40 CFR §63.3173

1. (a)To demonstrate continuous compliance with the applicable emission limit in § 63.3090(b) or § 63.3091(b), the organic HAP emission rate for each compliance period determined according to the procedures in § 63.3171 must be equal to or less than the applicable emission limit in § 63.3090(b) or § 63.3091(b). A compliance period consists of 1 month. Each month after the end of the initial compliance period described in § 63.3170 is a compliance period consisting of that month. You must perform the calculations in § 63.3171 on a monthly basis.
2. (b)If the organic HAP emission rate for any 1 month compliance period exceeded the applicable emission limit in § 63.3090(b) or § 63.3091(b), this is a deviation from the emission limitation for that compliance period and must be reported as specified in §§ 63.3110(c)(6) and 63.3120(a)(6).
3. (c)You must meet the requirements of § 63.3163(c) through (j).