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Peak Daily One-Hour Ozone Averages for October 2017

The table below lists the peak daily one-hour ozone concentrations measured in October 2017 in each community where the Virginia DEQ measures ozone. Concentrations are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion, and are truncated to an integer number.

The values that go into this table are calculated at 3:30 am each morning. Therefore, the current day will almost always have very low hourly averages that are not truly representative of local conditions for the day. Because of this, the report does not display the current day's data.

Use the selection boxes below to customize this report. You may select a different month, a different year, a different report format, and whether or not to include time on the report. Click on the Generate Report button once you have made your selections.

Month:Year:Report Format: Include time:
Include time
Highlight using AQI colors
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
Rural Retreat139405246535532242935423825473838411Rural Retreat
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
Albemarle High School135445153586440232336322523373036351Albemarle High School
Frederick Co. Public School Maint. Dept.138435754516148232239162423323432381Frederick Co. Public School Maint. Dept.
Natural Bridge Station136434754525938182226343031353738381Natural Bridge Station
Harrisonburg VDOT136454754575942262140332427353533381Harrisonburg VDOT
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School139435151566038202729353124433737401Herman L. Horn Elementary School
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
Charles City County135414644424021171730262626213533381Charles City County
Beach Road VDOT138534948434126171827232626223529341Beach Road VDOT
MSIC (MathScience Innovation Center)139474659455129202138272926233633391MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
NASA Langley Research Center137424343474534232133293534293034371NASA Langley Research Center
Tidewater Community College137414240453929191924243231293035371Tidewater Community College
VA Tech Agricultural Research Center138454748443827192122283027253426391VA Tech Agricultural Research Center
AreaMonitoring SitePOCOctober 2017POCMonitoring Site
Aurora Hills Visitor Center145524953556839212348333127254035331Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory138414857525536192435283124273736341Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County147494852516138192146303026253735331Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area139425647475641192241283120363434391Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School142565653586742252340312922373436371Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows134464950545958242634353835444334381Shenandoah National Park - Big Meadows
Long Park - Haymarket144505752596642232245292722373335371Long Park - Haymarket
Widewater Elem. School - Widewater142494952566439162238323328283737361Widewater Elem. School - Widewater

Interpreting the AQI

Air Quality Index

Each NAAQS pollutant has a separate AQI scale, with an AQI rating of 100 corresponding to the concentration of the Federal Standard for that pollutant. Additional information about the AQI and how it can be used is available from the EPA's AirNow web site.

Place your mouse pointer over the scale displayed above to view information about the Air Quality Index, and each of the rating levels.

The actual index calculation is different for each parameter measured and is specified by the EPA. The following table shows the various breakpoints used in calculating the AQI.

AQI Breakpoint Definitions
AQI Range 1hr Ozone
in ppm
8hr Ozone
in ppm
0 - 50 Not Defined 0 - 0.054
51 - 100 Not Defined 0.055 - 0.070
101 - 150 0.125 - 0.164 0.071 - 0.085
151 - 200 0.165 - 0.204 0.086 - 0.105
201 - 300 0.205 - 0.404 0.106 - 0.200
301 - 400 0.405 - 0.504 Not Defined
401 - 500 0.505 - 0.604 Not Defined
500+ Not Defined Not Defined

PLEASE NOTE: This data has not been verified by the Virginia DEQ and may change. This is the most current data, but it is not official until it has been certified by our technical staff. Data is collected from Virginia DEQ ambient monitoring sites and may include data collected by other outside agencies. This data is updated hourly. All times shown are in local standard time unless otherwise indicated.