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Daily Maximum Eight-Hour Ozone Averages for April 2018

The table below lists the peak daily maximum eight-hour ozone concentrations measured in April 2018 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 2018POCMonitoring Site
Rural Retreat150454747495145483846NV56645046385561NA1Rural Retreat
AreaMonitoring SitePOCApril 2018POCMonitoring Site
Albemarle High School1484136484959485241505359685438385051NA1Albemarle High School
Frederick Co. Public School Maint. Dept.1384233444450444641504749625733323849NA1Frederick Co. Public School Maint. Dept.
Natural Bridge Station1473234474957415142505057675041385461NA1Natural Bridge Station
Harrisonburg VDOT1443834464753465139494654625241364648NA1Harrisonburg VDOT
AreaMonitoring SitePOCApril 2018POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School1473432474754425041474956665038385561NA1Herman L. Horn Elementary School
AreaMonitoring SitePOCApril 2018POCMonitoring Site
Charles City County1454039474759434948475053594640434547NA1Charles City County
Beach Road VDOT1473936474758444845455257605043424350NA1Beach Road VDOT
MSIC (MathScience Innovation Center)14641374747574549474851555849444544NVNA1MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCApril 2018POCMonitoring Site
NASA Langley Research Center1474543464855494750495452534537424447NA1NASA Langley Research Center
Tidewater Community College1464339484657484845464953554733394342NA1Tidewater Community College
VA Tech Agricultural Research Center1494339474958474847485455544735404450NA1VA Tech Agricultural Research Center
AreaMonitoring SitePOCApril 2018POCMonitoring Site
Aurora Hills Visitor Center137313743445643464148NV54655136353948NA1Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory1473739484959485145535356645142434148NA1Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County140323845NV56474845515355645138384050NA1Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area1414137464858475043535358625238334049NA1Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School1394135NV4756454840505058645235354149NA1Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows149434646485649514554485767554740NV55NA1Shenandoah National Park - Big Meadows
Long Park - Haymarket139403646NVNV465042525259655236354450NA1Long Park - Haymarket
Widewater Elem. School - Widewater1433737464855495147535255645139383950NA1Widewater 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.