Address: 3247 Blair St.
                St. Louis, MO 63107
County: The city of St. Louis is not part of a county.
Pollutants Monitored: ozone (O3), sulfur dioxide (SO2),
nitrogen dioxide (NO2), fine particulate matter (PM2.5),
particulate matter (PM10), carbon monoxide (CO)
Pollutant monitored in the past: lead (Pb)
Date established: March 1, 1999
Site Coordinates
  
*Latitude: 38.656449°
   *Longitude: -90.198548°
EPA Site No.: 29-510-0085

The Blair Street air monitoring station provides data for assessing air quality in the north-central area of St. Louis.
The department established it in 1999, and since 2011, it has been part of the National Core (NCore) Network, which measures multiple air quality and meteorological parameters and provides data to determine compliance with federal
standards. The data from Blair Street play a key role in public information, evaluations of mathematical models of air quality, and scientific studies about health and environmental effects of ambient air pollutants. More information on the National Core Network.

The Blair Street station also is part of two other national networks. The Chemical Speciation Network (CSN) measures concentrations of organic and inorganic chemicals that contribute to airborne fine particulate matter (PM2.5). Click for more information on the Chemical Speciation Network. The National Air Toxics Trends Stations (NATTS) Network tracks long-term trends in levels of hazardous air pollutants and air toxics, and sites in the network to provide data for scientific
studies. More information on the National Air Toxics Trends Stations Network.

Ozone (O3) Data*

As of 2015, the federal standard for ground-level ozone is 70 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.

Although the ozone season runs from March 1 through October 31, the state monitors
ozone all year from Blair Street to meet the requirement for being an NCore site.

Weekly summary of preliminary data from all ozone sites

Preliminary up-to-date one-hour averages from Blair Street
  • Ozone data in fourth and fifth columns
      --"P" stands for primary monitor. "S" stands for secondary monitor.
  • Data from 10 days ago through current date
  • Central Standard Time
  • Concentrations of pollutant in parts per million (ppm)

Preliminary up-to-date eight-hour ozone averages from all sites
  • Eight-hour forward rolling averages
       Data listed for each hour are equal to 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 ozone averages from all sites

  • Data from 10 days ago through current date
  • Central Standard Time
  • Concentration of ozone in parts per million (ppm)

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

Additional information about ground-level ozone
   • Effects on health
   • Historical material

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

Sulfur Dioxide (SO2) Data*

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

Weekly summary of preliminary data from all SO2 monitoring sites

Preliminary up-to-date one-hour averages of SO2 from Blair Street
   • SO2 data in sixth column. Each day has three pages of data.
   • Data from past 10 days through current date
   • Central Standard Time

Preliminary up-to-date one-hour averages from all state SO2 monitors
   • Data from past 10 days through current date
   • Central Standard Time

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

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

Nitrogen Dioxide (NO2) Data*

In 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 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 preliminary data from all NO2 monitoring sites    

Preliminary up-to-date one-hour averages from Blair Street
  • Data in first column on second page. Each day has three pages of data.
  • Data from past 10 days through current date
  • Central Standard Time

Preliminary up-to-date data from all NO2 sites
  • Data from past three days through current date
  • Central Standard Time

Graph of NO2 Design Values, beginning in 2003

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

Fine Particulate Matter (PM2.5) Data*

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 made the annual PM2.5 standard more stringent, setting it 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 up-to-date one-hour averages from Blair Street
   • PM2.5 data in sixth column of second page. Each day has three pages of data.
   • Data from past 10 days through current date
   • Central Standard Time

Preliminary up-to-date 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

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

Particulate Matter (PM10) Data*

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 standard is expressed as “expected number
of days exceeding the standard.” The word expected is used
because PM10 is not always measured every day.

Quarterly summary of preliminary PM10 data

Preliminary up-to-date one-hour averages from Blair Street
   • PM10 data on second page, sixth column. Each day has three pages of data.
   • Data for past 10 days 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 design values for all sites, beginning in 2003

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

Carbon Monoxide (CO) Data*

Since 1971, EPA has maintained two standards for carbon monoxide. The eight-hour
standard stands at 9 parts per million, and the one-hour standard stands at 35 parts per million.
If design values are at or below the standard, then an area is in compliance. Design values
correspond to an annual average of eight-hour concentrations and one-hour concentrations.

Summary of preliminary data from CO sites

Preliminary up-to-date one-hour averages of CO from Blair Street
   • CO data in third column of first page. Each day has three pages of data.
   • Data from past 10 days through current date.
   • Central Standard Time

Preliminary up-to-date one-hour averages from all CO sites
   • Data from three days ago through current date
   • Central Standard Time

Graph of CO one-hour design values for all sites, beginning in 2003

Graph of CO eight-hour design values for all sites, beginning in 2003

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

Related Links

Missouri's network of air monitoring sites

National standard for pollutants

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

Daily Air Quality Forecast (AirNow) shows how current readings
at air monitoring sites rate on the EPA's Air Quality Index.
   Click on Missouri in the state box at the top of the home page
   to access information.

EPA's Air Sensor Toolbox for Citizen Scientists