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Peak Daily One-Hour Ozone Averages for May 2017

The table below lists the peak daily one-hour ozone concentrations measured in May 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 SitePOCMay 2017POCMonitoring Site
Rural Retreat1535252495142506247665730495861596146434533411Rural Retreat
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Albemarle High School1305348484639465059634238405852576355444233341Albemarle High School
Frederick Co. Public School Maint. Dept.1284844503936415057674333355647596856412546381Frederick Co. Public School Maint. Dept.
Natural Bridge Station1315054434841475352494537455759536350505030391Natural Bridge Station
Harrisonburg VDOT1285248464841445459633944415847586753404136431Harrisonburg VDOT
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Blue Ridge
Herman L. Horn Elementary School1465255435443485335455140476058626348534629401Herman L. Horn Elementary School
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Charles City County1285155494636414859724833315248616147454236301Charles City County
Beach Road VDOT1315153524237414857564735315548526350444437331Beach Road VDOT
MSIC (MathScience Innovation Center)1335054514436435061804836355449646552494343351MSIC (MathScience Innovation Center)
AreaMonitoring SitePOCMay 2017POCMonitoring Site
NASA Langley Research Center1345157485239435362716044395750666351464445351NASA Langley Research Center
Tidewater Community College1345060525140445360615644385653546252474142331Tidewater Community College
VA Tech Agricultural Research Center1335061504843435160565542365451606754504747291VA Tech Agricultural Research Center
AreaMonitoring SitePOCMay 2017POCMonitoring Site
Aurora Hills Visitor Center1345244464334425358715137346048648770534043331Aurora Hills Visitor Center
Fredericksburg Geomagnetic Observatory1335450474430415256735233335848556148434136271Fredericksburg Geomagnetic Observatory
Lee District Park - Fairfax County1325144454230425457755133346047597959474040331Lee District Park - Fairfax County
Sumerduck - C. Phelps Wildlife Mgmt Area1304944454036385154604926305444525750373834271Sumerduck - C. Phelps Wildlife Mgmt Area
Ashburn - Broad Run High School1335246494135435658694739386149607261483746381Ashburn - Broad Run High School
Shenandoah National Park - Big Meadows1355450474845435459615752465951596565514539431Shenandoah National Park - Big Meadows
Long Park - Haymarket1325246494235445559685134376250617060434045381Long Park - Haymarket
Widewater Elem. School - Widewater1325146474530435557664836335945557152434043351Widewater 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.