The table below lists the four highest daily maximum eight-hour ozone concentrations measured in 2017 in each community where the DAQ 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.) The fourth-highest average is in bold black (unless it is highlighted). All ozone measurements are in parts per billion. Times are shown in 24-hour format and correspond to the beginning of the eight hour average.
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|Area||Monitoring Site||POC||Highest||Second Highest||Third Highest||Fourth Highest|
|POC (Parameter Occurrence Code): a code used to correctly separate data from multiple instruments at one site.|
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
|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.