OAR 340-246-0090
Ambient Benchmarks for Air Toxics
(1)
Purpose. Ambient benchmarks are concentrations of air toxics that serve as goals in the Oregon Air Toxics Program. They are based on human health risk and hazard levels considering sensitive populations. Ambient benchmarks are not regulatory standards, but reference values by which air toxics problems can be identified, addressed and evaluated. DEQ will use ambient benchmarks as indicated in these rules, to implement the Geographic, Source Category, and Safety Net Programs. Ambient benchmarks set by the procedures described in this rule apply throughout Oregon, including that area within the jurisdiction of the Lane Regional Air Protection Agency. In OAR 340-245-0300 (Toxicity Reference Values), ambient benchmarks may also be considered in the risk-based concentration hierarchy used to determine risk-based concentrations for purposes of Cleaner Air Oregon regulations in OAR 340-245-0005 (Purpose and Overview) through 240-245-8050. Ambient benchmarks are subject to public notice and comment before adoption by the Environmental Quality Commission as administrative rules.(2)
Establishing Ambient Benchmarks(a)
DEQ will consult with the ATSAC to prioritize air toxics for ambient benchmark development. Highest priority air toxics are those that pose the greatest risk to public health.(b)
To prioritize air toxics, DEQ will apply the criteria described in OAR 340-246-0090 (Ambient Benchmarks for Air Toxics)(2)(c) to modeling, monitoring, and emissions inventory data.(c)
Ambient benchmark prioritization criteria will include at least the following:(A)
Toxicity or potency of a pollutant;(B)
Exposure and number of people at risk;(C)
Impact on sensitive human populations;(D)
The number and degree of predicted ambient benchmark exceedances; and(E)
Potential to cause harm through persistence and bio-accumulation.(d)
DEQ will develop ambient benchmarks for proposal to the ATSAC based upon a protocol that uses reasonable estimates of plausible upper-bound exposures that neither grossly underestimate nor grossly overestimate risks.(e)
Within three months of the first meeting of the ATSAC, DEQ will propose ambient benchmark concentrations for the highest priority air toxics for review by the ATSAC. DEQ will propose additional and revised air toxics ambient benchmarks for review by the ATSAC based on the prioritization criteria in OAR 340-246-0090 (Ambient Benchmarks for Air Toxics)(2)(c). Once the ATSAC has completed review of each set of proposed ambient benchmarks, DEQ will, within 60 days, begin the process to propose ambient benchmarks as administrative rules for adoption by the Environmental Quality Commission.(f)
If DEQ is unable to propose ambient benchmarks to the ATSAC by the deadlines specified in OAR 340-246-0090 (Ambient Benchmarks for Air Toxics)(2)(e), the ATSAC will review the most current EPA ambient benchmarks. If EPA ambient benchmarks are not available, the ATSAC will review the best available information from other states and local air authorities.(g)
The ATSAC will consider proposed ambient benchmarks and evaluate their adequacy for meeting risk and hazard levels, considering human health, including sensitive human populations, scientific uncertainties, persistence, bio-accumulation, and, to the extent possible, multiple exposure pathways. The ATSAC will conduct this review consistent with the criteria in OAR 340-246-0090 (Ambient Benchmarks for Air Toxics)(2)(c) and (d). The ATSAC will report these findings to DEQ. If the ATSAC unanimously disagrees with DEQ’s recommendation, DEQ will re-consider and re-submit its recommendation at a later date.(h)
The ATSAC will complete review of and report findings on each set of ambient benchmarks as quickly as possible, but no later than 12 months after DEQ has proposed them. If the ATSAC is unable to complete review of ambient benchmarks within 12 months after DEQ’s proposal, DEQ will initiate rulemaking to propose ambient benchmarks.(i)
DEQ will review all ambient benchmarks at least every five years and, if necessary, propose revised or additional ambient benchmarks to the ATSAC. At its discretion, DEQ may review and propose a benchmark for review by the ATSAC at any time when new information is available.(3)
Ambient Benchmarks. Benchmark concentrations are in units of micrograms of air toxic per cubic meter of ambient air, on an average annual basis. The Chemical Abstract Service Registry Number (CASRN) is shown in parentheses.(a)
The ambient benchmark for acetaldehyde (75-07-0) is 0.45 micrograms per cubic meter.(b)
The ambient benchmark for acrolein (107-02-8) is 0.35 micrograms per cubic meter.(c)
The ambient benchmark for acrylonitrile (107-13-1) is 0.01 micrograms per cubic meter.(d)
The ambient benchmark for ammonia (7664-41-7) is 500 micrograms per cubic meter.(e)
The ambient benchmark for arsenic (7440-38-2) is 0.0002 micrograms per cubic meter.(f)
The ambient benchmark for benzene (71-43-2) is 0.13 micrograms per cubic meter.(g)
The ambient benchmark for beryllium (7440-41-7) is 0.0004 micrograms per cubic meter.(h)
The ambient benchmark for 1,3-butadiene (106-99-0) is 0.03 micrograms per cubic meter.(i)
The ambient benchmark for cadmium and cadmium compounds (7440-43-9) is 0.0006 micrograms per cubic meter.(j)
The ambient benchmark for carbon disulfide (75-15-0) is 800 micrograms per cubic meter.(k)
The ambient benchmark for carbon tetrachloride (56-23-5) is 0.2 micrograms per cubic meter.(l)
The ambient benchmark for chlorine (7782-50-5) is 0.1 micrograms per cubic meter.(m)
The ambient benchmark for chloroform (67-66-3) is 300 micrograms per cubic meter.(n)
The ambient benchmark for chromium, hexavalent (18540-29-9) is 0.00008 micrograms per cubic meter.(o)
The ambient benchmark for cobalt and cobalt compounds (7440-48-4) is 0.1 micrograms per cubic meter.(p)
The ambient benchmark for 1,4-dichlorobenzene (106-46-7) is 0.09 micrograms per cubic meter.(q)
The ambient benchmark for 1,3-dichloropropene (542-75-6) is 0.25 micrograms per cubic meter.(r)
The ambient benchmark for diesel particulate matter (none) is 0.1 micrograms per cubic meter. The benchmark for diesel particulate matter applies only to such material from diesel-fueled internal combustion sources.(s)
The ambient benchmark for dioxins and furans (1746-01-6) is 0.00000003 micrograms per cubic meter. The benchmark for dioxin is for total chlorinated dioxins and furans expressed as 2,3,7,8-TCDD toxicity equivalents.(t)
The ambient benchmark for ethyl benzene (100-41-4) is 0.4 micrograms per cubic meter.(u)
The ambient benchmark for ethylene dibromide (106-93-4) is 0.002 micrograms per cubic meter.(v)
The ambient benchmark for ethylene dichloride (107-06-2) is 0.04 micrograms per cubic meter.(w)
The ambient benchmark for ethylene oxide (75-21-8) is 0.0003 micrograms per cubic meter.(x)
The ambient benchmark for formaldehyde (50-00-0) is 0.2 micrograms per cubic meter.(y)
The ambient benchmark for n-hexane (110-54-3) is 700 micrograms per cubic meter.(z)
The ambient benchmark for hydrogen chloride (7647-01-0) is 20 micrograms per cubic meter.(aa)
The ambient benchmark for hydrogen cyanide (74-90-8) is 0.8 micrograms per cubic meter.(bb)
The ambient benchmark for fluoride anion (7664-39-3) is 13 micrograms per cubic meter.(cc)
The ambient benchmark for lead and lead compounds (7439-92-1) is 0.15 micrograms per cubic meter.(dd)
The ambient benchmark for manganese and manganese compounds (7439-96-5) is 0.09 micrograms per cubic meter.(ee)
The ambient benchmark for elemental mercury (7439-97-6) is 0.3 micrograms per cubic meter.(ff)
The ambient benchmark for methyl bromide (74-83-9) is 5 micrograms per cubic meter.(gg)
The ambient benchmark for methyl chloride (74-87-3) is 90 micrograms per cubic meter.(hh)
The ambient benchmark for methyl chloroform (71-55-6) is 5,000 micrograms per cubic meter.(ii)
The ambient benchmark for methylene chloride (75-09-2) is 100 micrograms per cubic meter.(jj)
The ambient benchmark for naphthalene (91-20-3) is 0.03 micrograms per cubic meter.(kk)
The benchmark for soluble nickel compounds (various) is 0.01 micrograms per cubic meter, where soluble nickel compounds include nickel acetate (373-20-4), nickel chloride (7718-54-9), nickel carbonate (3333-39-3), nickel carbonyl (13463-39-3), nickel hydroxide (12054-48-7), nickelocene 1271-28-9), nickel sulfate 7786-81-4), nickel sulfate hexahydrate 10101-97-0), nickel nitrate hexahydrate (13478-00-7), and nickel carbonate hydroxide (12607-70-4).(ll)
The ambient benchmark for insoluble nickel compounds (various) is 0.004 micrograms per cubic meter, where insoluble nickel compounds include nickel subsulfide (12035-72-2), nickel oxide (1313-99-1), nickel sulfide (11113-75-0), and nickel metal (7440-02-0).(mm)
The ambient benchmark for phosphine (7803-51-2) is 0.8 micrograms per cubic meter.(nn)
The ambient benchmark for phosphoric acid (7664-38-2) is 10 micrograms per cubic meter.(oo)
The ambient benchmark for total (as the sum of congeners) polychlorinated biphenyls (1336-36-3) is 0.01 micrograms per cubic meter.(pp)
The ambient benchmark for total polycyclic aromatic hydrocarbons (none) is 0.002 micrograms per cubic meter, where total polycyclic aromatic hydrocarbons are the sum of the toxicity equivalency factor (with respect to benzo(a)pyrene (50-32-8)) adjusted concentrations for all of the following individual 26 polycyclic aromatic hydrocarbons: 5-methylchrysene (3697-24-3); 6-nitrochrysene (7496-02-8); acenaphthene (83-32-9); acenaphthylene (208-96-8); anthanthrene (191-26-4); anthracene (120-12-7); benz(a)anthracene (56-55-3); benzo(a)pyrene (50-32-8); benzo(b)fluoranthene (205-99-6); benzo(c)fluoranthene (243-17-4); benzo(e)pyrene (192-97-2); benzo(g,h,i)perylene (191-24-2); benzo(j)fluoranthene ( 205-82-3); benzo(k)fluoranthene (207-08-9); chrysene (218-01-9); cyclopenta(c,d)pyrene (27208-37-3); dibenz(a,h)anthracene (226-36-8); dibenzo(a,e)pyrene (192-65-4); dibenzo(a,h)pyrene (189-64-0); dibenzo(a,i)pyrene (189-55-9); dibenzo(a,l)pyrene (191-30-0); fluoranthene (206-44-0); fluorene (86-73-7); indeno(1,2,3-c,d)pyrene (193-39-5); phenanthrene (85-01-8); and pyrene (129-00-0).(qq)
The ambient benchmark for tetrachloroethylene (127-18-4) is 4 micrograms per cubic meter.(rr)
The ambient benchmark for toluene (108-88-3) is 5,000 micrograms per cubic meter.(ss)
The ambient benchmark for 2,4- & 2,6 toluene diisocyanate, mixture (26471-62-5) is 0.02 micrograms per cubic meter.(tt)
The ambient benchmark for trichloroethylene (79-01-6) is 0.2 micrograms per cubic meter.(uu)
The ambient benchmark for vinyl chloride (75-01-4) is 0.1 micrograms per cubic meter.(vv)
The ambient benchmark for white phosphorus (7723-14-0) is 9 micrograms per cubic meter.(ww)
The ambient benchmark for xylenes, mixed (1330-20-7) is 200 micrograms per cubic meter.(xx)
The ambient benchmark for hydrogen sulfide (7783-06-4) is 2.0 micrograms per cubic meter.(yy)
The ambient benchmark for methanol (67-56-1) is 4,000 micrograms per cubic meter.(zz)
The ambient benchmark for phosgene (75-44-5) is 0.3 micrograms per cubic meter.(aaa)
The ambient benchmark for n-propyl bromide (106-94-5) is 0.5 micrograms per cubic meter.(bbb)
The ambient benchmark concentration for styrene (100-42-5) is 1,000 micrograms per cubic meter.
Source:
Rule 340-246-0090 — Ambient Benchmarks for Air Toxics, https://secure.sos.state.or.us/oard/view.action?ruleNumber=340-246-0090.