Modeling of Ammonia and PM2.5 Concentrations Associated with Emissions from Agriculture

Megan Gore, D.Q. Tong, V.P. Aneja, and M. HouyouxDepartment of Marine, Earth & Atmospheric SciencesNorth Carolina State UniversityRaleigh, NC 27695

7th Annual CMAS Conference October 6-8, 2008

Outline

٥ Introduction – Ammonia in North Carolina (NC)

٥ Model Configuration

٥ Preliminary Results

٥O3, NH3, PM2.5, NH4+

٥ Conclusions

٥ Future Work

NH3

Why do we care about Ammonia?

Elevated levels of NHx (=NH3 + NH4+) can

lead to:

٥Nitrogen enrichment and eutrophication in aquatic ecosystems

٥ Impacts on crop and forest production

٥Particulate matter (PM) formation

٥Visibility degradation

٥Odor

Nitrogen Emissions in N.C.NH3 Agricultural Sources

Total ~ 40% of Nitrogen

138,843 NH3 tons/yr

• Swine 68,540 (49%)

• Cattle 24,952 (18%)

• Broilers 13,669 (10%)

• Turkeys 16,486 (12%)

• Fertilizer 8,720 (6%)

• Other 6,476 (5%)

(Aneja et al., 1998)

Hog Farms in N.C.

Ammonia Atmospheric Chemistry

Atmospheric Reactions:

٥ NH3(aq) + H20 NH4OH(aq)

٥ NH3(g) + H2SO4(aq) NH4HSO4(aq)

٥ NH3(g) + NH4HSO4(aq) [NH4]2SO4(s or aq)

٥ NH3(g) + HNO3(g) NH4NO3(s or aq)

٥ NH3(g) + HCl(g) NH4Cl(s or aq)

٥ NH3(g) + OH·(g) N·H2(g) + H2O(g)

Model Configuration

٥ Model: Community Multi-Scale Air Quality (CMAQ) Model

٥ Episode: January 1 – December 31, 2002

٥ Domain: Continental U.S., N. Mexico, S. Canada36 km, 24 layers

٥ Meteorology: MM5 - Pleim-Xiu Land Surface module on

٥ Emissions: 2002 National Emissions Inventory

٥ I/B Conditions: MOZART-2 for lateral BC

٥ Gas-phase mechanism: Carbon Bond (CB05)

٥ Aerosol module: AE4

Preliminary Results Ozone

space

January Base Run – Ozone

Monthly Average

January Reduced Run* – Ozone

Monthly Average

*Reduced Run – NH3 Emissions turned off

ppbv

Preliminary Results Ozone

July Base Run – Ozone

Monthly Average

July Reduced Run* – Ozone

Monthly Average

*Reduced Run – NH3 Emissions turned off

ppbv

Preliminary Results – NH3

January Base Run – NH3

Monthly Average

January Reduced Run* – NH3

Monthly Average

*Reduced Run – NH3 Emissions turned off

ppbv

Preliminary Results – NH3

July Base Run – NH3

Monthly Average

July Reduced Run* – NH3

Monthly Average

*Reduced Run – NH3 Emissions turned off

ppbv

Preliminary Results PM2.5

January Base Run – PM2.5

Monthly Average

January Reduced Run* – PM2.5

Monthly Average

*Reduced Run – NH3 Emissions turned off

Preliminary Results PM2.5

Base Run – January 2002, NC

Monthly Average

Preliminary Results PM2.5

Reduced Run – January 2002, NC

Monthly Average

Preliminary Results PM2.5

July Base Run – PM2.5

Monthly Average

July Reduced Run* – PM2.5

Monthly Average

*Reduced Run – NH3 Emissions turned off

Preliminary Results PM2.5

Base Run – July 2002, NC

Monthly Average

Preliminary Results PM2.5

Reduced Run – July 2002, NC

Monthly Average

Preliminary Results–NH4+ Aerosol

January Base Run – NH4+

Monthly Average

January Reduced Run – NH4+

Monthly Average

*Reduced Run – NH3 Emissions turned off

Preliminary Results–NH4+ Aerosol

July Base Run – NH4+

Monthly Average

July Reduced Run – NH4+

Monthly Average

*Reduced Run – NH3 Emissions turned off

Conclusions

٥ Agricultural NH3 emissions have a significant impact on PM2.5 and NH4 aerosol predicted concentrations

Future Work

Additional model runs turning off emissions from the various agricultural sectors

Evaluate the effect of ammonia emissions of aerosol composition

Model evaluation using observed values of pollutants

Meteorological analysis

Acknowledgements

٥ USDA

٥ USEPA

٥ NCSU Air Quality Research Group

Atmospheric emissions, transport,transformation & deposition of trace gases

*Indirect deposition is direct deposition to land followed by runoff or seepage through groundwater to a surface water body.

Preliminary Results Ozone

Base Run – January 2002, NC

Monthly Average

ppbv

Preliminary Results Ozone

Reduced Run – January 2002, NC

Monthly Average

ppbv

Preliminary Results Ozone

Difference Between Base Run and Reduced Run

January 2002, NC - Monthly Average

ppbv

Preliminary Results Ozone

Base Run – July 2002, NC

Monthly Average

ppbv

Preliminary Results Ozone

Reduced Run – July 2002, NC

Monthly Average

Preliminary Results Ozone

Difference Between Base Run and Reduced Run

January 2002, NC - Monthly Average

ppbv

Preliminary Results – NH3

Base Run – January 2002, NC

Monthly Average

ppbv

Preliminary Results – NH3

Reduced Run – January 2002, NC

Monthly Average

Preliminary Results – NH3

Difference Between Base Run and Reduced Run

January 2002, NC - Monthly Average

ppbv

Preliminary Results – NH3

Base Run – July 2002, NC

Monthly Average

ppbv

Preliminary Results – NH3

Reduced Run – July 2002, NC

Monthly Average

Preliminary Results – NH3

Difference Between Base Run and Reduced Run

July 2002, NC - Monthly Average

ppbv

Preliminary Results PM2.5

Difference Between Base Run and Reduced Run

January 2002, NC - Monthly Average

Preliminary Results PM2.5

Difference Between Base Run and Reduced Run

July 2002, NC - Monthly Average

Preliminary Results–NH4+ Aerosol

Base Run – January 2002, NC

Monthly Average

Preliminary Results–NH4+ Aerosol

Reduced Run – January 2002, NC

Monthly Average

Preliminary Results–NH4+ Aerosol

Difference Between Base Run and Reduced Run

January 2002, NC - Monthly Average

Preliminary Results–NH4+ Aerosol

Base Run – July 2002, NC

Monthly Average

Preliminary Results–NH4+ Aerosol

Reduced Run – July 2002, NC

Monthly Average

Preliminary Results–NH4+ Aerosol

Difference Between Base Run and Reduced Run

July 2002, NC - Monthly Average