NAAQS Altitude Effects

Ozone Transport Commission Annual Meeting

June 11, 2014Baltimore, MD

Will Ollison

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org

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Compliance with PM NAAQSPM2.5/10 compliance addresses altitude effects.•40 CFR Part 50, Appendix L, Section 2.2: Each filter is weighed…before and after sample collection to determine the net gain due to collected PM2.5. The total volume of air sampled is determined by the sampler from the measured flow rate at actual ambient temperature and pressure and the sampling time. The mass concentration of PM2.5 in the ambient air is computed as the total mass of collected particles in the PM2.5 size range divided by the actual volume of air sampled, and is expressed in micrograms per cubic meter of air.

•40 CFR Part 50, Appendix J, Section 2.2: …For PM10 samples collected at temperatures and pressures significantly different from EPA reference [25°C, 1 atm] conditions, these corrected concentrations sometimes differ substantially from actual concentrations,…particularly at high elevations. Although not required, the actual PM10 concentration can be calculated from the corrected concentration, using the average ambient temperature and barometric pressure during the sampling period.

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org2

Compliance with O3 NAAQSO3 compliance does not address altitude effects.•40 CFR Part 50 Appendix P, Section 2.2: The standard-related summary statistic is the annual fourth-highest daily maximum 8-hour O3 concentration, expressed in parts per million, averaged over three years. The 3-year average shall be computed using the three most recent, consecutive calendar years of monitoring data meeting the data completeness requirements described in this appendix. The computed 3-year average of the annual fourth-highest daily maximum 8-hour average O3 concentrations shall be reported to three decimal places (the digits to the right of the third decimal place are truncated, consistent with the data handling procedures for the reported data).

•O3 photometers calculate and report parts per million mixing ratios from measured actual concentrations at absorption tube temperatures and pressures. These mixing ratio O3 compliance metrics are pressure invariant and do not change with altitude.

•At a given O3 ppm level and breathing rate less O3 mass is inhaled at higher altitudes, penalizing highlanders into complying with lower effective NAAQS than lowlanders.

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org

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OTC State 2010-2012 Design Values - Monitors > 1000 feet

State Height (feet) < 75 ppb < 70 ppb < 65 ppb < 60 ppb Monitor

Alt Adj < 75 ppb

Alt Adj < 70 ppb

Alt Adj < 65 ppb

Alt Adj < 60 ppb

CT 1519 YES NO NO NO 090050005 YES YES NO NOME 1507 230090102 MD 2356 240230002 MA 3482 250034002 MA 1006 250154002 NH 6233 330074001 NH 1386 330074002 NH 2286 330115001 NY 1063 360130011 NY 1939 360310003 NY 1693 360410005 NY 1764 360430005 NY 1534 360830004 NY 1603 361010003 NY 1941 361111005 VT 1325 500070007 VA 3526 511130003 VA 1106 511611004 VA 1282 511650003 VA 2466 511970002

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org

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OTC State 2010-2012 Design Values - Monitors > 1000 feet

State Height (feet) < 75 ppb < 70 ppb < 65 ppb < 60 ppb Monitor

Alt Adj < 75 ppb

Alt Adj < 70 ppb

Alt Adj < 65 ppb

Alt Adj < 60 ppb

PA 1261 NO NO NO NO 420030067 YES NO NO NOPA 1145         420050001        

PA 1334         420070002        

PA 1216         420070005        

PA 1132         420130801        

PA 1174         420210011        

PA 1168         420270100        

PA 2129         420334000        

PA 2018         420550001        

PA 1403         420590002        

PA 1900         420630004        

PA 1095         420850100        

PA 1301         420890002        

PA 2244         421174000        

PA 1158         421250200        

PA 1126         421255001        

PA 1188         421290008        

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org

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Recommendations• Since EPA will use high elevation rural/remote CASTNet O3 monitor design values for 2011-

2013 NAAQS compliance determinations, and

• Since CASAC will recommend EPA reduce the 75 ppb O3 NAAQS into the 60-70 ppb mixing ratio range, and

• Since CASAC-AMMS will recommend a new interference-free O3 Federal Reference Method,

• OTC States should (1) request that EPA expedite upgrades of existing OTC network O3 monitors to interference-free status and (2) account for altitude effects in any revised mixing ratio O3 NAAQS.

• Request that EPA to account for altitude effects in gaseous NAAQS

1220 L Street, NW • Washington, DC 20005-4070 • www.api.org

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