MNRISKS and AERA

Tools to model disease risk from pollutant exposure

MNRISKS

History

MNRISKS began as a collaboration between the US EPA and the MN Pollution Control Agency (MPCA) in the early 2000s.

  • The initial version of MNRISKS was based on 1999 emissions data
  • Updated with new emissions and sources every 3 years when the EPA’s latest emission inventory is updated
    • NOTE: The 2023 National Emissions Inventory is still not available on the EPA’s site (as of March 10, 2025).

Sources of pollution

  1. Point sources (e.g. Permitted facilities)
  2. Non-point sources (e.g. backyard fires, residential heating)
  3. Onroad mobile sources (e.g. Cars, Trucks, Heavy duty vehicles)
  4. Non-road mobile sources (e.g. ATVs, boats, construction equipment)

Note: there seem to be different graphics for point, non-point, other sources of pollution for water vs air. When searching, I initially primarily found graphics related to water pollution.

AERA (Air Emissions Risk Analysis)

Resources

Notes

Form aq9-22 is the air emissions risk assessment screening spreadsheet (RASS). Available here

Looking at the cell formulas in the “Risk Calcs” sheet tells us how health risks were calculated. The risk calculations

Inhalation Risks

  • Acute: Acute Air Concentration (Tox Values cell G6)
  • Subchronic Noncancer: Sub-Chronic Air Concentration (Tox Values cell AA6)
    • “Subchronic toxicity refers to the damage of body function and/or structure caused by short exposure period (generally 3 months) or short exposure time (several days to months).” Source
  • Chronic Noncancer: Non-Cancer Chronic Air Concentration (Tox Values cell T6)
  • Cancer Index: Cancer Based Air Concentration (Risk of 1E-05) (Tox Values cell O6)

If the associated Air Concentration from the Tox Values sheet is non-missing and if the pollutant is actually emitted, risk from this pollutant is calculated as: Pollutant Concentration / Air Concentration. This is a ratio measure: How many fold higher/lower is this pollutant than the reference air concentration?

Chronic Non-inhalation Pathway Risks = Scaled versions of the quantities in Inhalation Risks based on exposure multipliers for farmers, urban gardeners, and residents

Chronic Total Risks (Inhalation + Non-inhalation) = Sum of previous group (Chronic Non-inhalation Pathway Risks) and an Inhalation Risk

All of these above risks are summed over pollutants. Pollutants with missing inhalation health benchmarks are treated as zeros.