Spatially Explicit Modeling of Criteria Air 

Pollutants from Agricultural and Forestry 

Feedstock Production

Rebecca Hanes, Yimin Zhang, Daniel Inman, Annika Eberle, 

Garvin Heath and Dylan Hettinger

Strategic Energy Analysis Center

National Renewable Energy Laboratory, Golden, Colorado

ICOSSE 2018

August 12-15, 2018

This work was authored by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-

08GO28308. Funding provided by U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Bioenergy Technologies Office. The views expressed in the article do not 

necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. 

Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes.
NREL | 2

Background: FPEAM 1.0

• Feedstock Production Emissions to Air Model

• Python codebase initially developed in 2014, revised and 

expanded for the 2016 update to DOE’s Billion Ton Report 

– Calculate spatially explicit, county-scale inventories of air 

pollutants produced during biomass feedstock production, 

harvest and transportation 

– Identify counties where biomass production could put 

counties out of 2015 National Ambient Air Quality Standards 

attainment

• Public release planned since 2017, following extensive 

refactoring to increase utility to air pollutant analysts

Efroymson RA, et al. (2017)
NREL | 3

Use Cases

Basic

• Assess change in pollutant type, quantity and location 

associated with increase in feedstock production or change 

in feedstock type

User-customized spatial scale

• Calculate inventories by congressional district, farm or other 

stakeholder-relevant regions

Calculate inputs to other models

• Use FPEAM to generate pollutant inventories for inputs into 

air quality models
NREL | 4

Objectives

• Data-driven model structure to ensure flexibility and user control 

over scenarios

– Model any feedstock, any farming practice, any spatial scale

– Analysis capabilities limited by input data availability rather 

than model structure

• Build code base to make future expansions, updates easy to 

implement

– Reduce effort for continued improvement by developers and 

by users

FPEAM Release Target Date

Limited beta September 2018

Public September 2019
NREL | 

5

• Codebase consists of five semi-

independent calculation modules

• Outputs include raw pollutant 

inventory and basic visualizations

FPEAM 2.0

Model Structure

Module Pollutant Calculation

MOVES

Feedstock transportation Routing

NONROAD On-farm equipment use

Fugitive Dust On-farm dust generated

Emissions 

Factors

On-farm chemical application;

any factor-based calculation 
NREL | 6

Input Data

MOVES

NONROAD

Emissions 

Factors

Fugitive Dust

Routing

Feedstock production 

(where, what, how much)

Agricultural equipment 

and resource use

Transportation vehicle 

parameters 

Fugitive dust factors by 

feedstock type

Emissions factors by 

resource and pollutant

FPEAM Modules Output

Air Pollutant 

Inventory

• Pollutants by 

feedstock, 

region, farming 

practice and 

activity
NREL | 7

• Motor Vehicle Emission Simulator, developed by U.S. EPA, is 

an emissions modeling system that simulates mobile criteria 

and other pollutant sources at various spatial scales

• Output: Emissions factors that are postprocessed with 

routing information to yield total pollutant inventories by 

feedstock and region

MOVES

CO, VOC, PM10, PM2.5, NOx, SOx, NH3,

other pollutants

feedstock tillage region_production region_destination measure amount unit

switchgrass no tillage 40025 31067 harvested 28888.0 acre

switchgrass no tillage 40025 31067 production 91284.3 dry short ton

switchgrass no tillage 40025 31067 planted 29014.6 acre

switchgrass no tillage 40025 31067 yield 3.1 dry short ton/acre

Default data source: See Zhang et al. (2015)
NREL | 8

Routing

Combined with MOVES-calculated emissions factors

• Input data specifies feedstock 

production regions and 

destinations

– Depot or biorefinery 

location

• Routing module finds shortest 

path between region centroids 

via major roads 

• Output: transportation 

emissions in every region 

along calculated route

Sample route from Cherokee 

County, NC to Jefferson County, CO

Global Roads Open Access Data Sets (gROADS) v1
NREL | 9

• Emissions simulator developed by U.S. EPA for off-road 

mobile sources, packaged with MOVES2014b

• Output: pollutant inventories for on-farm agricultural 

equipment use

NONROAD

CO, VOC, PM10, PM2.5, NOx, SOx, NH3,

other pollutants

feedstock tillage activity equipment resource rate unit

biomass 

sorghum 

reduced 

tillage establishment tractor 2wd 

135 hp time 0.09 hour/acre

biomass 

sorghum

reduced 

tillage harvest

forage 

harvester (6 

row head)

time 0.96 hour/acre

biomass 

sorghum

reduced 

tillage maintenance tractor 2wd 55 

hp time 0.04 hour/acre

Default data source: See Zhang et al. (2015)
NREL | 10

Emissions Factors

VOC, NOx, NH3,

other pollutants optional

• Default: NOx and NH3 from 

nitrogen fertilizer; VOC from 

herbicide, insecticide

• Calculation can be extended to 

any number of pollutants and 

activities with sufficient input data

• Potential for replacing MOVES 

and/or NONROAD, but tradeoff 

exists between model run time 

and accuracy

Fugitive Dust

PM10, PM2.5

• Default: PM10 and PM2.5 emissions 

from agricultural equipment use 

and tilling operations

Default data source: Zhang et al. (2015) Default data source: California Air Resources 

Board, Midwest Research Institute

Resource rate

Resource 

subtype

(optional)

Emissions 

factor(s)

Pollutant 

amount
NREL | 11

Sample Pollutant 

Inventory Visualizations

Emissions variability by county

PM10 NAA Status

Counties in Attainment

Whole or Partial Non-Attainment

Efroymson RA, et al. (2017)
NREL | 12

Continuing Development

• Assess the human health impacts of criteria air 

pollutant inventories

• Calculate fugitive dust from feedstock transportation 

using road-surface data and routing info

• Adjust path-finding algorithm used in routing to favor 

interstates, circumvent population centers and use 

multiple modes of transportation

• Expand calculations to include economic impacts such 

as jobs created by region and whether those jobs are 

seasonal or year-round
NREL | 13

Conclusion

• FPEAM calculates spatially explicit inventories of air 

pollutants produced during biomass feedstock production, 

harvest and transportation

• Modeling capabilities are flexible, limited primarily by input 

data availability

• Use cases include identification of criteria air pollutant hot 

spots, air quality modeling (in progress), and inventory 

analyses at the farm or congressional district scale

FPEAM Release Target Date

Limited beta September 2018

Public September 2019
www.nrel.gov

Thank you

NREL/PR-6A20-72126

Workshop for FPEAM beta testers

• September 20-21, 2018

• Held on NREL campus

• Interested? Contact Garvin 

Heath at garvin.heath@nrel.gov 

and Melissa Hudman at 

melissa.hudman@nrel.gov

Further information and questions,

contact rebecca.hanes@nrel.gov