ParticulatesPortugal

An introduction to the traffic rules and road signs of Portugal. Learn about driving, road safety and much more in our illustrated book, with answers to frequently asked questions.

For informational purposes only. Always follow official regulations. Some content and images were created with AI assistance.


32. Particulates

Particulates, or particulate matter (PM), are tiny solid particles or liquid droplets suspended in the air. In road traffic, particulate emissions can come from vehicle exhaust, brake wear, tyre wear and road-surface wear, as well as dust that is disturbed by passing traffic.

Particulate matter is commonly classified by particle size. PM10 refers to particles with a diameter of up to approximately 10 micrometres, while PM2.5 refers to finer particles of up to approximately 2.5 micrometres. Vehicle emission standards, particulate filters and air-quality measures are used to reduce exposure to these pollutants.

Particulates
Smog over Connaught Place at sunset. (Delhi, India)
Wikimedia.org • wili hybrid • CC BY
What are particulates?

Particulates, or particulate matter, are very small solid particles or liquid droplets suspended in the air.

🔗 epa.gov • US EPA, Particulate Matter Basics

🔗 fhwa.dot.gov • US FHWA, particulate matter and road-transport sources

🔗 epa.gov • US EPA, AP-42 section 13.2.1.1, paved-road emissions and dust resuspension

What are PM10 and PM2.5?

PM10 refers to particles with a diameter of up to approximately 10 micrometres. PM2.5 refers to finer particles with a diameter of up to approximately 2.5 micrometres.

🔗 epa.gov • US EPA, Particulate Matter Basics

🔗 fhwa.dot.gov • US FHWA, particulate matter and road-transport sources

🔗 epa.gov • US EPA, AP-42 section 13.2.1.1, paved-road emissions and dust resuspension

Where do traffic particulates come from?

Road traffic can produce particles through engine exhaust, brake wear, tyre wear and road-surface wear. Passing traffic can also resuspend dust already present on the road.

🔗 epa.gov • US EPA, Particulate Matter Basics

🔗 fhwa.dot.gov • US FHWA, particulate matter and road-transport sources

🔗 epa.gov • US EPA, AP-42 section 13.2.1.1, paved-road emissions and dust resuspension

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