California Asthma Emergency Department Visits

Asthma is one of the most common chronic diseases and recognized as a growing public health concern.

Emergency Department (ED) visit rates related to asthma are a leading indicator healthcare leaders use to track the effects of asthma, particularly on children 0-17 years old.

This project site provides an overview of key insights contained within asthma ED visit rate datasets on the CHHS Open Data Portal and other sources. It also provides an interactive map tool to help visualize how asthma ED visit rates vary across the state.

  • OverviewWhat is Asthma?

    Asthma is one of the most common chronic diseases and has been recognized as a growing public health concern. The effects of asthma include missed school and work days, disruption of sleep and daily activities, urgent medical visits for asthma exacerbations, and even death.

  • How is Asthma Measured?

    As with any disease, there are many ways to measure asthma severity in the population. Surveys reveal that about 5 million Californians have asthma.

    A subset of these sufferers will experience severe uncontrolled symptoms in a given year that cause them to visit a hospital emergency department (ED) for treatment.

    Measuring asthma-related ED visits can reveal the frequency of poorly controlled or severe cases of asthma in the population. Differences in the ED visit rate among different populations can suggest how to target additional investments in asthma care.

    Asthma indicator pyramid
    Asthma Surveillance Pyramid, developed by the Centers for Disease Control and Prevention, further described here.
  • How Common Are Asthma ED Visits?

    In 2012, there were about 186,000 ED visits for asthma in California, or 49.8 per 10,000 Californians of all ages. The rate for youth aged 0-17 was much higher, with 79.4 ED visits per 10,000 young Californians.

    The state’s Let’s Get Healthy California initiative has set a target of just 28 youth ED visits for asthma per 10,000 by 2022. Reaching this goal would represent an over 65% cut in the youth ED visit rate over the next seven years.

    • 185,831
      Total ED Visits
    • 79.4
      Average Rate Per 10,000,
      Age 0-17
    • 28
      2022 Target Rate Per 10,000,
      Ages 0-17
  • Geography: Adults

    Asthma is present throughout the state, though rates vary by location. Adult ED visit rates are somewhat higher in inland counties than in coastal counties.

  • Geography: Youth Ages 0-17

    Youth asthma ED visit rates, on the other hand, are much higher statewide and show much more variation among areas. Counties with the lowest rates tend to be northern and rural. Counties with the highest rates are concentrated in the San Joaquin and Imperial valleys.

  • Geography: Youth by Zip

    At the ZIP code level, distinctions among different areas become more pronounced. While youth asthma ED visit numbers are too small in certain areas to report reliable statistics (and thus not shown on the map), the remaining ZIP codes reveal strong geographic patterns.

  • Geography: Imperial Valley

    Youth asthma ED visits are particularly high in the Imperial Valley, south of the Salton Sea. This area is characterized by low incomes, low insurance coverage rates, and high outdoor air pollutant levels.

  • Geography: Los Angeles & Inland Empire

    Youth asthma ED visits in the Los Angeles and Inland Empire areas show the great variation in rates among populations within the same air basin. Among the many potential causes of this variation are differences in indoor air quality and lower levels of adequate preventative care among some populations.

  • Geography: San Joaquin Valley

    Some of the highest rates of youth asthma ED visits are in the central San Joaquin Valley from Merced down to Corcoran. Many of these ZIP codes rank among the most environmentally burdened in the state, characterized by high pollution and vulnerable populations.

  • Geography: San Francisco Bay

    The map of youth asthma ED visits in the San Francisco Bay Area reveals a pronounced difference among rates in different areas. Most of the areas with extremely high ED visit rates are in the East Bay, though there are some small pockets in San Francisco as well.

  • African Americans Have the Highest Asthma ED Visit Rates

    From 2005–2012, asthma ED visit rates among African Americans were 3–5 times higher than among Caucasians. Furthermore, African Americans are the only race/ethnicity group for which these rates have increased significantly over time.

    As the graph shows, this pattern holds for the youngest Californians, with African American youth ages 0-17 having much higher rates of asthma ED visits than youth of any other race or ethnicity.

    ED Visit Rates by Race/Ethnicity
  • Where To Go Next

    Scroll down to use the interactive map tool to learn how asthma ED visit rates vary across the state. You can view the data by county or zip, and by age range.

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Interactive Asthma Emergency Department Visit Rates by Geography

The map below shows 2012 emergency department visit rates for California counties and zip codes. Use the options on the side to toggle between age groups and map type. You can download the full data set, or select individual counties/zips to download.

2012 Emergency Department Visit Rates



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Resources Where Do I Go From Here?

Asthma Treatment

Did you know: Asthma patients who spend as little as 30 minutes with a health care professional to develop a personalized self-management plan have better disease control, but only about 40% of people experiencing asthma have ever received a written plan.

Experiencing asthma symptoms? Contact your health care provider.

Uninsured? Get signed up.

Want to learn more? Check out asthma info from the CDC, American Lung Association, and the American Academy of Allergy Asthma & Immunology

Plans and Solutions

Did you know: Asthma causes 11.8 million missed work days and 1.2 million missed school and daycare days in California annually, and direct and indirect asthma costs total $11.3 billion in California per year.

Want to know what California’s doing about it? Check out the state’s Strategic Plan for Asthma.

Want to talk to an expert? Contact the California Breathing team.

Data Sets

Did you know: The CHHS Open Data Portal contains much of the data used for this site, along with a host of other datasets covering medical facility performance, other public health indicators, and social services delivery.

Want to access the state’s data? Check it out.

Need other asthma data? Check out AskCHIS, BRFSS, the CDC, California Breathing, and the California Environmental Health Tracking Program.

Original Data Source: Emergency Department Database from the California Office of Statewide Health Planning and Development 2005-2012

Rates were obtained from the Environmental Health Investigations Branch of CDPH