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Assessing Outdoor Air Near Schools

Life Skills of Trumbull County and Academy of Arts and Humanities - Warren, OH

EPA selected this school for monitoring because it is located near at least one large industry that is a source of air toxics emissions. The initial monitoring identified elevated concentrations of one key pollutant – manganese – that warranted additional monitoring at this school.  We are reporting concentrations of this key pollutant in the table below. Concentrations of other toxic air pollutants collected at the site are available as well (PDF) (3pp, 72k). (For example, manganese may be the key pollutant at a monitoring site but other metals, such as arsenic, measured in the sample also are available as indicated below in other pollutants monitored link.)

About the Data
The table below shows the level of the key pollutant in air samples collected at the monitoring site beginning in November 2010.   The table also includes individual “sample screening levels” for the key pollutant monitored at the school.  EPA developed these screening levels for this project to help the Agency and the community get an early sense of what the data were showing. The sample screening level is a level of pollution in the air that is below what we expect to cause health problems from short-term exposures – all day, every day over a period ranging up to at least a couple of weeks (longer, for some pollutants).  These screening levels are used only as guidelines for this project.

About The Table

Compare the sample results to the short-term screening level at the top of the table. Numbers at or below that level indicate the pollutant is not likely to pose immediate health concerns.

To use the screening level, compare it to each sample result:

  • a sample result at or below the sample screening level is not a concern for risk of health problems from short-term exposures.
  • a sample result above the screening level does not mean that there is a risk to children and adults at the school.  It is a signal for EPA to further evaluate those and subsequent results for that pollutant.  EPA is analyzing the potential for health concerns from long-term exposure now that the monitoring has been completed. Interim monitoring results are in the table below.
Additional Sample Results
Key Pollutants Arsenic
cubic meter)
cubic meter)
cubic meter)
Lead Non-FRM/FEM
cubic meter)
Sample Screening Level 150 30 6.4 150
11/10/2010 -- -- -- --
11/16/2010 1.73 -- 0.00042 10.3
11/22/2010 1.02 -- 0.00025 14.6
11/29/2010 3.26 1.02 0.00063 --
12/6/2010 0.11 0.745 0.0009 --
12/7/2010 -- -- -- 2.93
12/9/2010 0.93 1.57 0.00018 6.44
12/16/2010 1.2 1.39 0.0003 12.8
12/22/2010 0.62 -- 0.00021 5.67
12/28/2010 0.66 2.11 0.00032 5.85
1/3/2011 0.73 -- 0.00075 14.4
1/10/2011 0.74 -- 0.00061 12.7
1/12/2011 -- -- -- 2.82
1/20/2011 -- 1.05 -- --
1/24/2011 -- 1.73 -- --
1/27/2011 -- 0.985 -- --
1/31/2011 -- 1.1 -- --
2/8/2011 -- 0.758 -- --

–– = Sample not taken or invalid

Also monitored (PDF) (3pp, 72k)

To further evaluate sample results above a screening level, we considered:

  • information about the chemical and its health impacts,
  • information about collection of the sample (e.g., weather, activities around the monitor)
  • potential sources of the pollutant, and 
  • the pattern of levels across multiple samples within the monitoring period. 

If there had been a cause for concern before the sampling period was over, we would have informed the school and worked with the state or local air agency and with the school community to take appropriate action as quickly as possible.

About Some of the Pollutants Monitored
Some of the pollutants monitored (acrolein, acetaldehyde, benzene and 1,3-butadiene) may occur in the air at this school as a result of several different sources, including cars and trucks and the exhaust of other gasoline-powered engines. Because these types of sources are found almost everywhere where there are people, these pollutants are commonly elevated in urban areas across the country, and EPA has identified them as a national priority for reductions in the air in communities across the country.

The Monitoring is Complete
Once the full set of monitoring results for the key pollutants was collected,  EPA analyzed the results to estimate long-term average levels at the school.  We used that information to determine whether these levels are a health concern for school-age children, school staff, and the local community  exposed over many years.  In order to determine if a problem exists with air quality around the school, we evaluated:

  • measurements of pollutants in the air,
  • information particular to the school and nearby potential sources of these air toxics,
  • information on wind direction and rainfall which may influence concentrations of pollutants in the air,
  • information on typical national and regional levels of  the monitored pollutant, and
  • what is known about the relationship between exposure to these pollutants over several years and the risk of developing health problems.

If we had found a potential problem, we would evaluate if nearby sources of pollution are contributing to levels at the school and identify appropriate follow-up activities. 

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