Monitoring Air Quality
What's In the Air We Breathe
The APCD has a network of 18 monitoring stations to find out what's in the
air we breathe. The data we collect is available on our
page and reported each year in our
Annual Air Quality Report. To view historical information on ozone and
particle pollution levels at Santa Barbara County monitoring stations, and
numbers of exceedances of standards by year, see
this page on the California Air Resources Board site.
air quality monitoring stations are small, portable structures containing
electronic instruments used to measure and record the concentration of various air
pollutants. Weather conditions such as temperature, wind speed, and
wind direction are also recorded. This helps the APCD track air quality trends and
evaluate the likely cause of high pollution levels.
Some pollutants are measured continuously 24
hours a day. Twelve stations continuously measure concentrations of ozone, and are shown in our
monitoring station network map.
Particulate matter less than 10 microns in diameter (PM10) and
particulate matter less than 2.5 microns in diameter (PM2.5) are measured
continuously at four stations: Santa Barbara, Goleta, Lompoc and Santa Maria. Data
are recorded in
real time by the APCD's Data Acquisition System and posted on the APCD's web
For more information on ozone, particulate matter, other pollutants,
and their health effects, see Air Pollutants and
The stations require regular visits by technicians to calibrate equipment, change
filters, and perform routine maintenance and repairs. Not every station measures every
pollutant. Some measure just one pollutant plus weather conditions. Some measure up to ten
pollutants plus weather conditions.
Each monitoring station is sited to meet one or more of the following objectives: (1)
to determine representative concentrations of air pollution in highly populated areas; (2)
to determine the impact of specific businesses or other sources of pollution; (3) to
determine general background pollution levels in areas not directly affected by cars,
businesses and other man-made pollution sources; and (4) to determine the highest
pollution levels in the county. The network of all stations combined must meet all four
Types of Stations
Stations fall into two primary categories: SLAMS and PSD stations.
Six SLAMS (State and Local Air Monitoring Stations) measure urban and regional air
quality. Two SLAMS stations are operated by the California Air Resources Board (Santa
Barbara and Santa Maria) and four by the APCD (Lompoc, Santa Ynez, El Capitan, and Goleta).
Five of these stations measure ambient concentrations of carbon monoxide,
ozone, nitrogen oxides, PM10, and sulfur dioxide.
Twelve PSD (Prevention of Significant Deterioration) stations are used to determine
baseline air quality and the impacts of specific operations, for example large oil and gas
facilities. These stations are generally located in the vicinity of the facility, and
measure specific pollutants emitted by the facility. Most PSD stations are
operated by the facility; four are operated by APCD. Some PSD stations have been located
in distant areas to measure background concentrations of pollutants, or to measure
regional pollutants, such as ozone, in areas downwind from the facility.
Data collected are summarized in regular required reports to the California Air
Resources Board and the U.S. Environmental Protection Agency, and in APCD's Annual Air
Quality Report. Data are also used for planning and permitting to help predict future
pollution concentrations using computer models. In an emergency, data on wind speed and
direction could help us predict the movement of a fire or toxic cloud, and determine
whether an evacuation is necessary.
We also use the data to watch air pollution levels on a daily basis. If any monitoring
station shows pollution levels above a certain threshold, the APCD is required to notify
public officials, schools, hospitals, convalescent homes, radio and TV stations, and to
advise people to curb their outdoor activities. Only rarely does the air in our county
reach a level that would require the APCD to make these public notifications.
Daily AQI |
Daily Ozone Summary |
Questions or comments?