeply in the lungs, and are therefore
more likely to contribute to a range of health effects, which have
been found in a number of recently published epidemiological
These effects include the following:
- Increased hospital admissions and emergency room visits due to
- Aggravated asthma
- Acute respiratory symptoms including severe chest pain and
- Chronic bronchitis
- Decreased lung function which can be experienced as shortness
- Premature death.
It is therefore important for Bay of Plenty Regional Council to
continue to develop a good understanding of the current levels of
airborne particulate matter throughout the region, as part of the
Air NERMN programme. Measurements are being mainly directed
at urban areas because the major contributors are likely to be
motor vehicles and residential heating using solid fuel fires,
especially wood burners.
The smell of hydrogen sulphide (H2S) is an obvious feature of
New Zealand geothermal areas, most of which are found in the Bay of
Plenty. This gas is very toxic at high concentrations, but
little is known about its health effects at the lower levels found
in most parts of Rotorua and other geothermal areas.
Field monitoring data shows that geothermal activity in Rotorua
has increased over the last few years, probably as a result of the
reduced abstraction rates and more re-injection. If this
trend continues it will be important to determine whether hydrogen
sulphide levels in the ambient air are also being affected.
Nitrogen dioxide is not usually released directly into the air.
Nitrogen dioxide forms when nitrogen oxide (NO) and other nitrogen
oxides (NOx) react with other chemicals in the air to form nitrogen
The main source of nitrogen dioxide resulting from human
activities is the combustion of fossil fuels (coal, gas and oil),
especially petrol and diesel used in motor vehicles. Other
sources of nitrogen dioxide include the refining of petrol and
metals, commercial manufacturing, and food manufacturing. Natural
sources of other nitrogen oxides include volcanoes and
The main health effect of nitrogen dioxide is on the respiratory
system. Inhalation of nitrogen dioxide by children increases their
risk of respiratory infection and may lead to poorer lung function
in later life. There is also an association between nitrogen
dioxide concentrations in the air and increases in daily mortality
and hospital admissions for respiratory disease. Nitrogen dioxide
can decrease the lungs' defences against bacteria, making them more
susceptible to infections, and can also aggravate asthma.
Sulphur dioxide is produced mainly from the combustion of fossil
fuels that contain sulphur, such as coal and oil (for example, coal
being burnt in a home fireplace for heating and diesel-powered
vehicles). Sulphur dioxide is also produced from some
industrial processes, such as fertiliser manufacturing.
Natural sources of sulphur dioxide include geothermal
Sulphur dioxide can cause respiratory problems, such as
bronchitis, and it can irritate the nose, throat and lungs. It may
cause coughing, wheezing, phlegm and asthma attacks. The effects
are worse during exercising.
The latest Environmental Publication 2012 02 NERMN Air
Monitoring 2012 (PDF, 632kb) programme reports on air
quality data collected to date, it also includes a review of the
monitoring programme and provides guidance and recommendations as
to the future direction of this programme