Environmental Services Program

St. Charles Rock Road, St. Ann - Breckenridge Hills

Site Operator: St. Louis County Department of Health, Air Pollution Monitoring Program

Pollutants Monitored: Ozone (O3), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2), Carbon Monoxide (CO)


Ozone (O3)

Updated: Only historical data shown below. Instrument has been discontinued.

National Ambient Air Monitoring Standard:

Eight-hour Standard
The three-year average of the fourth highest daily maximum eight-hour average must not be greater than .08 ppm (parts per million). Data reported in three decimal places must be rounded to two decimal places.

One-hour Standard 1970 to 1997-no longer applies to any area in Missouri.
A one-hour average of 0.12 ppm (parts per million).

Exceedances allowed without a violation being recorded:
The term exceedance does not apply to the eight-hour standard. The three-year average is used to determine designation of attainment or non-attainment.

Disclaimer: Yearly and quarterly data shown below has been subject to data review and validation procedures by the reporting agency. Monthly data and data shown graphically is raw, unreviewed and unvalidated data.

Ozone (O3)

The units for all averages in this chart are parts per million.
Year Number of Days
Over Standard
Maximum
1-Hour Average
Maximum
8-Hour Average
Fourth Maximum
8-Hour Average
1993 0 .109 not available not available
1994 4 .149 not available not available
1995 1 .131 not available not available
1996 0 .109 not available not available
1997 0 .111 not available not available
1998 1 .146 not available not available
1999 1 .139 not available not available
2000 0 .122 not available not available
2001(Site moved to Breckenridge Hills)
2001 0 .090 not available not available
2002 11 .118 .103 .093
2003 5 .134 .106 .088
2004 0 .089 .072 .069
2005(Site Shut Down)


Nitrogen Dioxide (NO2)

Updated: Only historical data shown below. Instrument has been discontinued.

National Ambient Air Monitoring Standard: An annual average of 0.053 ppm (parts per million).

Exceedances allowed without a violation being recorded: None.

Disclaimer: Yearly and quarterly data shown below has been subject to data review and validation procedures by the reporting agency. Monthly data and data shown graphically is raw, unreviewed and unvalidated data.

Nitrogen Dioxide (NO2)

The units for all averages in this chart are parts per million.
Year Number of
Exceedances
Annual
Average
Maximum
1-Hour Average
1993 0 .018 .079
1994 0 .020 .085
1995 0 .022 .103
1996 0 .020 .077
1997 0 .020 .065
1998 0 .020 .080
1999 0 .021 .088
2000 0 .019 .085
2001 (Site moved to Breckenridge Hills)
2001 0 .017 .064
2002 0 .0164 .064
2003 0 .0158 .062
2004 0 .0123 .049
2005(Site Shut Down)


Sulfur Dioxide (SO2)

Updated: Only historical data shown below. Instrument has been discontinued.

National Ambient Air Monitoring Standard: A three-hour average of 0.50 ppm (parts per million) and/or a 24-hour average of 0.14 ppm (parts per million) and/or an annual average of 0.03 ppm (parts per million). Data reported in three decimal places must be rounded to two decimal places.

Exceedances allowed without a violation being recorded: One per year.

Disclaimer: Yearly and quarterly data shown below has been subject to data review and validation procedures by the reporting agency. Monthly data and data shown graphically is raw, unreviewed and unvalidated data.

Sulfur Dioxide (SO2)

The units for all averages in this chart are parts per million.
Year Number of
Exceedances
Annual
Average
Maximum
24-Hour Average
Maximum
3-Hour Average
Maximum
1-Hour Average
1993 0 .008 .033 .073 .123
1994 0 .008 .024 .089 .136
1995 0 .006 .024 .092 .147
1996 0 .006 .026 .071 .096
1997 0 .005 .030 .082 .109
1998 0 .005 .032 .094 .193
1999 0 .005 .030 .073 .087
2000 0 .005 .021 .042 .068
2001 (Site moved to Brekenridge Hills)
2001 0 .004 .014 .036 .057
2002 0 .0037 .023 .053 .091
2003 0 .0033 .015 .045 .090
2004 0 .0036 .011 .040 .066
2005(Site Shut Down)


Carbon Monoxide (CO)

Updated: Only historical data shown below. Instrument has been discontinued.

National Ambient Air Monitoring Standard: A one-hour average of 35 ppm (parts per million) and/or an eight-hour average of 9 ppm (parts per million).

Exceedances allowed without a violation being recorded: None.

Disclaimer: Yearly and quarterly data shown below has been subject to data review and validation procedures by the reporting agency. Monthly data and data shown graphically is raw, unreviewed and unvalidated data.

Carbon Monoxide (CO)

The units for all averages in this chart are parts per million.
Year Number of
Exceedances
Maximum
8-Hour Average
Maximum
1-Hour Average
1993 0 7.4 25.4
1994 1 10.0 19.5
1995 0 5.1 8.1
1996 0 4.3 9.3
1997 0 3.9 8.0
1998 0 4.0 10.9
1999 0 2.6 4.2
2000 0 3.5 4.3
2001 (Site moved to Brekenridge Hills)
2001 0 2.4 4.7
2002 0 3.2 6.8
2003 0 2.4 3.6
2004 0 1.9 2.6
2005(Site Shut Down)

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