Appendix 5 – Air Quality Impact Assessment Methodology

Major Adverse

‘With development’ results in an increase in concentrations over ‘without development’ concentrations of greater than 1 µg/m³ or 2.5%; where ‘without development’ concentrations are predicted to exceed the 40 µg/m-³ objective limit value; or

‘With development’ results in increases in concentrations greater than 1 µg/m³ or 2.5% that are predicted to cause exceedance of the 40 µg/m-³ objective limit value; where WITHOUT development concentrations are NOT predicted to exceed 40 µg/m-³ objective limit value; or

‘With development’ results in an increase in concentrations over ‘without development’ greater than 25%.

Moderate Adverse

‘With development results in an increase in concentrations over ‘without development’ concentrations of less than 1 µg/m³ or 2.5%; where ‘without development’ concentrations are predicted to exceed the 40 µg/m-³objective limit value;

‘With development’ results in an increase in concentrations over ‘without development’ of greater than 10% but less than 25%

Minor Adverse

‘With development’ results in an increase in concentrations over ‘without development’ concentrations of greater than 2.5% but less than 10%

No significance / insignificant

‘With development’ results in a change in concentrations over ‘without development’ concentrations of less than 1 µg/m³ or 2.5%

Minor beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 2.5% but less than 10%.

Moderate beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 10% but less than 25%.

Major beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 25%

Major Adverse

With development results in an increase in concentrations over without development concentrations of greater than I µg/m³ or 2.5%; where without development concentrations are predicted to exceed the 40 µg/m³ objective limit value or

With development results in increases in concentrations greater than 1 µg/m³ or 2.5% that are predicted to cause exceedance of the 40 µg/m³ objective limit value; where without development concentrations are not predicted to exceed 40 µg/m³ objective limit value

With development results in an increase in concentrations over without development greater than 25%

Moderate Adverse

With development results in increases in concentrations greater than 1 µg/m³ or 2.5% but the actual concentration does not cause an exceedance of the 40µg/m³ objective limit or

With development results in an increase in concentrations over without development concentrations of less than 1 or 2.5%; where without development concentrations are predicted to exceed 40 µg/m³objective limit value or

With development results in an increase in concentrations over without development greater than 10% but less than 25%

Minor Adverse

With development results in an increase in concentrations over without development concentrations of greater than 1µg/m³ or 2.5% but less than 10%

No significance/ insignificant

With development results in concentrations over without development concentrations of less than 1 µg/m³ or 2.5%

Minor beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 1µg/m³ or 2.5% but less than %

Moderate beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 10% but less than 25%

Major beneficial

With development results in a decrease in concentrations over without development concentrations of greater than 25%

NOTES

Where air quality impacts meet multiple criteria, the higher significance class will be applied.

The location has little ability to absorb change without fundamentally altering its present character, or is of international or national importance.

The location has moderate capacity to absorb change without significantly altering its present character, or is of high importance.

The location is tolerant of change without detriment to its character, is of low or local importance.

Major Adverse/Beneficial

Major – Moderate Adverse/Beneficial

Moderate – Minor Adverse/Beneficial

Major – Moderate Adverse/Beneficial

Moderate – Minor Adverse/Beneficial

Minor Adverse/Beneficial

Moderate – Minor Adverse/Beneficial

Minor Adverse/Beneficial

Minor – Negligible

Negligible / Insignificant

Negligible / Insignificant

Negligible / Insignificant