Frequently Asked Questions

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The Washington Air Quality Advisory (WAQA) is similar to EPA's national information tool, the Air Quality Index (AQI). Both use color-coded categories to show when air quality is good, moderate, or unhealthy. Both base those health assessments on the same hourly data collected at the Ecology and our partner monitoring stations. The difference is that WAQA shows health effect warnings at lower fine particle pollution (PM2.5) levels than the AQI does. In other words, Washington’s calculation is a more sensitive scale of caution as it triggers more severe health warnings sooner at lower pollution levels.

WAQA compared to AQI
Category Index Value WAQA Concentration (µg/m3) AQI Concentration (µg/m3)
Good 0-51 0-12.0 0-12.0
Moderate 51-100 12.1-20.4 12.1-35.4
Unhealthy for Sensitive Groups 101-150 20.5-35.4 35.5-55.4
Unhealthy 151-200 35.5-80.4 55.5-150.4
Very Unhealthy 201-300 85.5-150.4 150.5-250.4
Hazardous 301-400 >150.4 250.5-350.4
401-500 350.5-500

The PM 2.5 micrograms per meter-cubed readings in the right 2 columns show the breakpoints for air quality from Good to Hazardous for Ecology's WAQA and EPA's AQI.

Ecology developed the WAQA to provide accurate public information about the health risks of fine particle pollution (PM2.5). Scientific studies show that levels of PM2.5 in the air previously thought to be safe can cause illness and death. In fact, scientists have not been able to identify a safe level of PM2.5 pollution. The WAQA is more protective of human health than the AQI.

The Washington Air Quality Advisory (WAQA) is a unit-less index calculated from pollutant concentrations. The incremental color-coded categories serve to warn of the potential health risks of the current air quality. The health advisory numbers that you are seeing are based on scientifically derived mathematical calculations against the actual pollutant measured in the air. There are several measured pollutants affecting air quality: PM2.5, ozone, NOx, CO, and SO2. The most commonly measured and generally, the one of most concern in Washington State, especially during smoke events, is PM2.5. The scientific measurement of particulate pollution is micrograms per cubic meter (µg/m3). The is the weight of the pollutant particles in a known quantity of air.

Washington Air Quality Advisory for Smoke and Other Fine Particle Air Pollution
Air Pollution Category Meaning Precautions to Take
Good Air pollution is minimal and there is little health risk. None
Moderate People with asthma, respiratory infection, diabetes, lung or heart disease, or have had a stroke may begin to have breathing problems. People with asthma, respiratory infection, diabetes, lung or heart disease, or have had a stroke should limit outdoor activities or do activities that take less effort, such as walking instead of running.
Unhealthy for Sensitive Groups More people than average may have breathing problems or have worsened symptoms of existing asthma or lung disease. Sensitive groups include people with heart or lung disease, asthma, diabetes, infants, children, adults older than 65, pregnant women, or who have had a stroke. These people should limit time spent outdoors.
Unhealthy Many more people than average may have breathing problems or have worsened symptoms of existing lung or heart disease. Sensitive groups include people with heart or lung disease, asthma, diabetes, infants, children, adults older than 65, pregnant women, or who have had a stroke. These people should limit time spent outdoors.
Very Unhealthy Some healthy people can have breathing problems. People with asthma, lung and heart disease have an increased risk of symptoms or worsening of their disease. Studies show the number of people hospitalized for lung diseases can be 50 percent more than normal. Everyone should stay indoors, do only light activities, and keep windows closed if it is not too hot. Run air conditioners on re-circulate and close the outside air intake. Use indoor air cleaners with HEPA filters, if available. If you must be outdoors, wear an N-95 respirator mask. People with chronic diseases should check with their health care provider before wearing a mask. Check with your local health department for health information. People with asthma, lung and heart disease, or have had a stroke should check with their health care provider for advice about leaving the area. Anyone with shortness of breath, wheezing, chest pain, heart palpitations, extreme fatigue, or difficulty moving or speaking should call their health care provider or call 911.
Hazardous More healthy people are likely to have breathing problems. The people most susceptible are those with asthma or lung disease, diabetes, have had a stroke, infants, children, pregnant women, and adults older than 65. Studies suggest more people with asthma, lung or heart disease need medical attention. Everyone should stay indoors, do only light activities, and keep windows closed if it is not too hot. Run air conditioners on re-circulate and close the outside air intake. Use indoor air cleaners with HEPA filters, if available. If you must be outdoors, wear an N-95 respirator mask. People with chronic diseases should check with their health care provider before wearing a mask. Check with your local health department for health information. People with asthma, lung and heart disease, or have had a stroke should check with their health care provider for advice about leaving the area. Anyone with shortness of breath, wheezing, chest pain, heart palpitations, extreme fatigue, or difficulty moving or speaking should call their health care provider or call 911.

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There are several reasons the map displays a gray dot:

The website displays the most recent hour’s data even if it appears to be an hour or two behind. Here is why:
Ecology collects hourly data and labels it as top of the hour. This means that hourly data collected between 8:00 AM and 9:00 AM is labeled 8:00 AM The data from the most recently completed hour is collected from the monitor and displayed shortly after that hour is complete. Therefore, the website will display the 8:00 AM data shortly after 9:00 AM. Ecology collects all of its data in Pacific Standard Time year-round. This means that during Pacific Daylight Time (also called Daylight Savings Time) the data on the website will appear to be two hours behind the current time.

There are several ways to find meteorological data:

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The website includes reports that can be exported as a PDF or Excel.
Reports dropdown visual

  1. Click on Reports link on the main menu bar to display the list of reports.
  2. Select a report by clicking on it.
    • Some reports automatically generate data. Search boxes will filter the visible data to smaller datasets.
    • Others require data selections before running the report.
    • Click Display to launch the report.
    • The report will appear on the screen and displayed in table or graph format.
    • The icons in the top rightReport export buttons visual of the report header include options of viewing the report as a graph, table, and exporting. Most reports include Excel and some include pdf export options.

Data is also available from the Environmental Protection Agency (EPA) website at:
https://www.epa.gov/outdoor-air-quality-data

Near-Real Time (most recent) Information
The air quality map shows current air quality conditions. A dot represents a monitoring location and the color represents the current air quality at the location. In many cases, monitors closest to you will give you an indication of the air quality in your area. However, significant differences are also possible because of topographical and meteorological influences such as mountains and wind.

You can always click on a "dot" to get information that is more detailed on the pollutants measured, current concentrations, and monitor station information.

Data Reports
Reports are available in the "Reports" main menu bar. These reports present data in many different ways, and can be exported.

Ecology and its partners operate a large air-monitoring network with approximately 80 monitoring sites distributed throughout the state. Ecology continuously evaluates the effectiveness of its network to ensure that we are monitoring in the right locations. While we cannot monitor everywhere, we prioritize our monitoring efforts based upon the best available information and place monitors in communities and locations that are believed to be impacted by air pollution. In communities without a monitor, air quality scientists use the data collected from nearby sites and sophisticated air pollution models to estimate air pollution levels. Ecology also uses temporary mobile monitoring to characterize air pollution in areas where models suggest a potential air pollution problem.

There are several reasons data may be missing:

  1. Power outages at the site
  2. Site telecommunication problems
  3. The monitor wasn't operating properly

It depends. The most recently collected data have yet to be thoroughly reviewed for validity and should be considered preliminary. Ecology's quality assurance process involves a thorough review of the collected data to ensure that the data are of sufficient quality for intended uses. It typically takes about two months to complete the quality assurance process. This means that the data are accurate (valid) about 2 months after they have been collected. Summaries of such data will also be considered accurate.

The full web site is accessible, but not optimized, for small screens. A mobile app will soon be available for android or apple. Content will be limited on mobile devices.

Visit our report help page for guidance and a glossary of terms.