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Peak Daily One-Hour Ozone Averages for April 2017

The table below lists the peak daily one-hour ozone concentrations measured in April 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 SitePOCApril 2017POCMonitoring Site
Rural Retreat1384248535242455559626355626756514348395144393931361Rural Retreat
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Albemarle High School1405039535344415859636758595657524854454349383036321Albemarle High School
Frederick Co. Public School Maint. Dept.13749465052494253596267555361554947594546NANANANA251Frederick Co. Public School Maint. Dept.
Natural Bridge Station1414738535050445557606954605656504350434646282332301Natural Bridge Station
Harrisonburg VDOT1344942505343415558616456606156494355484448303137291Harrisonburg VDOT
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School1394640514534364647505446504445423544364045302830311Herman L. Horn Elementary School
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Charles City County1444949515545375455585858515552514344374546332631391Charles City County
Beach Road VDOT1465447505547395458727265625855544650394445342528331Beach Road VDOT
MSIC (MathScience Innovation Center)1445246476146375661737163615654534551414948282832351MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCApril 2017POCMonitoring Site
NASA Langley Research Center1385049525349375663585461505752534745464650403437551NASA Langley Research Center
Tidewater Community College1NANA46495751405760595654455551585145444648403435571Tidewater Community College
VA Tech Agricultural Research Center1404746485347375158585657485650554748444345412929521VA Tech Agricultural Research Center
AreaMonitoring SitePOCApril 2017POCMonitoring Site
Aurora Hills Visitor Center1365147515748395464657155526157534455395143273434331Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory1415247536050375762626858606257525249404946263232331Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County1335047505648375461616756526158524254374642273331331Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area1344846465745335256586253545752494153414140242926271Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School1365047515549415660627158566658524860434949333534341Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows1374951515550455561646959566060545357504852493355421Shenandoah National Park - Big Meadows
Long Park - Haymarket1375148525951425760636859587057524761474747393635321Long Park - Haymarket
Widewater Elem. School - Widewater1415347495749385759616955565957524752364544273230331Widewater Elem. School - Widewater
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.