This summer, wildfires in Eastern Washington, Canada, Oregon and California have been the source of the worst air pollution our jurisdiction has experienced in our memory.
With smoke in the air, it was easy to recognize and appreciate just how good our air quality usually is. We also saw that a lot more people were looking at the agency air quality gauges on our website.
Because of the recent focus on current air quality, I thought it would be a good time to explain where the agency monitors are located, what they measure and why. I hope you’ll keep checking the gauges often.
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Because building and maintaining a monitoring network is expensive and complex, it’s not possible to monitor air quality everywhere. So we are strategic about where we place monitors, locating them where we think they will provide the most valuable information.
Our ambient air quality monitors report air quality information you can see online. These monitors provide data about the quality of the air most of us are breathing in our communities. Our monitoring stations are in seven locations in our jurisdiction (Island, Skagit and Whatcom counties). These devices measure air quality continuously, and the online gauges are updated every hour.
Our ambient air quality monitors are located in downtown Anacortes, on March’s Point, on Yew Street in Bellingham, in Columbia Valley, on Loomis Trail Road near Lynden, at our agency office on South Second Street in Mount Vernon, and at Oak Harbor Middle School.
Most of our ambient air quality monitors are strategically placed to keep track of air pollution in populated areas. Others – like the monitor near Lynden – measure regional background air quality. The Columbia Valley monitor is helpful as we work with the community to improve an identified, localized air pollution problem caused largely by residential wood heating.
Most of our monitoring stations measure several air pollutants. It’s important to note that the ambient air quality monitors aren’t the only source of air monitoring data we have. We also require large emission sources in our jurisdiction to report air quality data from monitors located on their property. We audit their monitoring equipment and provide the data in monthly reports on our website.
The live color-coded gauges that you can look at on our website show information about ozone, fine particulate matter, or both. These gauges don’t indicate actual pollutant concentrations. Instead, the gauges translate pollutant concentrations into round numbers associated with general air quality categories (good, moderate, etc.).
Ozone: The U.S. Environmental Protection Agency has a saying about ozone: “Good up high, bad nearby.” Ground level, or bad ozone, is not emitted directly into the air. It’s created by chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight. Industrial facilities, electric utilities, motor vehicle exhaust, gasoline vapors and chemical solvents are some of the major sources of nitrogen oxides and volatile organic compounds. Breathing ozone can trigger a variety of health problems, particularly for children, the elderly and people of all ages who have lung diseases such as asthma. Ground level ozone can also have harmful effects on sensitive vegetation and ecosystems.
Ozone is measured in parts per billion. The current national health-based standard for ambient air is no more than 75 parts per billion for a maximum of eight hours. We expect EPA to revise this standard on or before Oct. 1, 2015.
We’re monitoring for ozone at Anacortes, Lynden and Mount Vernon.
Fine particles or PM 2.5: Fine particles, or particulate matter 2.5 (PM 2.5), refers to tiny particles or droplets in the air with a diameter of 2½ microns or less. There are about 25,000 microns in an inch. The larger particles in the PM 2.5 size range would be about thirty times smaller than the diameter of a human hair.
Particles in the PM 2.5 size range can be inhaled deeply into the lungs. Particle pollution is linked to a number of health problems, including coughing, wheezing, reduced lung function, asthma attacks, heart attacks and strokes. It also is linked to early death.
The national health-based standards are no more than an average of 35 micrograms of PM 2.5 per cubic meter of air in 24 hours and no more than an average of 12 micrograms of PM 2.5 per cubic meter of air in a year. That means that if the area is experiencing an hour of unhealthy air, the live gauge might be in the red for that hour. But if the air is good for the other 23 hours of the day, the air quality could still be better than EPA’s health-based standard.
We measure fine particle levels at all of our monitoring locations.
Our ambient air quality monitors measure other pollutants, too, but these pollutants aren’t displayed on gauges. Information about these pollutants is available in a table below the color-coded gauges you see online, and summarized with all of the air monitoring data we collect in a separate chart that we publish monthly online.
Here are the other pollutants we’re measuring with our ambient monitors:
Sulfur dioxide: Sulfur dioxide is one of a group of highly reactive gasses known as “oxides of sulfur.” In our region, the largest sources of sulfur dioxide within our regulatory authority are the four crude oil refineries. In our geographic area, Alcoa Intalco Works, the aluminum smelter near Ferndale, emits far more than the oil refineries. (By state law, air emissions from aluminum smelters are regulated by the state Department of Ecology.) Sulfur dioxide is linked with a number of adverse effects on the respiratory system.
The primary health-based EPA standard for sulfur dioxide is no more than 75 parts per billion in one hour.
We measure sulfur dioxide at Lynden, March’s Point and Anacortes, and we require and audit several industry monitors that measure sulfur dioxide.
Carbon monoxide: Carbon monoxide is a colorless, odorless gas emitted from combustion processes. Nationally and particularly in urban areas, the majority of carbon monoxide emissions to ambient air come from mobile sources such as cars and trucks. Carbon monoxide can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues. At extremely high levels, carbon monoxide can cause death.
The national health-based standard for carbon monoxide is no more than 9 parts per billion in 8 hours, and no more than 35 parts per million in 1 hour.
We measure carbon monoxide at our Lynden station only.
I hope you’ll keep using our website to check your current air quality. I also urge you to follow the state health guidance that applies when air quality is impaired. Our agency is working to make it easier for you to find our air quality information and to make the information we provide easier to understand when we launch our redesigned website at the end of the year.
▪ You can check current air quality online at http://www.nwcleanair.org/airQuality/current.asp.
ABOUT THE AUTHOR
Mark Asmundson is executive director of the Northwest Clean Air Agency, which works to preserve, protect and enhance air quality in Island, Skagit and Whatcom counties.