Assessing Outdoor Air Near Schools
West Greene High School - Mosheim, TN
Results and Analysis of EPA’s monitoring
EPA selected this school for monitoring because it is located near a rubber and plastics manufacturing facility that is a source of air toxics emissions. Computer models were used to determine which air toxics may be present at elevated levels in the outdoor air near the school. These models showed that diisocyanates (hexamethylene-1,6-diisocyanate (1,6-HDI), methylene diphenyl diisocyanate (MDI), and 2,4-toluene diisocyanate (2,4-TDI)) could be present in the air around the school and prompted EPA to test to see if the levels present may be of concern.
|Primary Findings||Monitors located at the school did not detect any diisocyanates (1,6-HDI, MDI, 2,4-TDI) in any samples.|
|Diisocyanates (1,6-HDI, MDI, 2,4-TDI). Inhalation may affect the respiratory system if people are exposed to high levels.|
|Next Steps||EPA will not extend air toxics monitoring at West Greene High School at this time because diisocyanates (1,6-HDI, MDI, 2,4-TDI) were not detected in the air at the school.
EPA remains concerned about emissions from sources of air toxics and continues to work to reduce those emissions across the country, through national rules and by providing information and suggestions to assist with reductions in local areas.
The Tennessee Department of Environment and Conservation (TDEC)will continue to oversee the manufacturing facility through air permits and other programs.
Summary of Study Approach and Findings
- A monitor collected air samples from September 4, 2009 through November 9, 2009 at the West Greene High School in Mosheim, Tennessee. Diisocyanates (1,6-HDI, MDI, 2,4-TDI) were the key pollutants of interest.
- We posted individual air sample results on this website throughout the monitoring period to keep your community informed during the monitoring period.
- During the monitoring period, we evaluated the monitored concentrations to see if there was a concern from short-term exposures (e.g., several weeks).
- When the monitoring was complete, we analyzed the results to see if there was a concern from long-term exposures (over a lifetime).
- Also, when the monitoring was complete, we evaluated all the air samples from the on-site monitor. We also evaluated information on wind speed and wind direction from a weather monitor at the school, along with historical weather information and information about a nearby source of diisocyanate emissions.
- Our analysis found no detectable levels ofdiisocyanates (1,6-HDI, MDI, 2,4-TDI) in the air at the school.
- The analysis indicates that diisocyanates (1,6-HDI, MDI, 2,4-TDI) concentrations in the air near the school are not influenced by a nearby rubber and plastics manufacturer.
- The concentrations of diisocyanates (1,6-HDI, MDI, 2,4-TDI) measured at the school are lower than those suggested by the information that helped identify this school for monitoring.
- The process to identify schools for monitoring relied on emissions estimates and other information. Ambient air monitoring at the school allowed measurement of what was actually in the air.
- In 2007, the facility recognized that it had significantly over-reported its diisocyanate emissions and corrected its emissions report for the year 2005, the report year that was the basis for selecting the school for monitoring. Consequently, there are no reported NATA or TRI emissions estimates of diisocyanates for this source.
- Because the analysis shows the monitors did not detect any diisocyanates (1,6-HDI, MDI, 2,4-TDI), EPA will not extend air toxics monitoring at West Greene High School.
- Click here for additional information
How We Analyzed the Information We Collected at this School
The analysis considered whether the information collected at the school might raise concerns for the health of children or adults at the school. We looked at the following types of information:
- Measured diisocyanates (1,6-HDI, MDI, 2,4-TDI) concentrations and information on diisocyanates (1,6-HDI, MDI, 2,4-TDI)
- Measured wind direction and wind speed at the school
- Information about nearby sources of diisocyanates (1,6-HDI, MDI, 2,4-TDI) emissions
Analysis of Measured Diisocyanates (1,6-HDI, MDI, 2,4-TDI) Concentrations:
Result: Diisocyanates (1,6-HDI, MDI, 2,4-TDI) were not detected.
Analysis of Measured Wind Direction and Wind Speed at the School
We took measurements of wind direction and speed every day during the sample period. We took special note of the wind speed and direction on the days we took measurements of diisocyanates (1,6-HDI, MDI, 2,4-TDI).
|What we looked at||What we found|
|We looked at whether the wind data taken on the days we took measurements of diisocyanates (1,6-HDI, MDI, and 2,4-TDI) are similar or different from the wind patterns during the entire sampling period.||We found the wind patterns taken on the days we took measurements of diisocyanates (1,6-HDI, MDI, 2,4-TDI) to be generally similar to those observed during the entire sampling period.|
|We looked at whether the wind pattern during the sampling period is reflective of regional wind pattern over the long term.||Although we lack long-term wind data at the monitoring station, the wind patterns at the NWS station during the sampling period are generally similar to the historical long-term wind flow pattern at that location. This suggests that, on a regional scale, the 2‑month sampling period may be representative of year-round wind patterns.|
Analysis of Information on Nearby Source of Diisocyanates (1,6-HDI, MDI, 2,4-TDI) Emissions
|What we looked at||What we found|
|Whether we could determine if the source was operating as usual during the sampling period||This facility was operating at 50% of its normal capacity of near 100% during the sampling period. There was no detection of any diisocyanates (1,6-HDI, MDI, 2,4-TDI).|
|The nearby source of diisocyanates (1,6-HDI, MDI, 2,4-TDI) has operating permits issued by the State of Tennessee that includes operating requirements.|
|In 2007, the facility recognized that it had significantly over-reported its diisocyanate emissions and corrected its emissions report for the year 2005. This incorrect information was used in the modeling analysis for the schools selection.|
Technical Report for School: Assessing Outdoor Air Near Schools: West Greene High School (Mosheim. TN) (PDF) (16pp, 115k). The technical report is geared toward risk assessors, risk managers, and other regulatory agencies.