Air Pollution Measurements in Los Angeles and Orange County

Air pollution measurements in Los Angeles and Orange County

Last week, Orange County has daily, very visible smog. This has become quite common this last year. At one time last week, using the HazeToday app, I saw that our only online smog gauge in Anaheim, was registering the highest reading in the state at 110, colored Orange. It was hazy in all directions.  My eyes had been watering for days.

The worldwide air quality data center is run in China, at

Here is a photo of the color scale, attached to a combined reading of pollutants, called the Air Quality Index, or AQI.  The same colors are used with the same warnings but with different measures for individual pollutants.  The AQI is calculated from PM 2.5, PM 10, SO2, NO2, O3 ozone, and CO carbon monoxide.

0-50. Green is Good;

51-100. Yellow is Moderate;

101-150. Orange is Unhealthy for Sensitive Groups;

151-200. Red is Unhealthy, everyone may begin to experience health effects;

201-300. Blue is Very Unhealthy;

300+. Burgundy is Hazardous and a Health Alert.


Fortunately, the day in question, Anaheim was just into the Orange at 110.

Here is the history of Los Angeles – Long Beach – Anaheim number of days in the Orange and in the Red. It shows major progress to 2006, and then levels off at a lower rate.  The data is from

The average of the last five years is 22.4 days per year.  Still, PM 2.5 are particles smaller than 2.5 microns or micrometers, and are small enough to get into the alveoli of the lungs and stay there.  They can also go through the lungs into the bloodstream, and are not good to absorb at all, ever.  Being small, they can stay in the atmosphere longer.  “They can cause short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose and shortness of breath” according to the New York State Department of Health.

We show an overview of the pollution over Chinese cities filled with Red, Blue, and Burgundy, often in the 400s and 500s. We have great sympathy for the people living there. This shows that their motivation to get rid of coal is far greater than ours.





About Dennis SILVERMAN

I am a retired Professor of Physics and Astronomy at U C Irvine. For a decade I have been active in learning about energy and the environment, and in lecturing and attending classes at the Osher Lifelong Learning Institute (OLLI) at UC Irvine.
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