What is asthma?

Asthma is a disease that affects the lungs and makes it hard to breathe. Symptoms include breathlessness, wheezing, coughing, and chest tightness. The causes of asthma are unknown but genetic and environmental factors can be involved. Five million Californians have been diagnosed with asthma at some point in their lives. Asthma is the most common long-term disease in children. African Americans and people with low incomes visit hospitals for asthma more often than other groups.


Why is this indicator included in CalEnviroScreen?

  • Outdoor air pollution can trigger asthma attacks or make asthma worse.
  • People with asthma can be especially susceptible to pneumonia, flu and other illnesses.


How is asthma measured in CalEnviroScreen 3.0?

  • There are different ways of measuring the rate of asthma in California. These include asthma prevalence (the number of people living with asthma), emergency department visits for asthma symptoms, and deaths from asthma.
  • The California Office of Statewide Health Planning and Development collects information on emergency department visits and hospitalizations from different causes in California.
  • Asthma emergency department data are currently the best available way of describing differences in asthma across the state at the census tract scale.
  • The indicator is the number of asthma emergency department visits per 10,000 people for the years 2011-2013.
  • A complete description of the Asthma indicator can be found in the CalEnviroScreen 3.0 report.


Where can I find more information about asthma and asthma emergency department visits?

CalEnviroScreen 3.0 Asthma Map

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