# Presentation: 686785

## Risk Screening of Point Source Air Toxics in Minneapolis/St. Paul, Minnesota

- Michele Knox Palmer
- Environmental Engineer
- Integrated Air Toxics Section
- EPA Region V, Chicago, IL
- April 8, 2008

## Outline

- Background on Air Toxics Program
- Risk Screening Process and Tools
- Minneapolis/St. Paul Case Study
- Risk Screening
- Monitoring Data
- Conclusions
- On-line Resources

**Notes:**
These tools are publicly available and I will share how to access them at the end of my presentation

## What are Air Toxics?

- 187 Hazardous Air Pollutants identified in the Clean Air Act 112(b)
- Many are known or suspected carcinogens
- May cause damage to
- respiratory, reproductive, immunological
- neurological or hormonal systems
- Examples include benzene, metals, dioxins

**Notes:**
Although this is not all the air toxics
Many are being discovered and created everyday
Others may damage various organ systems

## What are Sources of Air Toxics?

- Point Sources
- Large and small Industries
- Area Sources
- Gas stations and dry cleaners
- Mobile Sources
- Cars, boats, planes and trucks
- Natural Sources
- Wildfires and volcanoes

**Notes:**
This specific project deals with point sources

## What are US EPA’s Air Toxics Program Goals?

- Further understand and characterize human health risks
- Reduce human health risks due to exposure to air toxics
- Utilize a combination of
- technology-based standards
- risk-based programs
- voluntary reduction initiatives

**Notes:**
The science of health risk assessments is still being developed and refined
We intend to achieve our goals through a combination of . . .
Techn – the best we can achieve with available techn

## What are Region V’s Regional Air Toxics Priority Projects?

- Pursue voluntary initiatives to reduce point source air toxics
- Collaborate with each of Region 5 States
- Begin with a screening process to identify sources and risks
- Work jointly with industries to achieve emissions reductions

**Notes:**
Region V has initiated the RATPP to achieve voluntary reductions without expensive labor intensive risk assessments.
We are using screening tools to get at actual reductions more efficiently without long studies

## What Tools are Available?

- Risk Screening Software and Databases
- NATA - National Air Toxics Risk Assessment
- RSEI - Risk Screening Environmental Indicators
- Ambient Air Monitoring Data
- Emissions Inventory Databases
- TRI - Toxics Release Inventory
- NEI - National Emissions Inventory
- RAPIDS – Regional Air Pollutant Inventory Development System
- State and Local Inventories

**Notes:**
NATA Uses emissions inventories, and monitoring to model human exposure and estimate public health risks 
RSEI uses TRI data, population in proximity to emissions and toxicity values to estm public health risks
State operated monitoring network and submits data to the Nat’l Air Qual Syst database
At the end I will provide information on how to access these sources of information

## Description of Tools

- NATA and NEI
- Every 3 years, 1996,1999, 2002
- 2002 NATA coming soon
- Point, area and mobile sources
- RSEI and TRI
- Every year, RSEI through 2005, TRI through 2006
- Point sources only
- Industry self reporting

## Air Toxics Risk Screening Process

**Notes:**
This was developed by a member of our Section.  
It shows a flow chart of how we employ the various tools to screen air toxics
Monitoring compared to health stds

## Air Toxics Risk Screening Process (continued)

- Air Toxics Risk Screening Process (continued)

**Notes:**
After identifying sources and verifying the data
It is possible to select a specific facility source or sector to work with

## So What is Going on in Minneapolis/St. Paul?

**Notes:**
So we can apply these tools to a specific case study in Minneapolis/St. Paul

## Minneapolis/St. Paul Study Area

- Included 5 counties for analysis
- Hennepin, Ramsey, Washington, Dakota, Anoka
- Encompasses half the population of Minnesota
- In general, highest health risks are where the people are most concentrated

**Notes:**
Hennepin is Minneapolis and Ramsey is St. Paul and then the surrounding counties 
These are 5 of the most populous counties

## NATA Cancer Risks in Minnesota

**Notes:**
This is from the 1996 NATA which has a very nice mapping feature
The Twin Cities is located here in dark purple with the highest cancer risks state-wide
This shows risk from 54-190 in a million
> 100 in a million is of concern for lifetime of exposure
Which are levels of concern
White areas are near background cancer risks of 1 per million
Covers 33 HAPs of greatest concern in urban areas

## NATA Non-Cancer Hazard in Minnesota

**Notes:**
We consider cancer and non-cancer effects separately for risk and hazard estimates
These are non-cancer effects such as neurological or respiratory health hazards
The black area again is centered on the Twin Cities
Representing hazards of 5 to 27 times what is considered safe
This is for 33 of the pollutants of highest concern in urban areas

## RSEI Score of Pollutants (2000-2005, unitless relative score)

- C = metal compounds

**Notes:**
Now we are looking at RSEI data of relative risks
Remember, this is gathered annually from industry self reporting
This is 2000-2005 for the 6 pollutants of highest risk from point sources in M/StP
We see DI in blue for 2005 next green for Ni and Ni compounds
Yellow is manganese
The number by themselves mean nothing its relative to one another

## TRI Air Toxics Emissions (pounds, 2000-2005)

- C = metal compounds

**Notes:**
Let’s look at the 3 pollutants of highest risk DI Ni and Mn
Risks correspond to emissions in proximity to population and relative toxicity
These are absolute estm of pounds emitted in M/StP
DI risks are higher despite lower emissions due to the higher toxicity

## Diisocyanate Emissions by Source

**Notes:**
We used RSEI again to look at companies emitting Dis
As you can see Industry A, in blue, emitted most pounds per yr for 2003-2005
So we investigated further and here’s what we found

## Diisocyanates Follow-up

- US EPA met with the State
- State consulted Industry A
- Industry A realized it was incorrectly over-reporting DI emissions
- No significant risks from Diisocyanates
- Continued with our evaluation of nickel and manganese emissions

## Evaluating Risks and Emissions of Manganese (Mn) and Nickel (Ni)

- RSEI shows that manganese and nickel are the next highest sources of risk
- We can apportion risks by industry
- We can view air monitoring data for metals
- Risks are relative to population in proximity to source as well as overall emissions

**Notes:**
We can follow a similar process as we did for DIs
Plus we additionally have monitoring data

## Air Toxics Risk Screening Process

- <date/time>

- R. Trine, IATS, 2007

**Notes:**
Let’s look back our original flow chart
Our original three inputs are NATA RSEI and Monitoring
Let’s take a look at monitoring data in M/StP

## Monitoring Sites for Metals (TSP)

- TSP=total suspended particulates

**Notes:**
Here we have the location of total suspended particulates, monitoring sites in the Twin Cities
Anoka Cty has no monitors its to the north of Ramsey
The highest monitor annual mean for Ni is in Ramsey on the border with Hennepin Cty
The highest Manganese annual mean was in NW Hennepin Cty

## How do we Evaluate Health Risks from Monitoring Data?

- Compare ambient concentrations to health standards
- HQ < 1 considered “safe”
- RfC - Reference Concentration for non-cancer
- Conc/RfC = Hazard Quotient (HQ)

**Notes:**
So, when we look at monitoring data we can compare it to health stds
Ni and Mn have primarily non-cancer health effects
Ni compounds may be carcinogenic but we do not have data numbers on this
So let’s consider the noncancer effects
Mn- neurological
Ni - respiratory

## Air Monitoring Results for Twin Cities (2000-2007, ug/m3, TSP)

| Chemical | Mean Conc
Min - Max | RfC*
(ug/m3) | Hazard
Quotient |
| --- | --- | --- | --- |
| Mn & MnC | 0.022 – 0.049 | 0.050 | 0.44 – 0.98 |
| Ni & NiC | 0.0028 – 0.0039 | 0.090 | 0.31 – 0.43 |

- TSP = total suspended particulates
- C = metal compounds
- * IRIS and ATSDR

**Notes:**
Mean conc at the monitors
Here is the range from min to max
RfC are in the IRIS database or ATSDR database on-line
So we can calc HQ
We can see that only Mn is of possible concern

## So . . . What does all this mean?

- RSEI analysis shows that nickel (Ni) and manganese (Mn) are two pollutants which may be of concern in Minneapolis/St. Paul
- Monitoring data is available that shows that Mn levels may be elevated in the urban area
- Ni and Mn emissions may contribute to total health risks in the urban area

**Notes:**
In summary, we can say the following
Ask for questions at this point

## Where do we go from here?

- Verify data from manganese and nickel emissions sources
- Coordinate with the State to evaluate the significance of this data and determine a future course of action
- If necessary, work with the State and identified industries on possible voluntary nickel and manganese emission reductions

## Conclusions

- NATA and RSEI can be used to prioritize pollutants, industries and geographic areas of concern
- Monitoring data can be compared to health standards to show which pollutants are elevated
- Data must be evaluated critically with good science and sound judgment in light of the inherent uncertainties in screening tools
- These tools can guide us in making decisions on how to achieve public health risk reductions

**Notes:**
This is what I would like you to take away from this talk today

## On-line Resources                                                                                                                                                                                                                                                                                                                                                                                                           

- NATA – _[www.epa.gov/ttn/atw/NATA](http://www.epa.gov/ttn/atw/NATA)_
- RSEI – _[www.epa.gov/opptintr/rsei/](http://www.epa.gov/opptintr/rsei/)_
- Monitoring – _[www.epa.gov/air/data/reports.html](http://www.epa.gov/air/data/reports.html)_
- NEI – _[www.epa.gov/ttn/chief/net/index.html](http://www.epa.gov/ttn/chief/net/index.html)_
- TRI – _[www.epa.gov/](http://www.epa.gov/triexplorer)__[triexplorer](http://www.epa.gov/triexplorer)_
- RAPIDS – _[glc.org/air/rapids/](http://glc.org/air/rapids/)_

**Notes:**
I wanted to leave you with some information on how you can access 
these resources for yourself for studying other areas of the country