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PM-2.5 (Local Conditions) Hourly Averages

Particle pollution (also called particulate matter or PM) is the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small, they can only be detected using an electron microscope. Particle pollution includes inhalable coarse particles, with diameters larger than 2.5 micrometers and smaller than 10 micrometers and fine particles, with diameters that are 2.5 micrometers and smaller. How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter -- making it 30 times larger than the largest fine particle. These particles come in many sizes and shapes and can be made up of hundreds of different chemicals. Some particles, known as primary particles, are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires. Others form in complicated reactions in the atmosphere of chemicals such as sulfur dioxides and nitrogen oxides that are emitted from power plants, industries and automobiles. These particles, known as secondary particles, make up most of the fine particle pollution in the country.

Fine particulates (PM-2.5) are generally emitted from activities such as industrial and residential combustion and from vehicle exhaust. Fine particles are also formed in the atmosphere when gases such as sulfur dioxide, nitrogen oxides, and volatile organic compounds, emitted by combustion activities, are transformed by chemical reactions in the air. Large-scale agricultural burning or sand storms can produce huge volumes of fine particulates. PM-2.5 data is the near real-time measurement of particulate matter 2.5 microns or less in size from the surrounding air. This measurement is made at local conditions, and is not corrected for temperature or pressure.

Use the controls below to select a different date or parameter and to control cell highlighting based on measured PM-2.5 (Local Conditions) levels. Click on the Generate Report button once you have made your selections.

Click on the Plot Data button once the tabular report has been generated to open a separate window containing data plots.
Select a date: Time Format: Select a Parameter:
PM-2.5 (Local Conditions) Highlights:  Moderate   Unhealthy for Sensitives   Unhealthy   Very Unhealthy   Hazardous  
Highlight validated data (Validated data has been manually reviewed by a data validator)
Select a Region:

PM-2.5 (Local Conditions) Hourly Averages for Friday, June 23, 2017.
measured in micrograms per cubic meter (local conditions)
Mid 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:0010:0011:00Noon 1:00 2:00
Clark County - all times are in PST
43  1 6.908.029.179.5811.4012.019.487.927.024.584.845.716.43 FEW NA 43  1 3 DAQ
298  1 7.1714.2610.3912.0616.3016.8610.991.76-3.43-6.01-6.20-1.85-5.94 FEW NA 298  1 3 DAQ
540  1 5.336.228.826.858.387.474.512.431.370.37-0.171.58 FEW NA NA 540  1 3 DAQ
561  1 8.389.7713.9210.2113.168.724.170.51- FEW NA 561  1 3 DAQ
1019  1 5.886.236.256.546.807.086.887.005.044.804.805.205.50 FEW NA 1019  1 3 DAQ
1501 9.0911.558.488.097.3310.077.525.686. FEW NA 1501 3 DAQ
2002  1 10.3711.458.498.658.187.185.364.954.956.254.454.695.39 FEW NA 2002  1 3 DAQ
8000  2 3.842.802.711.768.305.072.471. FEW NA 8000  2 4 Other
- These sites are maintained and operated by Clark County Department of Air Quality.
- These sites are maintained and operated by Paiute.

DAQ does not certify the validity or quality of data it hosts from other monitoring entities.
Maximum values for the day are bold within the table. Minimum values are bold italic.
† - This is an experimental measurement and readings may not be indicative of ambient conditions.

Key to PM-2.5 (Local Conditions) Highlight Colors:

The color-coding of the hourly PM-2.5 data is based on a 1-hour to 24-hour projection. This projection is based on statistics compiled over several years comparing the daily maximum 1-hour average to the midnight-to-midnight 24-hour average.
The table below shows the levels, color-coding, and suggested actions for both the 1-hour projection and the actual 24-hour standard.

Color Air Quality Rating 1-Hour
Actions to take
Moderate 13 - 35.9 12.5 - 35.4
  • No health impacts are expected when levels are within this range.
  • No health impacts are expected when levels are within this range.

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.