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3.4 Proposed ambient standards

3.4.1 Particles (PM10)

Air Quality Technical Report Number 46, Section 2.3, proposed the following:

The proposed standard for fine particles (less than 10 microns in diameter - PM10) is:

  • 50 µg/m3 (one-day average) with a maximum of five days per year on which the standard can be exceeded up to a maximum limit of 120 µg/m3 (one-day average).

The proposed monitoring method is US 40 CFR Part 50, Appendix J, or an equivalent method. Where a tapered elemental oscillating microbalance (TEOM®) is used, it should be co-located with another sampling method, such as a high-volume sampler, to determine an appropriate conversion factor.

Submissions received in relation to the proposed PM10 standard are summarised below.

Submitter 3 wants the standard to make it explicit that all naturally occurring particulate concentrations are excluded from the data used to determine compliance with the standard.

Submitters 6, 163 and 174 note that the weight of evidence relating to the health effects of particles is such that it is appropriate to aim for levels below the current guideline of 50 µg/m3. These submitters do not support the concept of an absolute maximum and consider there is no justification for setting such a level at 120 µg/m3, particularly because this value was replaced in the 2002 Guidelines based on the latest information on the health effects of particulates. The submitters consider that because there are known health effects below the standard of 50 µg/m3 there is good reason not to allow any exceedances.

Submitters 6, 72, 75, 163 and 174 ask that an annual average standard of 20 µg/m3 be included to account for chronic health effects.

Submitter 9 seeks an annual standard for PM10 and/or PM2.5 because daily standards do not guarantee protection of public health.

Submitter 26 seeks an annual standard for PM10 in the vicinity of 25 µg/m3. The submitter also wants the standards to be set/applied bearing in mind the actual exposure scenario.

Submitter 31 asks that the Ministry undertake ongoing research into different sources of inhaleable particulate to evaluate whether contributions from sources such as sea salt should be included or excluded.

Submitter 36 supports the standard.

Submitter 72 is concerned that the wording of the standard assumes that daily readings are being collected, which necessitates continuous-monitoring equipment. The submitter wants the standard to be reworded to allow for high-volume samplers using the one-day-in-six or one-day-in-three rotation. The submitter notes that the reduced frequency of monitoring would necessitate the number of exceedance allowances to reduce.

Submitter 72 seeks an exclusion to the standard for excessive PM10 associated with dust from gravel roads, because monitoring in the vicinity of such roads has shown levels in the range 300 to 800 µg/m3, which would require continual notification by the council, who they have little control over these sources.

Submitter 89 opposes the standards with special reference to PM10. The submitter considers that the current state of knowledge does not allow a move from guidelines to standards, and requests that if standards are to be promulgated an annual average of 20 or 25 µg/m3 be added.

Submitter 127 is opposed to a standard, but if there is to be a standard requests that it reflect the provisions of the air quality guidelines more closely, and include an annual average value.

Submitter 102 supports the standard and hopes that eventually the number of allowable exceedances will be zero.

Submitter 111 supports the standard and asks that it be retained. The submitter also seeks an education programme aimed at domestic wood suppliers and consumers to support the standard, and asks that central government increase funding for projects that aim to increase the material qualities of wood products and the efficiency of wood-burning appliances.

Submitter 131 wants a PM10 standard to be delayed until a full cost-benefit analysis is provided and the wider social and economic effects on Christchurch can be determined. It is impractical for Christchurch to meet the standard within the four-year timeframe, and considers that the social and economic effects could be significant.

Submitter 138 is opposed to the adoption of the standard for PM10 and asks that it be delayed until the statistical basis for the standard has been examined by a competent actuary, independent of the agencies that have developed these standards.

Submitter 139 requests that the ceiling limit be deleted because it is not practicable, that the term "one-day average" be replaced with "24-hour average", and that a diesel generator being parked next to an ambient air monitor be deleted as an example.

Submitter 145 considers that the proposals are unworkable because while some sophisticated source apportionment techniques can be used, they are not sufficiently precise to be used for measuring compliance with a regulation and will require large studies over long time periods.

Submitter 155 wants existing background concentrations, both natural and human made, to be fully understood before definitive decisions are made about the specific cause. The submitter also wants additional epidemiological research to be conducted and peer reviewed before the estimated premature death rate is used for justification of the standards. The submitter seeks more guidance on natural background concentrations so that the PM10 standard is applied consistently at the local level.

Submitter 156 states that the basis for allowing five exceedances (98.5th percentile) is not clear. A 98th percentile approach equates to seven days per year and has been proposed in the United States and European Union, while the United Kingdom allows 10 exceedances. The standard does not take into account the inability of some areas to achieve the standard in the short term, and considers that different local targets and a staged approach would be more sensible.

Submitter 156 supports the approach of allowing naturally occurring PM10 to be deducted from the ambient measurement, but considers that a standard method should be adopted to ensure regional consistency.

Submitter 161 requests that a standard for PM10 not be specified at this stage, unless it is restricted to combustion particulate in urban areas, because of emerging evidence that ultra-fine particles are more of a concern in relation to health effects.

Submitter 164 queries whether the number of exceedances allowed is based on the one-day-in-six monitoring regime.

Submitter 175 wants PM2.5 to be used as the concentration limit for particles rather than PM10 because the World Health Organisation has acknowledged that there are no discernible effects on health from the size fraction greater than PM2.5.

Submitter 175 comments that justification is required for the maximum limits for key air pollutants, or they should be removed, because the basis on which the values have been selected is not clear. Justification for the number of allowable exceedances is required and that the criteria should be logical and based on New Zealand conditions.

Submitter 175 states that consideration should be given to an annual average standard in addition to the 24-hour standard for PM10, because chronic health effects are correlated with annual average exposures. The submitter considers that the averaging periods for the other gases (NO2) need to be justified and requests that the averaging periods described in the 2002 Guidelines be retained.

Submitter 175 requests that information on the monitoring method used to measure compliance be included in the standard because the monitoring method can have a considerable effect on the number of exceedances recorded.

Submitter 180 opposes the standard on the grounds that it would have a significant impact on the operations of many coal users. The submitter considers that the standard is not justified and that a risk-based approach would be more credible. If a cost-benefit analysis does justify a PM10 standard, the submitter considers that it should include an annual average. The proposed guideline is set at the same level as the most stringent international target, and is concerned that while it is equivalent to the Australian standard of 50 µg/m3 with five exceedances by 2008, the monitoring locations in Australia are neighbourhood sites away from major sources, while the proposed ambient standards will be applied to peak sites in New Zealand with the rationale that it is more equitable, precautionary and protective.

Submitter 184 seeks a deadline for compliance of four years from the date of proposal (ie, November 2007). The submitter has concerns over the proposed allowance of five exceedances per year and suggests this be lowered over time. The submitter wants work to continue to determine whether a standard for very fine particles is required, and seeks a review period for the standards of at least every 10 years.

Submitter 185 seeks more investigation into smaller particles, and considers that towns experiencing PM10 levels above the maximum should be considered for special funding.

Submitters 140, 171 and 201 support the exclusion of sea spray when monitoring compliance but consider that exclusion should be mandatory/explicit and that a similar provision should be added to exclude naturally occurring particulates.

Submitters 133, 154, 185, 206 and 221 seek an annual average standard for PM10.

Submitter 208 considers that exceedances should only be considered to have occurred when a representative sample of ambient air is being taken. An influence such as a diesel generator near the monitor is not representative and should therefore not be counted, and should be deleted as an example.

Submitter 213 wants natural background particulate concentrations to be measured so that the PM10 standard is applied consistently at the local level. The submitter has concerns relating to background PM10 data, PM10 sources and the epidemiological research.

Submitter 221 considers that PM2.5 should be added to the standards and that consideration should be given to fine and ultra-fine particles through research and monitoring programmes. The submitter seeks restrictions on diesel particulate matter to be made a priority. Submitter 221 is also concerned at the reference to "is reasonably consistent with the European Directive value" because this may be used to justify a value of 20 µg/m3 or a 12% margin. The submitter asks that the intention be made clear.

3.4.2 Nitrogen dioxide (NO2)

Air Quality Technical Report Number 46, Section 2.4, proposed the following:

The proposed concentration limit for NO2 is:

  • 200 µg/m3 (one-hour average) with a maximum of nine allowable exceedances (99.9 percentile of one year's monitoring data), up to a maximum limit of 300 µg/m3 (one-hour average).

Submissions received in relation to the proposed NO2 standard are summarised below.

Submitters 6, 163 and 174 are concerned that an unjustified non-health-based approach has been adopted when setting the maximum concentration for breaches. The submitters seek two additional standards as follows:

  • 100 µg/m3 (24-hour)
  • 40 µg/m3 (annual).

Submitter 36 supports the standard.

Submitter 133 seeks an annual average standard for NO2.

Submitter 139 requests that the ceiling limit be deleted because it is not practicable.

Submitter 156 considers the proposed use of the 99.9th percentile to determine the number of allowable exceedances for NO2 and SO2 is too high and should be the 95th or 98th percentile.

3.4.3 Ozone (O3)

Air Quality Technical Report Number 46, Section 2.5, proposed the following:

The proposed concentration limit for O3 is:

  • 150 µg/m3 (one-hour average) with no allowable exceedances; ambient ozone should be monitored using AS3580.6.1 - 1990.

Submissions received in relation to the proposed O3 standard are summarised below.

Submitters 6, 163 and 174 seek an additional standard of 100 µg/m3 (eight-hour average)

Submitter 36 supports the standard.

Submitter 85 wants the number of allowable exceedances for O3 to be set at nine hours per year.

Submitter 164 queries why there are no exceedances allowed for O3.

Submitter 175 notes that no maximum (not to be exceeded) limit has been provided for O3 and CO and requests that a limit be provided or that reasons be provided for not doing so.

3.4.4 Sulphur dioxide (SO2)

Air Quality Technical Report Number 46, Section 2.6, proposed the following:

The proposed standard for SO2 is:

  • 350 µg/m3 (one-hour average) with a maximum of nine allowable exceedances (99.9 percentile of one year of data), up to a maximum limit of 570 µg/m3 (one-hour average).

Submissions received in relation to the proposed SO2 standard are summarised below.

Submitters 6, 72, 163 and 174 seek an additional standard of 120 µg/m3 (24-hour average).

Submitter 36 supports the standard.

Submitter 111 supports the standard in part, but wants the position of natural SO2 released to be clarified.

Submitter 139 requests that the ceiling limit be deleted because it is not practicable.

Submitter 156 considers that the proposed use of the 99.9th percentile to determine the number of allowable exceedances for NO2 and SO2 is too high and should be the 95th or 98th percentile.

Submitter 180 is opposed to the standard on the grounds that it would have a significant impact on the operations of many coal users. The submitter considers that the standard should include an annual average.

Submitter 185 requests that more research be undertaken in relation to the health effects of SO2 even at low levels. The submitter also requests that the synergistic effects of pollutants such as SO2 and NO2 be considered in the standards.

3.4.5 Carbon monoxide (CO)

Air Quality Technical Report Number 46, Section 2.7, proposed the following:

The proposed standard for CO is:

  • 10 mg/m3 averaged over an eight-hour period, with a maximum of nine allowable exceedances and no upper maximum limit.

Submissions received in relation to the proposed CO standard are summarised below.

Submitters 6, 163 and 174 seek clarification on whether the standard is intended to be an -hour moving average calculated hourly or a fixed eight-hour average, and comments that if it is intended to be a fixed eight-hour period then the number of exceedances will not represent the 99.9 percentile.

Submitters 6, 72, 163 and 174 seek an additional standard of 30 mg/m3 (one-hour average).

Submitter 36 supports the standard.