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How To Read AQI

How to read AQI

Green values, red values – how are you to make sense of the Santa Barbara County Air Pollution Control District‘s air quality index (AQI)? It looks overwhelmingly  Good , but there are  Unhealthy  values, too.

Everyone should know – it’s especially important at times like this when smoke from the Thomas fire has invaded Santa Barbara skies.

What's an AQI?

The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air. Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.E.P.A.

Colors signify risk

Source: the U.S. Environmental Protection Agency

PM2.5 dangers

Red is bad, here it stands for Unhealthy. Thursday Santa Barbara showed AQI readings of over 400 – in the Hazardous range.

But how do you make sense of the APCD’s chart that shows  Green ,  Yellow  and  Red  values?

Today’s Santa Barbara PM2.5 value of  Unhealthy (174)  is your critical indicator – in this case that means shelter in place, wear a N95 mask, and keep kids and seniors at home with all doors and windows closed. Pregnant women must take precautions to avoid exposure to woodsmoke.

No low threshold

PM2.5 is an abbreviation for particulate matter of 2.5 microns, substantially smaller than human hair, these particles can travel deep into your lungs and into your bloodstream. Read more at

Think a little exposure won’t hurt you? Fall and scrape your knee, or break a bone and you will heal, but exposure to PM2.5 has no similar remedy. Pregnant women must take precautions to avoid exposure to woodsmoke.

Remember, if you can smell it you’re being adversely affected by it. Avoid exposure to all woodsmoke.

The blue (Good) reading is only recording ozone. The red (Unhealthy) reading for Santa Barbara includes particulate matter, which is what makes woodsmoke so hazardous. Source: Air Bubbles, an iPhone app

Get an Air Purifier

Before I moved to Santa Barbara I lived in Portland, OR, where summer months are associated with forest fires. At times the prevailing winds would reverse and fill the city with smoke, so I studied and published a review of air purifiers. When I moved I brought them with me and I’ve been encouraging my neighbors to get them for their homes. You may need a couple, but you’ll be glad you have them. Read my air purifier review.

The N95 mask is good for short outings
The Honeywell HPA300, a top rated air purifier
Whirlpool Whispure – what would 2 of these do for your personal air quality?
The Santa Barbara Riviera – view from the Arlington Theatre – Friday December 8, 2017


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