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Ozone and nitrogen deposition from Colorado’s Craig powerstation. NOx from Craig. The Craig powerstation is the largest uncontrolled NOx source in the state (~18k tons/ yr ) NPS is lobbying EPA for stricter controls (i.e., SCR on all three boilers) What is the impact in terms of . Ozone
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Ozone and nitrogen deposition from Colorado’s Craig powerstation
NOx from Craig • The Craig powerstation is the largest uncontrolled NOx source in the state (~18k tons/yr) • NPS is lobbying EPA for stricter controls (i.e., SCR on all three boilers) • What is the impact in terms of • Ozone • Nitrogen dep • PM nitrate
Approach • Reduce NO and NO2 emissions from Craig w.r.t. three proposed scenarios • NPS option is most stringent with full SCR • Reduce NOx from ~18k tons/yr to ~3k tons/yr • Run CAMx for a year (2005) with 12km 4CAQTF inputs
VOC vs. NOx from OMI HCHO and NO2 can be detected from the OMI satellite, and provide ‘indicator species’ to help assess whether a region is VOC or NOx limited. HCHO/NO2 > 1 Suggests NOx limited (Duncan et al., 2010) HCHO NO2 HCHO/NO2 Craig
Summary • Given VOC/NOx ratios in northwestern CO, NOx controls should be effective for reducing ozone, N dep, and haze • NOx emissions from O&G development in the region (Uintah, Piceance, and SW Wyo) are also a concern • Emissions at the surface: shorter transport? • This sector is growing, and NOx controls may be harder to apply
Summary (cont’d) • The benefits from full SCR at Craig could be significant: • Ozone: • 2 – 6 ppb (8 hravrg) ozone reduction at Flat Tops WA • 1 – 2 ppb at ROMO • N dep: • 0.2 kg N/ha/yr reduction at Mt Zirkel • 0.14 kg N/ha/yr reduction at ROMO • PM nitrate: • 0.6 ug/m3 reduction at ROMO
Summary (cont’d) • Nitrate behavior seems a little strange • N dep at ROMO was ~linear w.r.t. to reductions • Next time should use plume-in-grid to better capture high NOx chemistry