ALBERTA AMBIENT AIR QUALITY OBJECTIVES AAACCCRRRYYYLLLOOONNNIIITTTRRRIIILLLEEE Characteristics Acrylonitrile (CAS No. 107-13-11), a volatile and flammable gas, is a colourless to slightly yellow liquid at ambient temperature and pressure. Its odour has been described as sweet and faintly pungent, resembling that of peach seeds, onion and garlic, or mustard. Acrylonitrile is used primarily in the fabrication of acrylic fiber, resins, rubbers and elastomers. Emissions of acrylonitrile from the industrial facilities in Alberta have been below the criteria for reporting to the National Pollutant Release Inventory. Since the half-life is of the order of days, acrylonitrile may disperse from the source areas. In the atmosphere it undergoes a photochemical reaction with hydroxyl radicals and produces mainly formaldehyde and, in lesser amounts, other compounds such as formic acid, formyl cyanide, carbon monoxide, and hydrogen cyanide. The detection limit for measurements in ambient air is 0.5 ppb by the US Environmental Protection Agency Compendium Method TO15-A. Effects No published literature could be found on the direct effects of acrylonitrile exposure to terrestrial plants (WBK & Associates Inc., 2002). The primary pathway of acrylonitrile exposure for the general public and animals is through inhalation. Adverse human health responses, including eye and throat irritation, central nervous system effects (e.g. headaches, nausea, vomiting, convulsions and unconsciousness) and death, have been reported in humans after accidental acute exposure via inhalation and/or skin contact. However, corresponding dose (exposure concentrations and durations) associated with these events are not known with a great deal of certainty. Animal studies indicate that at concentrations from 58 to 1,330 mg m-3 (26 to 600 ppm), over exposure durations from 4 hours to 60 hours (on an intermittent basis), acute, short-term exposures of acrylonitrile cause salivation, tearing of the eyes, diarrhea, gastrointestinal injury, seizures, and death. Chronic, long-term exposures have been demonstrated to cause cancers in a number of rat studies, including tumor formation in the brain and spinal cord, small intestine, tongue, zymbal gland and mammary glands. Air concentrations associated with these cancers ranged from 45 to 178 mg m-3 (20 to 80 ppm) for exposure durations of one to E FFECTIVE J ANUARY 1, 2004 - 2 - two years (on an intermittent basis). Conclusive results cannot be drawn from long-term human exposure in occupational settings because of confounding factors such as exposure to other chemicals, and lifestyle factors such as smoking. Notwithstanding, the US Environmental Protection Agency used data from these studies to represent incidence of respiratory cancers in humans corresponding to 33 mg m-3 (15 ppm) as an 8-hour time weighted average concentration for an average exposure duration of 9 years. Irritation of eyes and skin; developmental, neurological, respiratory and systemic effects, and even death have been demonstrated in rat studies with air concentrations ranging from 45 to 178 mg m-3 for exposure durations of one to two years (on an intermittent basis). Acrylonitrile has been considered to be a potential carcinogenic to humans due to evidence of carcinogenicity in rat studies. Objectives in Other Jurisdictions Air quality objectives set by the agencies reviewed in the assessment report ranged from: 180 µg m-3 (83 ppb) for 30 min; 43 µg m-3 (19 ppb) for 1-hour; 0.6 to 217 µg m-3 (0.3 to 98 ppb) for 24-hour; and 0.01 to 4.3 µg m-3 (0.005 to 1.9 ppb) for annual. For acute, short-term exposure, the Texas Natural Resource Conservation Commission uses a 1-hour average value of 43 µg m-3 (19 ppb) determined from dividing the Threshold Limit Value of the American Conference of Governmental Industrial Hygienists (an 8-hour time weighted average occupational exposure limit of 4,300 µg m-3) by a safety factor of 100. For chronic, long-term (≥ 1 year) objectives, the California Environmental Protection Agency, the New Hampshire Department of Environment Service, the New Jersey Department of Environmental Protection, and the Wisconsin Department of Natural Resource all use the reference concentration of 2 µg m-3 (0.9 ppb) developed by the US Environmental Protection Agency. Alberta Ambient Air Quality Objectives Based upon the available information, Alberta hereby adopts: from Texas - an acute, short-term Alberta Ambient Air Quality Objective for acrylonitrile of 43 µg m-3 (19 ppb) as a 1-hour average concentration, and from California - a chronic, long-term Alberta Ambient Air Quality Objective for acrylonitrile of 2 µg m-3 (0.9 ppb) as an annual average concentration. Reference WBK & Associates Inc., 2002: Assessment Report on Acrylonitrile for Developing an Ambient Air Quality Guideline. Prepared for Alberta Environment. Edmonton, Alberta, Canada. 61 p. E FFECTIVE J ANUARY 1, 2004 .