Air Pollutant Emission Inventory Development

Exponent’s air quality and meteorology (AQM) staff has experience and capabilities in a broad range of local-, urban-, regional-, and continental-scale air pollutant emission issues. These capabilities have evolved from our direct involvement in comprehensive state-of-science air dispersion model applications. Our scientists have an in-depth knowledge of air pollutant emission models and inventory development methods that encompass all regulated air pollutant species (both gaseous and particulate).

Clients benefit from our multidisciplinary approach, which includes the support of staff across multiple practice areas. Our atmospheric scientists work closely with chemical engineers, combustion specialists, and thermal and process engineers to estimate and evaluate air pollutant emissions.
Exponent scientists have developed emission inventories for a wide spectrum of air pollutant source types, including:

  • Industrial sources (such as refineries, smelters, power plants, pulp and paper mills, mines, pipelines, product storage, and manufacturing facilities)
  • Airports, seaports, mobile sources (cars, trucks, trains, aircraft, ships, barges, non-road vehicles)
  • Agricultural activities (spaying, fumigation, tilling, harvesting, and field burning)
  • Fugitive dust emissions, including time-varying emissions
  • Volatile emissions from chemical spills
  • Wild- and forest-fires, structural fires, explosions, radioactive material releases, spills, fugitive releases
  • Natural sources (biogenic, geogenic, seawater), and odors.

Our team has also developed gridded urban and regional emission inventories, including those required to support photochemical modeling. These inventories have often been used to evaluate non-linear interactions between emissions of nitrogen oxides and volatile organic compounds and their contributions to ozone, NO2, and secondary fine particulates formation. We have prepared gridded inventories for more than 20 U.S. metropolitan cities, and an equal number of foreign urban centers. We have also developed emission inventories for modeling long-range air pollution transport between U.S. urban centers and across international borders.

Exponent also has extensive experience obtaining and working with emissions inventory data from publicly available data bases, including the national emissions inventory (NEI), Toxics Release Inventory (TRI), Greenhouse Gas Reporting Program (GHGRP), Emission Database for Global Atmospheric Research (EDGAR), U.S. Environmental Protection Agency (EPA) air markets program data (AMPD), emissions & generation resource integrated database (eGRID), Regional Greenhouse Gas Initiative (RGGI) CO2 Allowance Tracking System (COATS), United Nations Environmental Programme (UNEP) greenhouse gas databases, U.S. Inventory of Greenhouse Gas Sources and Sinks, and various other state and regional emission inventories.

Example Projects

Exponent compiled a comprehensive emission inventory for a large steel mill and conducted modeling to estimate potential impacts of particulate and dioxin emissions. Results were incorporated in human and ecological risk assessment analyses.

Exponent compiled an inventory of fugitive dust emissions sources, including wind erosion, material handling, and the re-entrainment of material on paved and unpaved roads, to use in modeling analyses conducted to respond to claims of harm in a litigation matter. The inventory accounted for meteorological conditions, including wind speed and precipitation. Particle size distributions were accounted for based on field data, laboratory analysis, and information in the scientific literature.

Exponent compiled a detailed source emissions inventory including emissions from mobile sources, such as on-road motor vehicles, non-road vehicles, marine vessels, and locomotives to help evaluate various scenarios involving alternative fuel and emissions control options.