CREATE TABLE "standards" (
  "pollutant" text,
  "type" text,
  "standard" text,
  "averaging_time" text,
  "regulatory_citation" text
);

Question: what is the averaging time when the regulatory citation is 40 cfr 50.4(b)?
SQL: SELECT "averaging_time" FROM "standards" 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 "standards" 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 "standards" 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 "standards" 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 "standards" 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 "standards" WHERE "regulatory_citation"='40 cfr 50.9(a)';