Document YDKQ7gqgrM2wv9wr11NebqjzV

--TjiuLams. in me screening and permu ting process, the AALs have not been employed as strict ambient exposure standards. In general, the states have used the AALs as guides, and if the limit for a pollutant is exceeded then the industry and regulatory agency tend to develop a mutually acceptable plan to reduce ex posure. One difficulty is that the AALs are often derived by a unit or agency other than that which handles the per mitting process (e.g., the Department of Public Health versus the Department of Environmental Protection/Manage ment). The permitting group is usually not firmly bound by the AALs; the AAL is just one of a number of factors to be considered in the permit process, which essentially is a risk management process (8). Another aspect of the air toxics issue is the implementation of SARA Title 313, which requires reporting of rou tine emissions (in pounds per year) to communities. What do these numbers mean in terms of human health? Risk communication is likely to be a major challenge for the industries and states, and it is likely that major differences of health 344l88e emissions. How this may then affect the derivation of AALs and the permitting process re mains to be seen. In summary, the EPA air toxics strat egy has led to the development of a highly decentralized approach for the regulation of air foxics at the state level. This in turn has led to the deriva tion of highly variable acceptable-expo sure guidelines for mutagens, carcino gens, teratogens, and systemic toxicants. Such interstate variability in AALs for toxic substances may lead to differential protection of the public health from air toxics, confuse the pub lic about air pollution and health con cerns, and undercut the credibility of public health and environmental regula tory agencies. It is interesting to note that while EPA encouraged the development of such divergence in air toxics regulatory approaches and implementation at the state level, the Food and Drug Admin istration funded a National Academy of Sciences (NAS) assessment of the fed eral process of risk assessment. The goal was to determine if greater con sistency could be achieved across agen- sions--especially those concerning the regulation of chronic health hazards. This effort resulted in the publication of the highly influential work, Risk As* sessment in the Federal Government: Managing the Process (II). Thus, while the NAS report ad dressed the lack of agreement in assess ing risk at the federal level and recom mended ways to minimize it, EPA was encouraging just the opposite with re spect to air toxics regulation at the state level. For example, the NAS commit tee strongly recommended "that uni form inference guidelines be developed for the use of federal regulatory agen cies in the risk assessment process" (12). Although there can be compelling reasons for different emission regula tions in different regions and states, EPA should strongly encourage the development of consistent risk assess ment methodologies that assist the risk manager in the final decision-making process. References 0) Calabrese, E. ). Methodologic Ap proaches to Deriving Environmental and Occupational Health Standards: Wiley: New York. 1978. TABLE 2 Highest and lowest ambient air levels (AALs) standardized to a 24-h averaging time by compound for representative known and probable human carcinogens, in nQlm3 * Compound Acrylonitrile Arsenic and compounds as As Benzene Eplchlorohydrln Ethylene dibromide Ethylene oxide Formaldehyde Nickel subsullide PCBs Vinyl chloride Original AAL 15 (NY) Standardized hlgheslAAL 257 0.67 (NY) 100 (NY Rl) 33.3 (NY) 1500 (VA) 450 (IN) 7.2 (Philadelphia) 24 (NV) 1.67 (NY) 6.57 (Philadelphia) 11.5 1718 572 1500 160 123.7 8.54 28.7 112.9 Original AAL 0.15 (MA) 0.0002 (Rl) 1.2 (MA) 2.7 (MA) 0.045 <NC) 0.01 (Rl) 0.77 (MA) 0,0017 (NC) 0.0081 (MA) 0.038 (NC) Standardized loweal AAL 0.15 0.0034 1.2 2.7 0.773 0.17 0.77 0.029 0.0081 0.65 Ratio standardized hloheatAoweat AAL 1713 3382 1432 212 1940 941 161 294 3543 174 'The original AALs and tneir averaging times were obtained from Reference 4 These substances are an classified in IARC groups 1 or 2A. AALs were standardized to 24-h averaging times for convenience based on Information provided in Reference 11. Annuel averaging times are In reality more appropriate for chronic endpoints such as carcinogenicity These figures are highest and lowest standardized AALs; other state and local agencies may have had higher or lower original AALs. When unstandardized highest and lowest AALs are compared, the differences are generally larger. TABLE 3 Highest and lowest ambient air levels (AALs) standardized to a 24-h averaging time by compound for representative noncarcinogens, in pQlm3 * Compound Acetone Ammonia Ethylene glycol Nhexane Napthalene Phenol Toluene Xylenes Original AAL 35.6 (NY) 0.36 (NY) 2.976 (NY) 30 (VA) 0.167 (NY) 0.456 (Philadelphia) 7.5 (Ntt 1.45 (NY) Standardized highest AAL 611.7 6.186 1.06 30 2.87 7.84 128.9 24.91 Original AAL 11.8 (CT, SO) 0.024 (MA) 0.17 (MA) 1.8 (NO) 0.014 (MA) 0.095 (IN) 0.051 (MA) 0.0592 MA Standardized lowest AAL 4.2 0.024 0.17 0.64 0.014 0.034 0.051 0.0592 Ratio standardized hlghest/lowest AAL 148 258 6.2 47 205 230 2527 421 'The original AALS and their averaging times were obtained from Reference 4. Units are standardized to 24 h for comparison, based on Information provided In Reference 11. These figures are highest and lowest standardized AALs; other state and local agencies may have had higher or lower original AALs. When unstandardized highest and lowest AALs are compared, the dlflerences are generally larger. Environ. Scl. Teehnol.. Vof. 23. No. 11,1989 1327