Avoid Breathing Wildfire Smoke Update

Avoid Breathing Wildfire Smoke – Stay Indoors When Air Quality is at Unhealthy Levels

November 16, 2018 

Aviso de Salud en Español  
Tránh Hít Khói Cháy Rừng – Tin Cập Nhật

SANTA CLARA COUNTY, CA – The County of Santa Clara Public Health Department is advising residents to take precautions due to unhealthy levels of smoke in the air. Wildfires in California are causing air pollution throughout the Bay Area. Elderly persons, children, and individuals with heart or lung disease are particularly susceptible to elevated air pollution levels and should take extra precautions to avoid exposure. The air quality index in our county has mostly been ranging from moderate (yellow) to unhealthy (red). In general, we advise everyone to use common sense and avoid prolonged exposure outdoors.

Smoke can irritate the eyes and airways, causing coughing, a dry scratchy throat, and irritated sinuses. Elevated particulate matter in the air can trigger wheezing in those who suffer from respiratory conditions, such as asthma or emphysema/COPD.

If you see or smell smoke, protect your health by avoiding exposure:

  • If possible, stay inside with windows and doors closed until smoke levels subside.
  • Reduce outside physical activity.
  • Set air conditioning units and car vent systems to re-circulate to prevent outside air from moving inside.
  • Make sure you don’t introduce other sources of indoor air pollution by avoiding smoking, frying food, burning candles, and running the vacuum.
  • Indoor air quality can be improved by using portable HEPA filters and frequently changing your home heating system’s integrated air filter with a properly rated particulate filter.

It is recommended that parents and school administrators check air quality readings before allowing children to practice outdoor sports while air quality is unhealthy.

What you should do depends on the air quality index. Due to the active wildfires and changing wind patterns, air quality can be variable and unpredictable. Air quality may improve at times or get worse, very quickly. Check the latest air quality data for your area by searching your location at airnow.gov. The air quality index in Santa Clara County during this wildfire event has ranged from moderate (yellow) to unhealthy (red):

Air Quality Index Levels of Health Concern




0 to 50

Air quality is considered satisfactory, and air pollution poses little or no risk.


51 to 100

Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.

Unhealthy for Sensitive Groups

101 to 150

Members of sensitive groups may experience health effects. The general public is not likely to be affected.


151 to 200

Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.

Very Unhealthy

201 to 300

Health alert: everyone may experience more serious health effects.


301 to 500

Health warnings of emergency conditions. The entire population is more likely to be affected.

Air Quality Guide for Particle Pollution chart above is also located
at https://airnow.gov/index.cfm?action=pubs.aqguidepart

The Bay Area Air Quality Management District has issued a Winter Spare the Air Alert asking residents to avoid adding additional air pollution activities such as lawn mowing, leaf blowing, driving, and barbecuing. Burning wood, firelogs, pellets, or any other solid fuels in your fireplace, woodstove, or other wood-burning device is illegal during a Winter Spare the Air Alert.

Regarding masks: the most important thing you can do is to stay indoors as much as possible when you smell or see smoke in the air. If you work outdoors, or prolonged outdoor activity is unavoidable, and there is heavy smoke, a properly fitted mask that filters out fine particles (such as an N95 or P100 respirator) can protect against harmful exposure. However, masks such as the N95 are not effective unless there is a good seal around nose and mouth. Additionally, it takes more effort to breathe through a well-fitted mask and can be more harmful than helpful for people with lung or heart conditions. Employees should work with their employers for direction on when/how to use N95 masks. Bandanas and typical surgical masks DO NOT protect against wildfire smoke particles.

For More Information: 

Masks and Wildfire Smoke FAQ 

Information on reducing particles using air cleaners and Indoor Air Tips 
Air Quality and Outdoor Activity Guidance for Schools  
Real time air quality from United States Environmental Protection Agency AirNow 
Wildfire Safety Tips are available from the Bay Area Air Quality Management District 
Air quality forecasts and health advisories from state Bay Area Air Quality Management District 

Santa Clara County  Clean Air Shelters List

Follow the Public Health Department on Facebook for updates


Media Advisory


©2024 County of Santa Clara. All rights reserved.