Address: 1709 Lonedell Drive
Arnold West, MO 63010
County: Jefferson       
Pollutants Monitored: Ozone (O3),
fine particulate matter (PM2.5) and
particulate matter (PM10)
Site Coordinates
   * Latitude: 38.44862°
   * Longitude: -90.3958°
EPA Site ID: 29-099-0019

 

The federal season for ground-level ozone runs from March 1 through October 31. Ground-level ozone forms when pollutants emitted by cars, factories, power plants and other sources react chemically in the presence of heat and sunlight. Ozone at ground level is a harmful air pollutant as opposed to ozone in the upper atmosphere, which protects us from ultraviolet light. Exposure to ground-level ozone can contribute to health and environmental problems. Ground-level ozone is an irritant that damages lung tissue and aggravates respiratory disease.

As of 2015, the federal standard for ground-level ozone is 70 parts per billion (ppb), or 0.070 parts per million (ppm). 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.

Weekly summary of preliminary data from all ozone sites
• Eight-hour ozone design values
• Four highest eight-hour ozone values from beginning of ozone season
• Running list of sites with exceedances from beginning of season
• Monthly number of exceedances, 2016 and 2017
• Daily maximum average eight-hour concentration for each site from beginning of season

Preliminary one-hour averages from Arnold West in parts per million
• Ozone data in third and fourth columns on each day's first page
• "P" stands for primary monitor. "S" stands for secondary monitor.
• Data from 10 days ago through current date
• Central Standard Time

Preliminary eight-hour forward-rolling averages from all ozone sites
• Hourly data equals average of that hour and following seven hours.
• Data from 10 days ago through current date
• Central Standard Time
• Concentrations of ozone in parts per million (ppm)

Preliminary one-hour averages from all ozone sites in parts per million

• Data from 10 days ago through current date
• Central Standard Time

2016 exceedances for ozone

Graph of design values for ozone sites in St. Louis area, beginning in 2003

Department's webpage about ground-level ozone
• Description and health effects
• 2008 and 2015 standards and related documents

* Technical problems can affect ability to deliver quality data.
Access a table of symbols indicating specific problems.

EPA uses two ways to determine compliance with PM2.5 federal standards. One looks at data over a 24-hour period, and the other takes into account data for a whole year.

In December 2012, EPA set the annual PM2.5 standard at 12 micrograms per cubic meter, based on the three-year average of annual means. At that same time, EPA retained the 24-hour PM2.5 standard of 35 micrograms per cubic meter, based on the 98th percentile of 24-hour measurements, averaged over three years.

Weekly summary of preliminary data from all PM2.5 sites

Preliminary one-hour averages from Arnold West
• PM2.5 data in eighth column on each day's first page
• Data from 10 days ago through current date
• Central Standard Time

Preliminary one-hour averages from all PM2.5 sites
• Data from past three days through current date
• Central Standard Time

Graph of PM2.5 annual design values from St. Louis sites, beginning in 2003

Graph of PM2.5 24-hour design values from St. Louis sites, beginning in 2003

Department webpage about PM2.5
• Description and health effects
• 1997, 2006 and 2012 standards as well as related documents

* Technical problems can affect ability to deliver quality data.
Access a table of symbols indicating specific problems.

The EPA's standard for PM10 sits at 150 micrograms per cubic meter of ambient air,
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 standard is expressed as "expected number of days exceeding the standard."
The word expected indicates that air monitoring agencies typically do not measure PM10
every day.

Quarterly summary of preliminary PM10 data

Preliminary one-hour averages from Arnold West
• PM10 data in first column on each day's second page
• 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 values from all sites, beginning in 2003

Department webpage about PM10
• Description and health effects
• 2006 standard and related documents

* Technical problems can affect ability to deliver quality data.
Access a table of symbols indicating specific problems.