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Not just dust in the wind: Pima County issues air pollution advisory

Not just dust in the wind: Pima County issues air pollution advisory

  • EPA
  • Photo of Catalina Mountains from Downtown Tucson on Friday, Aug. 12.
    Pima CountyPhoto of Catalina Mountains from Downtown Tucson on Friday, Aug. 12.

The Pima County Department of Environmental Quality issued a "high pollution advisory" Monday because of the “unhealthy” levels of dust and other particles found in the air that morning due to dust blown into the Tucson region from Maricopa and Pinal counties Sunday night.

They’re advising older adults and anyone with heart or lung diseases to limit how active they are outside, at least for the morning. Elevated dust levels are expected to continue throughout the morning but will likely return to the healthy range by the afternoon.

The air quality monitor in Corona de Tucson was in the “unhealthy” range as of Monday morning, and several others were in the "moderate" range.

“Breathing small particles can irritate the respiratory system and worsen chronic heart and lung diseases," officials said.  The Environmental Protection Agency warns that some particles “can get deep into your lungs and some may even get into your bloodstream,” causing serious health problems.

The EPA also mentions “fine particles are also the main cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas.”

There are two types of particulate matter or pm. There is PM10, which are particles with diameters 10 micrometers and smaller, which can be inhaled. This might include dust, pollen and mold.

The more harmful types are PM2.5, fine inhalable particles with diameters that are generally 2.5 micrometers and smaller. This includes combustion particles, metals and organic compounds like methane, and can penetrate more deeply into the lungs because of their small size.

Some particles, such as dust, dirt, soot or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope, according to the EPA.

Because PM2.5 is finer, it poses a greater health risk as it’s more easily inhaled and travels more easily within the body. However, the EPA warned that some particles less than 10 micrometers in diameter can also cause serious health problems by getting deep into lungs and bloodstreams.

The average human hair is about 70 micrometers in diameter, making it 30 times larger than the largest fine particle, according to the EPA. Particles come in many sizes and shapes and can be made up of hundreds of different chemicals.

Some particulate matter is emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires, but most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles, according to the EPA.

PDEQ monitors air pollution in our region at 14 air quality monitoring sites, and they provide up-to-the-hour air pollution levels available online.

Bennito L. Kelty is’s IDEA reporter, focusing on Inclusion, Diversity, Equity and Access stories, and a Report for America corps member supported by readers like you.

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air pollution, pdeq, pima county, weather

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