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Peak Daily One-Hour Ozone Averages for April 2021

The table below lists the peak daily one-hour ozone concentrations measured in April 2021 in each community where the DAQ 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 2021POCMonitoring Site
12345678910111213141516171819202122
Clark County
Virgin Valley1555655565463565749545151626349484457595266541Virgin Valley
Paul Meyer1586262605157605458596057636250584858616460571Paul Meyer
Mountains Edge1556257575158585459595758626154584857576460431Mountains Edge
Walter Johnson1546263615356595557655956626351574858596463561Walter Johnson
Palo Verde1566165615255605560645858626050564757596461541Palo Verde
Joe Neal1556565655656615657655257615750554857586262541Joe Neal
Green Valley1556164614956565352595955636253564757586460611Green Valley
Jerome Mack1545863595158555454615952636350564858586259571Jerome Mack
Garrett Junior High1576263575159575751606052656457544860586762621Garrett Junior High
Jean1585559565054595257555258656452574957576559531Jean
Indian Springs1595962575349625455575051595549464754546059521Indian Springs

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 0.201 - 0.2011
401 - 500 0.505 - 0.604 Not Defined
500+ Not Defined Not Defined

PLEASE NOTE: This data has not been verified by the Clark County Department of Air Quality 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 Clark County Department of Air Quality 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.