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iSmog displays air quality and Spare the Air Day information for the San Francisco Bay Area and for specific cities including San Francisco, Oakland, San Jose, Walnut Creek, Pleasant Hill, San Ramon, Pittsburg, and Orinda. Users see a color-coded map indicating healthy, unhealthy, and dangerous levels of smog and other pollutants for the five air basins in the Bay Area, and can subscribe to tailored notifications for specific cities or areas.

Push notification alerts users with allergies or other environmental sensitivities when the air contains unhealthy levels of contaminants including ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and two sizes of particulate matter, all precursors of ozone. Notifications can be customized by level of sensitivity and by geographic area.

Additional notifications inform users about Bay Area Air Quality Management District (BAAQMD) Spare the Air days, when Bay Area residents are urged to take extra precautions like cutting back on driving and avoiding the use of oil based paints, gasoline-powered lawn mowers, or household aerosol products like hair sprays. In addition, the Bay Area Rapid Transit (BART) train network often runs free of charge on Spare the Air Days, and all Bay Area residents are
encouraged to take alternative modes of transportation, including San Francisco's MUNI train services, County Connection in Contra Costa County, or AC Transit in Alameda. Biking or walking to work is another great way to Spare the Air.

iSmog also provides an easy-to-access Twitter feed about Spare the Air Days, and contains useful information about how air quality scores are calculated, which can be used by local educators or nonprofits to discuss air pollution and issues unique to the Bay Area's air basins.

All Bay Area Counties (San Francisco, San Mateo, Santa Clara, Alameda, Contra Costa, Sonoma, Solano, Marin and Napa) are covered by the app, but 511 Contra Costa provides additional support to commuters in Contra Costa County through its website ( Air quality scores are made available publicly by the Bay Area Air Quality Management District (BAAQMD) at, and the app was designed by
Blinktag, Inc., a small Bay Area planning firm dedicated to uniting the fields of technology, mapping, transportation, and urban planning.

511 Contra Costa also makes tools available to environmental planners interested in other web or mobile-based applications at