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Leading and involving the Southland community in managing our natural resources of air, water, land and coast in order to protect and enhance the lifestyle and well-being of current and future generations.

Air

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Air Quality - What are the Issues?

• Localised air quality issues associated with odours, dust, smoke, agrichemical spray and other discharges to air from the domestic, transport, commercial, agricultural, horticultural, manufacturing and industrial sectors.
• Ambient air quality issues related to wintertime air pollution in urban areas with its associated health effects and nuisance effects (e.g., reduced visibility, and dust or odour nuisance) resulting from combustion processes.
• Global air quality issues connected with the reduction in the ozone layer and with greenhouse gas emissions and consequential global warming.

What about Southland's Air Quality?

There is a widely held belief that air quality in Southland, and particularly Invercargill, is not a problem. Given our relatively windy climate, this assumption is not surprising. However, as we are now learning, the air quality in some of our towns is not always as clean as we might think.

Since Environment Southland commenced monitoring of PM10 in Invercargill, the maximum guideline level of 50 µg/m3 has been exceeded a number of times.

As we see in both Invercargill and Gore, the exceedances occur between mid-May and mid-August, the period when home heating is at a maximum. It is also a time of year when we tend to get periods of settled weather, with cool and windless nights; ideal conditions for the build up of ₁₀ emissions from home fires.

Summary of PM₁₀ Concentrations Measured in Invercargill from 2003 to 2008

	2003	2004	2005	2006	2007	2008
"Good" 0-33% of Guideline	44%	45%	64%	60%	73%
"Acceptable" 33-66% of Guideline	36%	33%	21%	29%	22%
"Alert" 66-100% of Guideline	13%	18%	10%	10%	4%
> Guideline	7%	5%	5%	1%	1%
Percentage of Valid Data	15%	28%	28%	67%	98%
Annual Average (µg m-3)		19	20	15	14
NES Breaches	14	10	10	1	2
Annual Maximum (µg m-3)	90	88	198	56	63
Number of Records	55	101	101	244	356

Summary of PM₁₀ Concentrations Measured in Gore from 2005 to 2008

	2005	2006	2007	2008
"Good" 0-33% of Guideline	22%	56%	74%
"Acceptable" 33-66% of Guideline	48%	34%	24%
"Alert" 66-100% of Guideline	22%	6%	2%
> Guideline	8%	4%	0%
Percentage of Valid Data	23%	65%	99%
Annual Average (µg m-3)	21	16	13
NES Breaches	12	7	0
Annual Maximum (µg m-3)	102	72	49
Number of Records	86	239	360

What does this Guideline Mean?

These values class our monitoring data into “bands” of information. The information shows us that when a site spends a great deal of time in Alert or above guideline levels we have an Air Quality problem to do further monitoring or a detailed investigation into what’s causing air pollution.

Environmental Performance Indicator categories for air quality (MfE, 2002):

Category	Value Relative to Guideline	Comment
Excellent	Less than 10% of the Guideline	Of little concern: if maximum values are less than a tenth of the guideline, average values are likely to be much less
Good	Between 10% and 33% of the Guideline	Peak measurements in this range are unlikely to affect air quality
Acceptable	Between 33% and 66% of the Guideline	A broad category, where maximum values might be of concern in some sensitive locations but generally they are at a level which does not warrant urgent action
Alert	Between 66% and 100% of the Guideline	This is a warning level, which can lead to exceedences if trends are not curbed
Action	More than 100% of the Guideline	Exceedences of the guideline are a cause for concern and warrant action, particularly if they occur on a regular basis

Percentage of Valid Data
This shows you how much data we have gathered as a % of total hours of data – the higher the percentage the more data we have to make informed decisions from.

Annual Average (µg m-3)
This is the value representing the average measured through the year at the site monitored. If this value decreases over time it indicates overall Air Quality has improved.

NES Breaches
This is the number of official breaches of the National Environmental Standard for pm10.

Annual Maximum (µg m-3)
This is the highest value we have measured over a calendar year.

Number of Records
This is the number of 24 hour values (days) we have complete data for.

What is Environment Southland Doing?

Environment Southland commenced an air quality monitoring programme in Invercargill in June 2003, with an identical programme starting in Gore in 2005. The monitoring is focused on ₁₀, because our analysis of the risks suggested that this would be the issue of most concern for Southland Air Quality.

Over the few years, monitoring will be extended throughout Southland. Towns already monitored include Edendale, Mataura. Bluff and Winton. One years monitoring showed that Air Quality guidelines for PM10 were not exceeded in Edendale, Mataura and Bluff (see Air Quality Report Card). Winton is being monitored a second year because of concerns about a high annual level of PM10, even though the area did not exceed the NES.

Air

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• Air Quality Monitoring
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Related information

Other sections that may interest you:

• Air Quality Plan
• Applying for a Burning Consent
• Monitoring Report Cards

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