Air Quality

Why Is This Important?
Clean air is essential to human and environmental health.  Air pollution increases the risk of lung disease and contributes to a variety of health problems, including asthma, cardiovascular disease, and respiratory problems in children.  Air pollution can also damage local ecosystems.

What Is a Sustainable State?
A sustainable state is one where the air is clean and poses no threat to human health or environmental quality.

How Are We Doing?

Particulate matter
Suspended particulate matter (PM) is associated with asthma and other respiratory ailments, contributes to haze, and harms the environment.  The size of particles is directly linked to their potential for causing health problems, with the smaller particles most dangerous as they can lodge deep in the lungs.

The main source of PM is vehicles.  Other sources include power plants, industrial processes, and wood combustion (including wood-burning stoves).

  • In 2007, the state maximum 24-hour standard for PM of 10 microns or less (PM10) was exceeded on 1.6 percent of the days tested at the Redwood City air quality monitoring station.

Data source: Bay Area Air Quality Management District (2007 figures are

  • In 2006, federal standards for PM of 2.5 microns or less (PM2.5) were revised because of health risks associated with small particle pollution. 
  • In 2007, concentrations of PM2.5 were above the federal 24-hour standard on 1.1 percent of the days tested. 
  • The county received a “B” grade from the American Lung Association (ALA) for particulate pollution.  The ALA ranked the Bay Area among the top 25 metropolitan areas most polluted by short-term particle pollution in the country, however.

Ground-level ozone is the main component of smog.  It can be a trigger for asthma even at very low levels and can cause permanent lung damage after long-term exposure.  It can also damage plants and harm ecosystems.  Vehicles are the primary source of ground-level ozone.

  • In 2007, there were no days when ozone concentrations exceeded the state one-hour standard at the Redwood City station.
  • In the past decade, ozone concentrations have never exceeded the state one-hour standard more than once in a given year.
  • The county received an “A” grade from the ALA and with 12 California counties was ranked among the best in the country for ozone.

Other monitored pollutants include carbon monoxide and nitrogen dioxide.  In 2007, as in the past decade, there were no days when state or federal standards were exceeded for either of these pollutants.

Carbon dioxide, a major contributor to climate change, is discussed in the Carbon Dioxide Emissions indicator.


See appendix page 71, CLICK HERE. Researcher: Gladwyn d’Souza

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From the 2014 Indicators Report

1% of water in the county comes from recycled sources

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Quotable Quote

‟The first rule of sustainability is to align with natural forces, or at least not try to defy them.”—Paul Hawken