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Subpart 257-7: Air Quality Standards-Nitrogen Dioxide (No2)

(Statutory Authority: Environmental Conservation Law, § 15)

[Filed 5/19/72. Effective 30 days after filing.]

[This is page 1 of 1 of this Subpart. A complete list of Subparts in this regulation appears in the Chapter 3 contents page. A list of sections in this Subpart appears below.]

For administrative information about this posting, contact: Division of Air Resources. The Bureau of Air Quality Planning at (518) 402-8396 or the Bureau of Stationary Sources at (518) 402-8403 is the contact for technical questions pertaining to this rule.



§257-7.1 Characteristics

Nitrogen dioxide is a reddish-orange-brown gas with a characteristic pungent odor. The partial pressure of NO2 in the atmosphere restricts it to the gas phase at usual atmospheric temperatures. It is corrosive and highly oxidizing and may be physiologically irritating. The presence of nitrogen dioxide in ambient air has been associated with a variety of respiratory diseases. NO2 is essential to the production of photochemical smog. At higher concentrations, its presence has been implicated in the corrosion of electrical components as well as vegetation damage.

§257-7.2 Objective

The objective of this Subpart is the attainment of the annual average which, with an adequate safety margin, will provide for protection of public health and will protect against known and anticipated adverse effects on public welfare.

§257-7.3 Standard

During any 12 consecutive months, the annual average of the 24-hour concentrations, shall not exceed 0.05 ppm (100 µg/m3) in all levels.

§257-7.4 Measurement

(a) The concentration of NO2 is determined by the method specified or by an equivalent method approved by the commissioner.

(b) NO2 is collected in a sodium hydroxide solution and determined colorimetrically by reacting the exposed absorbing reagent with phosphoric acid, sulfanilamide, and N-1-naphthylethylenediamine dihydrochloride.

(c) All measurements are corrected to a reference temperature of 25 degrees Centigrade and to reference pressure of 760 millimeters of mercury.