Question: what is the averaging time when the regulatory citation is 40 CFR 50.4(b)?
SQL: SELECT "Averaging Time" FROM "2-1621705-1" WHERE "Regulatory Citation" = '40 CFR 50.4(b)';

Question: what is the regulatory citation when the standard is 15 μg/m³?
SQL: SELECT "Regulatory Citation" FROM "2-1621705-1" WHERE "Standard" = '15 μg/m³';

Question: what is the standard when the pollutant is O 3 and averaging time is 8-hour?
SQL: SELECT "Standard" FROM "2-1621705-1" WHERE "Pollutant" = 'O 3' AND "Averaging Time" = '8-hour';

Question: what is the polluntant when the regulatory citation is 40 CFR 50.7(a) and the type is Primary?
SQL: SELECT "Pollutant" FROM "2-1621705-1" WHERE "Regulatory Citation" = '40 CFR 50.7(a)' AND "Type" = 'Primary';

Question: what is the type when the averaging time is 1-hour and the standard is 0.12 ppm (235 μg/m³)?
SQL: SELECT "Type" FROM "2-1621705-1" WHERE "Averaging Time" = '1-hour' AND "Standard" = '0.12 ppm (235 μg/m³)';

Question: what is the type when the regulatory citation is 40 CFR 50.9(a)?
SQL: SELECT "Type" FROM "2-1621705-1" WHERE "Regulatory Citation" = '40 CFR 50.9(a)';