Address: 8227 S. Broadway
St. Louis, MO 63111
County: The city of St. Louis is not part of a county.
Pollutant monitored: Fine particulate matter (PM2.5) since 1999
Pollutants monitored in the past: Sulfur dioxide from 1969-2010; nitrogen dioxide from 1972-1981; carbon monoxide from 1972-1983; ozone from 1975-2003; and particulate matter (PM10) from 1988-2000. In addition, the department monitored for total suspended particles from 1965-1988; in the late 1980s, federal and, thus, state governments tweaked their monitoring efforts and transitioned from measuring concentrations of total suspended particles to monitoring PM10 and PM2.5.
Date established: Jan. 1, 1965
Site coordinates
* Latitude: 38.5425°
* Longitude: -90.263611°
EPA site: 29-510-0007

Photograph of the South Broadway Monitoring SiteEstablished in 1965, the South Broadway site is one of the oldest air quality stations in Missouri's network. It helps determine exposure of a segment of St. Louis' population to fine particulate matter (PM2.5). It is located in a residential neighborhood, and sources of air pollution most likely include traffic on nearby Interstate 55 and U.S. Route 267, known locally as Lemay Ferry Road.  

In the past, the station has monitored several other criteria pollutants besides fine particulate matter. The department's Air Pollution Control Program annually reviews its network of air quality monitors and recommends changes. Reasons for discontinuing monitoring have included budget crunches, shifts in population and low ambient air concentrations. For instance, in its 2011 Monitoring Network Plan, the program recommended deactivating several monitors, including the sulfur dioxide one at the South Broadway station. Why? The economic recession of the late 2010s.

Data on Fine Particulate Matter (PM2.5)*

PM2.5 describes particles smaller than 2.5 microns in size. Industrial and residential combustion as well as vehicle exhaust emit fine particles into the air. Fine particles also form in the atmosphere when chemical reactions transform gases, such as sulfur dioxide, nitrogen oxides and volatile organic compounds, into microscopic solid or liquid particles. Fine particles can affect the health of everyone, especially children, elderly and people who suffer from asthma and other pulmonary conditions.

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 from a whole year. In December 2012, EPA tightened the annual PM2.5 standard, setting it at 12 micrograms per cubic meter, based on the three-year average of annual means. 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
• Description of particulate matter and information on standard
• Annual and 24-hour PM2.5 design values
• Map of all PM2.5 monitoring sites in Missouri

One-hour preliminary averages from South Broadway
• Data from past 10 days through current date, Central Daily Time

Preliminary one-hour averages from all PM2.5 sites
• Data from past 10 days through current date, Central Daily 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's webpage about particulate matter
• Description of two groups of particulate matter: PM2.5 and PM10
• 1997, 2006 and 2012 standards for PM2.5 plus related documents
• 2006 PM10 standard and pertinent documents

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

Related Links

Missouri's mapped network of air monitoring sites

Department's webpage about air quality
• EPA's current and daily forecasts for St. Louis, Kansas City and Springfield
• Information about EPA's Air Quality Index
• Tips for improving air quality
• Suggestions for breathing better on action days — days forecasted orange (unhealthy for sensitive groups) to maroon (hazardous)

Real-time views from department's cameras in Kansas City and St. Louis

EPA's airnow.gov/ webpage
• Air quality forecasts for entire country
• EPA links to related information

EPA's Air Sensor Toolbox for Citizen Scientists