Ammonia is a common by-product of animal waste. The volume of ammonia emissions depends on manure characteristics and how the manure is managed.

Ammonia emissions are an environmental concern because they can adversely impact water and air quality. Ammonia emissions can contribute to eutrophication of surface waters and nitrate contamination of ground water. In addition, when emitted ammonia is combined with acidic compounds in the upper atmosphere, fine dust particles (particulates) capable of being inhaled are formed. These particulates have been related to atmospheric haze, and also have been attributed to a variety of adverse human health effects, including premature mortality, chronic bronchitis, asthma, and other respiratory ailments.

The PBR applies to dairy farms with a capacity to produce 100 or more tons of ammonia emissions per year. (Dairy farms with fewer than the specified number of animal units or mature cows may opt into the PBR program as well.) The capacity to produce is based on the number of animal units or mature cows and the type of manure collection system. The table below shows the applicable thresholds prescribed in the rule:

1  Assumes expected level of N->NH3 volatilization for drop-hose or ground level liquid manure application.

2  Assumes expected level of N->NH3 volatilization for center pivot or other conventional sprinkler irrigation liquid manure application.

Within 30 days of receiving a dairy farm's registration information, ISDA will conduct an inspection to ensure that the required number of BMPs are employed. ISDA will also provide compliance assistance if needed. If ISDA finds that BMPs are lacking, it may issue a warning letter.

Enforcement of the rule is DEQ's responsibility. Enforcement methods include filing a notice of violation or refering the case to the Attorney General's office for civil enforcement. In the event of unforseen equipment upsets and breakdowns, DEQ will exercise enforcement discretion. So long as corrective action is taken within a reasonable time, which would depend on specific circumstances, the event will not reduce the BMP point value. In the event of an emergency, the farm could apply for and be granted an exemption for up to one year.