Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
what is the regulatory citation when the standard is 15 μg/m³?

### Inputs:
table_name: table, columns: ['Pollutant', 'Type', 'Standard', 'Averaging Time', 'Regulatory Citation']

### Response:
SELECT Regulatory Citation FROM table WHERE Standard = 15 μg/m³