Address: 20057 State Park Office Road
                Stoutsville, MO 65283
County: Monroe 
Pollutants monitored: Ozone (O3), sulfur dioxide (SO2), nitrogen dioxide (NO2)
and particulate matter (PM10)   
Pollutant monitored in the past: fine particulate matter (PM2.5)  
Site coordinates
   *Latitude: 39.4571°
   *Longitude: -91.78899°
EPA Site No.: 29-137-0001

The air monitoring station at Mark Twain State Park is not close to urban areas or large air pollution sources. Therefore, it provides important information on regional
background levels of air pollutant concentrations.

 

As of 2015, the federal standard for ozone is 75 parts per billion. An area is in compliance if the design value
is at or below this standard. A design value for ozone incorporates data from three years. The department and EPA
calculate the design value by 1) ranking the daily eight-hour ozone values for three consecutive years;
2) extracting the fourth-highest value for each year; and 3) averaging the three figures.

The state collects ozone data all year at Mark Twain State Park even though
the EPA has declared March 1 through October 31 ozone season.

Weekly summary of preliminary data from all ozone sites
   The summary only covers data collected during ozone season.

Preliminary up-to-date one-hour averages from Mark Twain State Park
   • Ozone data in fifth and six columns
      -- "P" stands for primary monitor. "S" stands for secondary monitor.
   • Data from previous 10 days through current date
   • Central Standard Time
   • Concentrations of ozone in parts per million (ppm)

Preliminary up-to-date eight-hour averages from all ozone sites
   • Eight-hour forward rolling one-hour averages
       -- Data listed for each hour equal the average of that hour plus the following seven hours
   • Data from 10 days ago through current date
   • Central Standard Time
   • Concentrations of ozone in parts per million (ppm)

Preliminary up-to-date one-hour averages from all ozone sites
   • Data from 10 days ago through current date
   • Central Standard Time
   • Concentrations of ozone in parts per million (ppm)

Graph of ozone design values for outstate sites, beginning in 2003
   
*Technical issues can affect ability to deliver quality data.
Click to access a table of symbols and explanations
of the problems indicated.

   In June 2010, EPA established a new one-hour SO2 standard of 75 parts per billion
and introduced a new form for determining the design value and, thus, compliance
with the standard. The new form requires three years of data — the average SO2 from each hour of the year.
The department and EPA calculate the design value, using the 99th percentile of daily maximum
one-hour concentrations, averaged over three years.

Weekly summary of preliminary data from all SO2 monitoring sites

Preliminary up-to-date one-hour averages from Mark Twain State Park
   • SO2 data in eighth column
   • Data from 10 days ago through current date
   • Central Standard Time

Preliminary up-to-date data from the state's SO2 sites
   • Data from 10 days ago through current date
   • Central Standard Time

Graph of design values for all SO2 monitoring sites, beginning in 2003

*Technical issues can affect ability to deliver quality data.
Click to access a table of symbols indicating particular problems.

  In February 2010, EPA established a new one-hour NO2 standard
of 100 parts per billion. An area is in compliance if the design value is
at or below the standard. The form to determine design value and, thus, compliance
requires three years of data — the average NO2 concentrations from each hour.
The department and EPA calculate the design value, using the 98th percentile
of one-hour daily maximum concentrations, averaged over three years.   

Weekly summary of all NO2 monitoring sites

Preliminary up-to-date one-hour averages from Mark Twain State Park
   • NO2 data in fourth column
   • Data from 10 days ago through current date
   • Central Standard Time

Preliminary data from all NO2 sites
   • Data from three days ago through current date
   • Central Standard Time

Graph of design values for all NO2 monitoring sites, beginning in 2003

*Technical issues can affect ability to deliver quality data.
Click to access a table of symbols indicating problems.

The EPA has set a standard for PM10 at 150 micrograms per cubic meter of ambient air (150 µg/m3 ),
averaged over a 24-hour day. A site does not meet this standard if it exceeds the level
more than once per year, averaged over a three-year period. The PM10 yardstick for compliance
is expressed as “expected number of days exceeding the standard." The word expected indicates that
PM10 is not always measured every day.

Summary of all PM10 sites

Preliminary up-to-date one-hour averages from Mark Twain State Park
   • PM10 data in last column
   • Data from 10 days ago through current date
   • Central Standard Time

Preliminary data from all PM10 sites
   • Data from past three days through current date
   • Central Standard Time

Graph of PM10 statistical information, beginning in 2003
  
*Technical issues can affect ability to deliver quality data.
Click to access a table of symbols indicating problems.