Air Quality is a companion article to Water Intake and Dehydration and Heat Safety
1. Current Air Quality
Fire & Smoke Map
Fire & Smoke Map
- Air Quality: Watch Duty App for Web Browser, Android & Apple iOS. (Select map layers you want)
- Air Quality: Seattle Air Now | South Park | WASmoke | WA Smoke Blog |
- Air Quality: PS CleanAir | PS Air Quality Sensor Map
- Air Quality: WA Dept of Ecology | Forecast Map
- Air Quality: AirNow.gov | Fire & Smoke Map |
- Air Quality: PurpleAir Monitors |
- Air Quality: IQair | Android App | Apple App | IQair Map
- Drought: Drought Forecast | NWS Climate Prediction Center |
- National Interagency Fire Center forecasts
- Pollen Count |
- National Weather Service Seattle Briefings & Information |
- Puget Sound Clean Air Agency Network Map | Sensor Map | Air Graphing Tool
- World's Air Pollution: Real-time Air Quality Index (waqi.info)
- Fire smoke is forecasted Here and Fire Smoke Outlook
- Fire smoke preparedness Here. (flyers for printouts)
- Wildfire Information DNR, InciWeb | Dashboard | NWCSS GIS MAP | NWCG.gov Map
- Fire and Smoke Map (airnow.gov)
- National Significant Wildland Fire Potential Outlook identifies areas by month for 4 months with above, below, and near normal significant fire potential.
- Lightning Map Here
2. Air Safety Levels

The Air Quality Index, or AQI, ranges from 0 to 500, based on the amount of pollution in the air at a given time. Ground-level ozone, particulate matter (both PM10 and PM2.5), carbon monoxide, sulfur dioxide and nitrogen dioxide are the primary parameters considered in the index.
Code Green (0-50) is Good
Code Yellow (51-100) is Moderate. Unusually sensitive individuals should consider limiting prolonged or heavy exertion.
Code Orange (101-150) is unhealthy for people within sensitive group: heart and lung disease, older adults, children and people with diabetes. People within Sensitive Groups should reduce prolonged or heavy exertion.
Code Red (151–200) is unhealthy for everyone. People within Sensitive Groups should avoid all physical outdoor activity.
Code Purple (201-300) is very unhealthy for everyone. Everyone should avoid all physical outdoor activity.
Code Burgundy (301-500) is hazardous for everyone. Everyone should avoid any outdoor activity.
Code Green (0-50) is Good
Code Yellow (51-100) is Moderate. Unusually sensitive individuals should consider limiting prolonged or heavy exertion.
Code Orange (101-150) is unhealthy for people within sensitive group: heart and lung disease, older adults, children and people with diabetes. People within Sensitive Groups should reduce prolonged or heavy exertion.
Code Red (151–200) is unhealthy for everyone. People within Sensitive Groups should avoid all physical outdoor activity.
Code Purple (201-300) is very unhealthy for everyone. Everyone should avoid all physical outdoor activity.
Code Burgundy (301-500) is hazardous for everyone. Everyone should avoid any outdoor activity.
3. Symptoms of Smoke Inhalation
4. Reduce Your Risk to Smokey Air
1) Stay indoors 2) Close windows 3) Filter/purify room air 4) Switch A/C to recirculate air
5) Use N95 masks 6) Seek air-conditioned spaces such as community rooms.
Compare Mask Ratings, Standards, and Filtration Effectiveness HERE
1) Stay indoors 2) Close windows 3) Filter/purify room air 4) Switch A/C to recirculate air
5) Use N95 masks 6) Seek air-conditioned spaces such as community rooms.
Compare Mask Ratings, Standards, and Filtration Effectiveness HERE
King County Gov: Wildfire smoke preparedness |
5. Choosing an Air Purifier
Considerations
- List of CARB-Certified Air Cleaning Devices (check to see if an air cleaner is CARB-Certified)
- HEPA Filter vs Other Technology
- CADR: Clean Air Delivery Rate, measured in Cubic Meters per Hour or Cubic Feet per Minute (CFM).
- Room Size in square feet or square meters (depends on CADR measurement)
- Air Changes per Hour: based on CADR and Room Size
- Purpose: Allergies & Asthma; Mold; Pets; Smoke & Odor; Virus & Bacteria
- Other Considerations: Purchase Cost; Cost of Filters; Noise Level (db(A)); Energy Consumption (W); Air Quality Sensor; WiFi Enabled; On/Off Timer; Dimensions; Weight.
- Note 1: Without CADR, efficiency rating like 99.8% efficiency doesn't tell you much.
- Note 2: BlueAir.com provides detailed comparisons between its models.
- Note 3: Consider purchasing an indoor Air Quality Meter (AQM) to let you know how your air purifier is performing. Here is an Example AQM on Amazon.
- Note 4: CO2 level meter in the above example will let you know if the air is getting too stale.
- normal outdoor level: 350 - 450 ppm
- acceptable levels: < 600 ppm
- complaints of stuffiness and odors: 600 - 1000 ppm
- general drowsiness: 1000 - 2500 ppm
- adverse health effects may be expected: 2500 - 5000 ppm
- In general - ventilation rates should keep carbon dioxide concentrations below 1000 ppm to create indoor air quality conditions acceptable to most individuals.
6. Choosing a Furnace Filter for your DIY Air Filter
Here are 2 charts comparing MERV ratings for particle sizes.
https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating
https://www.coolray.com/what-does-merv-rating-mean
3.0 - 10.0 Micron: MERV 5-8 Mold spores, hair spray, fabric protector, cement dust
1.0 - 3.0 Micron: MERV 9-12 Humidifier dust, lead dust, auto emissions, milled flour
0.3 - 1.0 Micron: MERV 13-16 Bacteria, most tobacco smoke, proplet Nuceli (sneeze)
FilterBuy.com Has a wide variety of air filters, helpful if you can't find what you need.
The thicker the furnace filter, the faster the air flows and the faster the room air is cleaned.
https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating
https://www.coolray.com/what-does-merv-rating-mean
3.0 - 10.0 Micron: MERV 5-8 Mold spores, hair spray, fabric protector, cement dust
1.0 - 3.0 Micron: MERV 9-12 Humidifier dust, lead dust, auto emissions, milled flour
0.3 - 1.0 Micron: MERV 13-16 Bacteria, most tobacco smoke, proplet Nuceli (sneeze)
FilterBuy.com Has a wide variety of air filters, helpful if you can't find what you need.
The thicker the furnace filter, the faster the air flows and the faster the room air is cleaned.
7. Construction of DIY Air Filters
Construction Notes:
1. The cardboard box that the fan or the furnace filters come in can be used for the base & shroud.
2. If you use 20x20x1 inch filters, the base should be a minimum of 21x21 inches.
3. If you use 20x20x2 inch filters, the base should be a minimum of 22x22 inches (You might have to flatten the sides of the fan or filter box to get 22x22 inches)
4. Any 2-inch-wide tape can be used to seal the filters, base, and fan together. If the tape is wider than 2 inches, it will cover parts of the filters. Duct tape is a good option.
5. Cut out the cardboard base & shroud ahead of time and keep them in storage with the furnace filters until you anticipate extreme air pollution -- then assemble the cube filter with fan. You can practice assembling the filters, base and fan to make sure they all fit as needed.
6. The shroud is not required. It might improve fan efficiency, based on an undocumented theory.
7. When making the cardboard shroud, draw 2 lines diagonally form the corners. Where the lines cross is the center of the circle you want to draw with a string and a pen.
8. If cutting out a circle is too challenging, cover the outside corners of the fan with triangular pieces of cardboard and tape them down.
9. Bottom line: Typical cost is $90 for filter cube with four 1-inch filters + box fan. If you have the money ($150-250) but not the dexterity for a DIY Air Filter Cube, consider a Hepa air purifier for home use.
10. If an air filter cube is not for you, consider a box fan with one furnace filter to clean your air. MERV 7 will get the dust and pollen out of the air. MERV 14 will remove smoke, bacteria and odors. MERV 14 20x20 furnace filters are easier to find online than in local stores.
11. Fan selection (refer to video below The Most for Your Money)
1. The cardboard box that the fan or the furnace filters come in can be used for the base & shroud.
2. If you use 20x20x1 inch filters, the base should be a minimum of 21x21 inches.
3. If you use 20x20x2 inch filters, the base should be a minimum of 22x22 inches (You might have to flatten the sides of the fan or filter box to get 22x22 inches)
4. Any 2-inch-wide tape can be used to seal the filters, base, and fan together. If the tape is wider than 2 inches, it will cover parts of the filters. Duct tape is a good option.
5. Cut out the cardboard base & shroud ahead of time and keep them in storage with the furnace filters until you anticipate extreme air pollution -- then assemble the cube filter with fan. You can practice assembling the filters, base and fan to make sure they all fit as needed.
6. The shroud is not required. It might improve fan efficiency, based on an undocumented theory.
7. When making the cardboard shroud, draw 2 lines diagonally form the corners. Where the lines cross is the center of the circle you want to draw with a string and a pen.
8. If cutting out a circle is too challenging, cover the outside corners of the fan with triangular pieces of cardboard and tape them down.
9. Bottom line: Typical cost is $90 for filter cube with four 1-inch filters + box fan. If you have the money ($150-250) but not the dexterity for a DIY Air Filter Cube, consider a Hepa air purifier for home use.
10. If an air filter cube is not for you, consider a box fan with one furnace filter to clean your air. MERV 7 will get the dust and pollen out of the air. MERV 14 will remove smoke, bacteria and odors. MERV 14 20x20 furnace filters are easier to find online than in local stores.
11. Fan selection (refer to video below The Most for Your Money)
- Lasko 20in Box Fan (best price and runs quiet)
- Lasko 20in Box Fan with MERV 10 furnace filter (can be replaced with MERV 14)
- Air King 20in Box Fan (best performance -- rated at 2400 CFM by manufacturer)
- Keep in mind, you will be running fans on low speed most of the time. Running on high speed for lengthy periods can cause the fan motor to heat up and present a safety problem.
- Make sure fan is UL or ETL listed for safety.
Terminology
Corsi-Rosenthal Cube/Box: 5 filters +Fan
Comparetto Cube: 4 filters + Cardboard base + Fan
Cardboard shroud reduces backflow caused by low pressure in box
CADR: Clean Air Deliver Rate
(CR Box is rated 600 to 800 cubic feet per minute for low to high speeds for particles >0.5 microns and MERV13)
MERV: Minimum Efficiency Reporting Value (MERV13 or higher removes smoke)
Sources:
Wikipedia
Aerosol Science & Technology
Corsi-Rosenthal Cube/Box: 5 filters +Fan
Comparetto Cube: 4 filters + Cardboard base + Fan
Cardboard shroud reduces backflow caused by low pressure in box
CADR: Clean Air Deliver Rate
(CR Box is rated 600 to 800 cubic feet per minute for low to high speeds for particles >0.5 microns and MERV13)
MERV: Minimum Efficiency Reporting Value (MERV13 or higher removes smoke)
Sources:
Wikipedia
Aerosol Science & Technology
DIY Sources:
- Corsi-Rosenthal Box - Wikipedia | Diagram
- Corsi-Rosenthal Cube - Encycla
- DIY box fan air filters – Corsi-Rosenthal box - Clean Air Crew
- DIY Air Purification Designs (edgecollective.io)
- THE Corsi/Rosenthal Box FAQ - Clean Air Crew
- A Variation on the "Box Fan with MERV 13 Filter" Air Cleaner
- How a MERV 13 Air Filter and a Box Fan Can Help Fight Covid-19
- Mass Production of Corsi-Rosenthal Box Fan-Filters / Twitter
- DIY Single Air Filter Instructions - Puget Sound Clean Air Agency
Five Demonstrations for Building a Corsi-Rosenthal (Covid Cube) Air Filter Box
The design was made for removing aerosols containing SARS-CoV-2 viruses.
It also works for smoke particulates, dust mites, and pollen, using MERV-13/14 furnace filters.
Notes:
1. Filters can be 20x20x1 or 20x20x2. Thicker filters offer less resistance to air flow.
2. Fan shrouds with circular 19" holes reduces air backflow.
3. Pleats in vertical alignment are less prone to sagging.
4. Observe the arrows on the filters to make sure air flows in the correct orientation.
The design was made for removing aerosols containing SARS-CoV-2 viruses.
It also works for smoke particulates, dust mites, and pollen, using MERV-13/14 furnace filters.
Notes:
1. Filters can be 20x20x1 or 20x20x2. Thicker filters offer less resistance to air flow.
2. Fan shrouds with circular 19" holes reduces air backflow.
3. Pleats in vertical alignment are less prone to sagging.
4. Observe the arrows on the filters to make sure air flows in the correct orientation.
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8. Air Quality Health Studies
Video: UW-led research links wildfire smoke exposure with increased dementia risk
November 25, 2024
Wildfire smoke may be worse for brain health than other air pollution
PBS 7-29-2024
The study found the odds of a new dementia diagnosis increased about 21% for every 1-microgram increase in the concentration of wildfire particles. That compared with a 3% increased risk for every 3-microgram jump in non-wildfire particles, concluded researchers from the universities of Washington and Pennsylvania.
PBS 7-29-2024
The study found the odds of a new dementia diagnosis increased about 21% for every 1-microgram increase in the concentration of wildfire particles. That compared with a 3% increased risk for every 3-microgram jump in non-wildfire particles, concluded researchers from the universities of Washington and Pennsylvania.
SciAm: June 29, 2023 / 6 min read
"Wildfires and Smoke Are Harming People’s Mental Health. Here’s How to Cope"
By Stephanie Pappas
"Wildfires and Smoke Are Harming People’s Mental Health. Here’s How to Cope"
By Stephanie Pappas
Breathing highway air increases blood pressure, UW research finds.
Even brief exposure to highway pollution could cause significant increases in blood pressure, a new study from the University of Washington has found, adding to a growing body of work correlating vehicle exhaust with negative health outcomes.
Even brief exposure to highway pollution could cause significant increases in blood pressure, a new study from the University of Washington has found, adding to a growing body of work correlating vehicle exhaust with negative health outcomes.
Long-term exposure to particulates from wildfire smoke linked to dementia risk, new study finds
Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the US
Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the US
Health Impacts of PM2.5
Fine-particle outdoor air pollution is the largest driver of air pollution's burden of disease worldwide.
Fine-particle outdoor air pollution is the largest driver of air pollution's burden of disease worldwide.
CA Groups Pressure Feds to Tighten Air-Quality Standards
The current EPA rules allow 12 micrograms of soot per cubic meter. The EPA proposes to take it down to 9 or 10, but clean-air groups want it lowered to 8.
Monica Embrey, California energy campaign director for the Sierra Club, said a standard of 8 micrograms would save 24,000 lives a year.
The current EPA rules allow 12 micrograms of soot per cubic meter. The EPA proposes to take it down to 9 or 10, but clean-air groups want it lowered to 8.
Monica Embrey, California energy campaign director for the Sierra Club, said a standard of 8 micrograms would save 24,000 lives a year.
Pollution mucks up the lungs’ immune defenses over time
Impaired lung immune function joins the list of pollution-related health problems.
Science News, by Aimee Cunningham, November 21, 2022
The new study indicates that older people have accumulated so much debris, “they may not be able to accumulate more,” impairing their ability to deal with inhaled material.
Impaired lung immune function joins the list of pollution-related health problems.
Science News, by Aimee Cunningham, November 21, 2022
The new study indicates that older people have accumulated so much debris, “they may not be able to accumulate more,” impairing their ability to deal with inhaled material.
Air pollution, depressive and anxiety disorders, and brain effects: A systematic review
Accumulating data suggest that air pollution increases the risk of internalizing psychopathology, including anxiety and depressive disorders. Moreover, the link between air pollution and poor mental health may relate to neurostructural and neurofunctional changes.
NeuroToxicology / Volume 93, December 2022, Pages 272-300
Accumulating data suggest that air pollution increases the risk of internalizing psychopathology, including anxiety and depressive disorders. Moreover, the link between air pollution and poor mental health may relate to neurostructural and neurofunctional changes.
NeuroToxicology / Volume 93, December 2022, Pages 272-300
Western wildfires’ health risks extend across the country
Those fires devastating communities in the West send bad air traveling, boosting emergency room visits in the East
By Megan Sever / June 17, 2022
ScienceNews.org
Those fires devastating communities in the West send bad air traveling, boosting emergency room visits in the East
By Megan Sever / June 17, 2022
ScienceNews.org
Estimated Mortality and Morbidity Attributable to Smoke Plumes in the United States:
Not Just a Western US Problem
Katelyn O’Dell, Kelsey Bilsback, Bonne Ford, Sheena E. Martenies,
Sheryl Magzamen, Emily V. Fischer, Jeffrey R. Pierce
First published: 21 August 2021
https://doi.org/10.1029/2021GH000457
Not Just a Western US Problem
Katelyn O’Dell, Kelsey Bilsback, Bonne Ford, Sheena E. Martenies,
Sheryl Magzamen, Emily V. Fischer, Jeffrey R. Pierce
First published: 21 August 2021
https://doi.org/10.1029/2021GH000457
Health Impact Assessment of the 2020 Washington State Wildfire Smoke Episode:
Excess Health Burden Attributable to Increased PM2.5 Exposures and Potential Exposure Reductions
Yisi Liu, Elena Austin, Jianbang Xiang, Tim Gould, Tim Larson, Edmund Seto
First published: 16 April 2021
https://doi.org/10.1029/2020GH000359
Excess Health Burden Attributable to Increased PM2.5 Exposures and Potential Exposure Reductions
Yisi Liu, Elena Austin, Jianbang Xiang, Tim Gould, Tim Larson, Edmund Seto
First published: 16 April 2021
https://doi.org/10.1029/2020GH000359
Time Magazine:
Why Extreme Heat Plus Pollution Is a Deadly Combination
By Emily Barone / July 28, 2022
https://time.com/6201615/heat-pollution-health-risk/
Why Extreme Heat Plus Pollution Is a Deadly Combination
By Emily Barone / July 28, 2022
https://time.com/6201615/heat-pollution-health-risk/
9. Volatile Organic Compounds
This web page focuses on particulate air pollution, but volatile organic compounds (VOC) are of concern also. Here are some resources:
- Volatile Organic Compounds' Impact on Indoor Air Quality | US EPA
- How to remove volatile organic compounds (VOCs) from your home?
- Amazon: Air Purifier for VOC Removal
- Amazon: An Air Quality Monitor for AQI and VOCs