N.Y. Comp. Codes R. & Regs. tit. 6, § 257-3.3 – Standard for suspended particulates.

(d) The standards in subdivisions (a), (b) and (c) of this section are intended for enforcement purposes, and monitoring will be performed only as required in a particular area. For prediction purposes, prediction of conformity with the annual geometric mean standard shall be sufficient to demonstrate predicted conformity with these standards.

(a) 30-day standard.

During any 30 consecutive days, the arithmetic mean of the 24-hour average concentrations, at any location, shall not exceed:

Level I	80 μg/m³	Level III	115 μg/m³
Level II	100 μg/m³	Level IV	135 μg/m³

(b) 60-day standard.

During any 60 consecutive days, the arithmetic mean of the 24-hour average concentrations, at any location, shall not exceed:

Level I	70 μg/m³	Level III	95 μg/m³
Level II	85 μg/m³	Level IV	115 μg/m³

During any 90 consecutive days, the arithmetic mean of the 24-hour average concentrations, at any location, shall not exceed:

Level I	65 μg/m³	Level III	90 μg/m³
Level II	80 μg/m³	Level IV	105 μg/m³