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
NO2
HCHO/NO2
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 > 1Suggests NOx limited
(Duncan et al., 2010)
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 hr avrg) 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