405 4th St NW

PARTICLE FALLS is an animated light projection on the side of the Stevens Center building in Winston-Salem that reveals the invisible dangers in the air you are breathing. It is a dramatic public artwork that raises awareness of the presence and impact of particle pollution.

Viewing Opportunities




How does it work?

The PARTICLE FALLS animation is generated by translating real-time particulate matter data from the surrounding air on the corner of West 4th Street and Marshall Streets into imagery, using specialized computer software designed by the artist Andrea Polli. The particulate sensing is done using a nephelometer, a scientific instrument that takes in air samples and gathers data about the concentration of particle pollution. A computer program transforms the particulate data into visual bursts of bright color over a background of falling blue light. The more dots of color you see, the more particles there are in the air you’re breathing. The visualization updates with new air data in real time.

Notice what happens to PARTICLE FALLS when a diesel-powered or gasoline vehicle comes along. Compare that to a passing bicycle. How about an idling car? Or compare the number of particles on a clear day versus a hazy day. Wind patterns will also make unexpected real-time changes. This work emphasizes the fragility and unstable nature of our Earth’s atmosphere and the human role in increasing that instability. 

What is particulate matter?

 Fine particulate matter is a form of air pollution that occurs year-round and is a mixture of solid particles and liquid droplets, the smallest measuring 2.5 microns or less in diameter – just 1/30th the width of a human hair.  While larger particles known as soot affect your health, it is the tiny, fine particulate matter which is far more dangerous to your health because it can be inhaled deeply into the lungs, enter the bloodstream and cross the blood-brain barrier. Toxic gases also can “hitchhike” into your body on fine particles.  Sources of particle pollution in Winston-Salem include cars, trucks, diesel buses and construction equipment, landscaping tools, agriculture, industrial facilities, power plants, biomass, and residential wood burning.

Your Health and Particulate Matter

There is no safe level of particulate matter. Winston-Salem has been ranked as the 142 most polluted cities in 2016 and traditionally ranks above the national average of US cities for average annual particle pollution. We have improved in the past few years due to a strong regulatory environment. However, fine particle pollution – at any level – is linked to a long list of serious health problems including asthma, heart and lung disease, cancer, adverse birth outcomes and even premature death. Exposure here in Downtown Winston-Salem can be especially dangerous as the rows of tall buildings can create an urban canyon trapping air pollution right where you breathe.

Ranked for high ozone days out of 228 metropolitan areas


Viewing Opportunities

PARTICLE FALLS will be projected onto the western wall of the UNC School of the Arts Stevens Center and can be seen from many locations in downtown Winston-Salem. For best viewing, visit the corner of West 4th Street and Spruce Street every evening from February 22 to March 24. Free and open to the public.

February 22: Opening of PARTICLE FALLS

On-site demonstrations and explanations will be offered most nights at dusk by volunteers of Clean Air Carolina, our sponsors and other participating organizations concerned about air quality in the Triad region.

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