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Daily Maximum Eight-Hour Ozone Averages for May 2017

The table below lists the peak daily maximum eight-hour ozone concentrations measured in May 2017 in each community where the Virginia DEQ measures ozone. Concentrations that are rated Moderate or higher are color-highlighted based on the EPA-defined Air Quality Index colors. (See Interpreting the AQI.) All ozone measurements are in parts per billion.

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 with AQI colors
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Rural Retreat150515047454048604263522445545956544341382938231Rural Retreat
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Albemarle High School130514644433341495658403034574653604841372927271Albemarle High School
Frederick Co. Public School Maint. Dept.133473746363439485362403128534354614538274131331Frederick Co. Public School Maint. Dept.
Natural Bridge Station140485239453744514343363436555548574344432428221Natural Bridge Station
Harrisonburg VDOT132504544443941515559363932574555615038353338301Harrisonburg VDOT
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School147505440494045513140433542575553584348412435311Herman L. Horn Elementary School
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Charles City County126495146NV31NVNV5362453029494555574439373521251Charles City County
Beach Road VDOT130495048363339465252422729524448574540393421221Beach Road VDOT
MSIC (MathScience Innovation Center)131495147383140485669463031524556614844383825271MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCMay 2017POCMonitoring Site
NASA Langley Research Center132505348393241495965574132524758604942374232321NASA Langley Research Center
Tidewater Community College132485448393241495657534034514952604943353930291Tidewater Community College
VA Tech Agricultural Research Center131465448403441485655503633514955615045394226251VA Tech Agricultural Research Center
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Aurora Hills Visitor Center131494243382740505464383229574359726149374028241Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory131514745382540505364483130514550584640383522221Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County129494243362740505468443229564253665343373725251Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area126474243372436485158432527494148554433343123211Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School1315143463833425257654133315846576658443642NV231Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows140524945454042525858534447574962635245423443441Shenandoah National Park - Big Meadows
Long Park - Haymarket129504247382942515563453333574856665641374134341Long Park - Haymarket
Widewater Elem. School - Widewater129494445392440515459453231543750614937374023251Widewater Elem. School - Widewater
POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.
NV - There are not enough valid eight-hour averages for this day (there must be eighteen valid eight-hour averages).

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.