Assessing Outdoor Air Near Schools
Colvin Elementary School - Wichita, KS
Results and Analysis of EPA’s monitoring
EPA selected this school for monitoring because it is located near three aerospace surface coating facilities that are sources of air toxics emissions. This school was selected in consultation with the Kansas Department of Health and Environment (KDHE) and the local air agency, the Wichita Air Quality Section of the Office of Environmental Health (Wichita AQS), and based on computer models which 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 and 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 Colvin 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 KDHE and Wichita AQS will continue to oversee the aerospace surface coating facilities through their air permits and other programs.
Summary of Study Approach and Findings
- A monitor collected air samples from August 23, 2009 through November 9, 2009 at the Colvin Elementary School in Wichita, KS. 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 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 the aerospace surface coating facilities.
- 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 chromium emissions data (2007 TRI) for one of the three sources is lower than those relied upon in previous modeling analysis (2005 TRI), while for the other two sources, the emissions are much higher (8,640 pounds in 2008 TRI vs. 120 pounds in 2005 TRI at one source; 780 pounds in 2008 TRI vs. 260 pounds in 2005 TRI at the other source).
- Because the analysis shows monitored concentrations of hexavalent chromium levels to be below levels of concern, EPA will not extend air toxics monitoring at Colvin 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 these three pollutants
- 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 is well 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 well below 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 are somewhat 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 site, the wind pattern at the NWS station during the sampling period is somewhat similar to the historical long-term wind flow pattern 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 Sources of Hexavalent Chromium Emissions
|What we looked at||What we found|
|Whether we could determine if the sources were operating as usual during the sampling period.||Information from the three nearby aerospace sources indicates that during the monitoring period, two of the three sources of interest were operating at 75% production level, while the third was operating at 50%.|
|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 sources of hexavalent chromium have operating permits issued by the KDHE and Wichita AQS that includes operating requirements.|
Technical Report for School: Assessing Outdoor Air Near Schools: Colvin Elementary School (Wichita, KS) (PDF) (27pp, 197k). The technical report is geared toward risk assessors, risk managers, and other regulatory agencies.