5 County Map
Air quality forecast as of May 29, 2017
Mon
Tue
Wed
Thu
Fri
North Counties
41
40
G
G
M
Good
Good
Good
Good
Mod
Coast and Central Bay
41
40
G
G
G
Good
Good
Good
Good
Good
Eastern District
42
41
G
M
M
Good
Good
Good
Mod
Mod
South and Central Bay
38
37
G
G
G
Good
Good
Good
Good
Good
Santa Clara Valley
42
41
G
M
M
Good
Good
Good
Mod
Mod

Bay Area Air Quality Index

The Air Quality Index, or AQI, much like an air quality “thermometer,” translates daily air pollution concentrations into a number on a scale between 0 and 500. The numbers in this scale are divided into six color-coded ranges, with numbers from 0 to 300.

(0–50) Good

No health impacts are expected when air quality is in this range.

(51–100) Moderate

Unusually sensitive people should consider limiting prolonged outdoor exertion.

(101–150) Unhealthy for sensitive groups

Active children and adults, and people with respiratory disease, such as asthma, should limit outdoor exertion.

(151–200) Unhealthy

Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion. Everyone else, especially children, should limit prolonged outdoor exertion.

(201–300) Very unhealthy

Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion. Everyone else, especially children, should limit any outdoor exertion.

Stay informed!

Planning to bike to work or walk to school? Be sure to check the latest air quality alerts and forecasts before you head out! Bookmark this this page for forecasts, sign up for Spare the Air notifications via phone or email, or download our super useful iSmog App for your iPhone.

Spare the air and make a difference

The Bay Area Quality Management District set up the Spare the Air Program to spread awareness about the health effects of pollution and encourage people to learn more about pollution prevention. Get all the facts and sign up to receive either email or phone alerts about Spare the Air days and air quality alerts by visiting the Spare the Air website.

Subscribe via Email Get Voice Notifications

Free iSmog iPhone App

Our free iSmog app displays up-to-date air quality information for the entire San Francisco Bay Area on your iPhone, iPod Touch, or iPad. With just a tap, see an easy-to-understand map of environmental quality in the Bay Area’s five air basins. The app was built using data provided directly by the Bay Area Air Quality Management District (BAAQMD).

Use iSmog to monitor air quality conditions, be notified of when to expect poor air quality, and make more informed choices about environmentally friendly transportation options.

Read more about the iSmog App or download it for free from the App Store.
Download for free at the iTunes App Store