Air Quality Info


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air quality index

AQI Forecast

Nevada County

This forecast is for the pollutant: ozone (O3)

09 / 12 / 17 Tue 85 119
09 / 13 / 17 Wed 75 71
09 / 14 / 17 Thu 55 44
09 / 15 / 17 Fri 50 64
09 / 16 / 17 Sat 50 100
09 / 17 / 17 Sun 50 126
09 / 18 / 17 Mon 80
09 / 19 / 17 Tue 50
09 / 20 / 17 Wed 50
09 / 21 / 17 Thu 50
09 / 22 / 17 Fri 50

Despite having a relatively cool weekend in the foothills, we still ended up with high ozone levels. That was a surprise. However, temperatures are starting to cool down and I really, really, truly believe that the ozone levels are going to drop into the low end of Moderate and probably in the Good range the next few days. However, the ozone is far from over. I expect we will see some Unhealthy days before this ozone season ends sometime in October.

This forecast will be updated on Friday, September 22 or sooner if necessary.

In October of 2015 the EPA modified the National Ambient Air Quality Standard (NAAQS) for ozone. The old standard was 75 ppb (8 hour average). The new standard is now 70 ppb (8 hour average). Since the AQI values are based on the NAAQS, that means the AQI values are going to be a little higher this year even if the ozone values are identical to last year. Hence, we are going to have more days in the Moderate range in 2016, and even more days in the Unhealthy for Sensitive Groups range.

You may or may not have noticed, but one of the things that is unique and special about my ozone AQI forecast is that unlike almost everybody else, I let you see what the forecast was. That allows the user an opportunity to see how accurate my forecast is (or is not). That is a feature I wish the weather web sites and other AQI forecasters would add to their web pages.For Western Nevada County only, check out Ozone Maps at

To check out PM2.5 data for both Eastern and Western Nevada County, click here.  Be sure to set PM2.5 for the Parameter, and in Step 3 set the county to “Nevada”

Plumas County

To Check current PM 2.5 conditions click here. Be sure to set PM2.5 for the Parameter, and in Step 3 set the county to “Plumas”