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Daily Maximum Eight-Hour Ozone Averages for April 2017

The table below lists the peak daily maximum eight-hour ozone concentrations measured in April 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 SitePOCApril 2017POCMonitoring Site
Rural Retreat13440435050394452575960535863524839463246413735303447NA1Rural Retreat
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Albemarle High School13748365051383955576164555754545041533537453128323037NA1Albemarle High School
Frederick Co. Public School Maint. Dept.137474446494041515558645050565346415442NVNANANANANV36NA1Frederick Co. Public School Maint. Dept.
Natural Bridge Station13844355049394252555864525852524841493841442521282737NA1Natural Bridge Station
Harrisonburg VDOT13147404849373853565962525255524637524239442629322739NA1Harrisonburg VDOT
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School13743364938303644464851434843414031423234402624282939NA1Herman L. Horn Elementary School
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Charles City County1394743475040365153565452505248504042344042262231NV37NA1Charles City County
Beach Road VDOT14151444852403852566261605754515341473241442421282935NA1Beach Road VDOT
MSIC (MathScience Innovation Center)14050434555393552586261585754505140473544432224313340NA1MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCApril 2017POCMonitoring Site
NASA Langley Research Center13548464851423652595552584855475045444041473432394738NA1NASA Langley Research Center
Tidewater Community College1NANANV4652423852545753504249485447434041423432364633NA1Tidewater Community College
VA Tech Agricultural Research Center135444545504035495655525344534752434540394336273248NVNA1VA Tech Agricultural Research Center
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Aurora Hills Visitor Center13748454650373651606265NV4955525142503745352431322929NA1Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory13750454955433655606063555557535145483542392428313134NA1Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County13348454653NV3551595862535056535040503543382429313028NA1Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area132464343513832495356NV515153504636503638362225242434NA1Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School138484548NV37NV53586066545258555043554145452833302834NA1Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows1364747505242465460626557555858515154494648413648NVNVNA1Shenandoah National Park - Big Meadows
Long Park - Haymarket13949454755NV435358606556546455504355NV42443132323035NA1Long Park - Haymarket
Widewater Elem. School - Widewater13550454654423454585963535357535043503442362429313233NA1Widewater 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).
NA - Data not available.

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.