Assessing Outdoor Air Near Schools
Lamkin Elementary School - Cypress, TX
Results and Analysis of EPA’s monitoring
EPA selected this school for monitoring because it is located near a metal forging 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 hexavalent chromium 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||Levels of hexavalent chromium in the air at the school are below levels of concern for short-term and long-term exposure.|
|Key Pollutants Monitored||Hexavalent Chromium. Inhalation of hexavalent chromium at high levels can damage the respiratory system and cause cancer.|
|Next Steps||EPA will not extend air toxics monitoring at Lamkin Elementary School at this time because levels of hexavalent chromium in the air at the school are below levels of concern for long-term exposure to air toxics.
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 Texas Commission on Environmental Quality (TCEQ) will continue to oversee industrial facilities in the area through the facility’s Title V air permit and other programs.
Summary of Study Approach and Findings
- A monitor collected air samples from September 16, 2009 through December 8, 2009 at the Lamkin Elementary School in Cypress, TX. Hexavalent chromium was the key pollutant 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 hexavalent chromium emissions.
- Our analysis found that levels of hexavalent chromium in the air at the school are below levels of concern for long-term exposure.
- The analysis indicates that hexavalent chromium concentrations in the air near the school are influenced by a nearby metal forging facility.
- The concentrations of hexavalent chromium 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.
- The most recently available hexavalent chromium emissions estimates for the nearby facility from the 2008 TRI arelower than the estimates used to identify this school for monitoring.
- Because the analysis shows monitored concentrations of hexavalent chromium levels to be below levels of concern, EPA is not extending air toxics monitoring at Lamkin Elementary 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 hexavalent chromium concentrations and information on hexavalent chromium
- Measured wind direction and wind speed at the school
- Information about nearby sources of hexavalent chromium emissions
Analysis of Measured Hexavalent Chromium Concentrations:
1. Calculate the average: We calculated the average of the hexavalent chromium measurements (shown by the black diamond in the graph below). We compared this average to the long-term comparison levels (thick line on the graph below).
Result: The average hexavalent chromium level for the samples collected was below the long-term comparison levels. The health concern is low.
2. Calculate a range: To account for varying air concentrations of hexavalent chromium, we calculated a range around the average. We did this by estimating high and low values that the longer-term concentrations might reach using common statistical tools. We compared the highest point in the range (called the “upper bound”) to the long-term comparison levels.
Result: The high end of the range is lower than the comparison levels. The health concern is low.
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 hexavalent chromium.
|What we looked at||What we found|
|We looked at whether the wind data taken on the days we took measurements of hexavalent chromium 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 hexavalent chromium 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 patterns at that location. This suggests that, on a regional scale, the 3‑month sampling period may be representative of year-round wind patterns.|
Analysis of Information on Nearby Source of Hexavalent Chromium 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 approximately 80% of its normal capacity during the monitoring period, which is typical for this facility. Operations during 2009 were slightly higher (7%) than the previous year.|
|The concentrations of hexavalent chromium measured at the school are lower than those suggested by the information that helped identify this school for monitoring.|
|The nearby source of hexavalent chromium has a Title V operating permit issued by the State of Texas that includes operating requirements.|
Technical Report for School: Assessing Outdoor Air Near Schools: Lamkin Elementary School (Cypress, TX) (PDF) (20pp, 132k). The technical report is geared toward risk assessors, risk managers, and other regulatory agencies.