One of the obvious lessons of the COVID-19 pandemic was the importance of air quality. As we know, the air-based transmission of a dangerous pathogen suddenly became a fundamental global concern. In addition, the measurable reduction in smog resulting from the first coronavirus lockdowns in polluted cities like Delhi, India brought a startling reminder of how dirty our skies had become.
In fact, the years immediately leading up to the pandemic exhibited decreasing air quality despite previous improvements. In the U.S., the 1963 Clean Air Act influenced reduced emissions of pollutants, including particulate matter 2.5, sulfur dioxide, nitrogen oxides, and VOCs—establishing a positive trend that lasted for several decades. However, air quality began declining again in 2017. By 2019, the World Health Organization reported that 43% of Americans resided in counties with unacceptable air.
Today, poor air quality is considered “the world’s largest environmental health threat,” according to the WHO, and results in approximately seven million deaths annually. What is worse, climate change only exacerbates the problem. According to the National Climate Assessment, global warming increases the likelihood of ground-level ozone and particle-based pollution. Thus, just as we must endeavor to reverse climate change, we must also redouble efforts to improve air quality.
A critical tool for this effort is monitoring. Advances in air quality sensing have resulted in more capable technologies, equipped with a greater number of sensors, that deliver a more accurate snapshot of atmospheric conditions. Highly sophisticated tools are also becoming more accessible. For example, Draper, Utah–based PurpleAir manufactures air quality sensors for community scientists, who can capture detailed data to share with the public. According to the EPA, the widespread distribution of such sensors—which are approaching the quality of scientific instruments—fills in local gaps to form a comprehensive air quality picture.
Meanwhile, scientists are also monitoring air quality from space. The Tropospheric Emissions: Monitoring of Pollution is a satellite-based tool that measures aerosol-based pollutants and generates more accurate air quality forecasts. The product of a collaboration between the EPA, NASA, NOAA, and the Smithsonian Astrophysical Observatory, TEMPO offers detailed monitoring of wildfire smoke, stratospheric ozone, nitrogen oxides, and other pollutants.
With more knowledge comes increased responsibility. In this spirit, pollution-reduction technologies are now proliferating, with novel strategies to integrate these tools into the built environment. The Smog Free Tower, a seven-meter-tall structure that cleans outdoor air, is a compelling example of how site-based mechanical infrastructure can have a palpable environmental impact. Developed by Studio Roosegaarde, which has offices in the Netherlands and the United Arab Emirates, the louver–clad tower actively removes pollutants from 30,000 m3 of air per hour via a positive ionization process.
The latest iteration of the firm’s Smog Free Project is a Smog Eating Billboard, a prototype developed in collaboration with UDEM University of Mexico. The so-called Pollu-mesh installation employs a photocatalytic coating application that reduces smog when activated by sunlight. The team claims that a single, treated billboard can purify the air for more than 100,000 people daily, providing the “clean air of 30 trees every six hours” for a period of five years, according to a project description from the firm.
Self-cleaning surfaces also contribute to minimizing the presence of particle-based pollutants. A team of researchers at UT Austin and North Carolina–based Smart Material Solutions has developed an anti-dust treatment that prevents particles from sticking to surfaces. The technology involves nanoscale manipulations of materials, transforming flat planes into microscopically scaled angular profiles that hinder the accumulation of dust. In tests, the team’s modified surface retained only 2% of particles, compared with 35% for a smooth sample. A target application for the team’s research is lunar spacecraft, which typically become coated with dust on the moon—but the strategy can also work to keep a wide variety of roof and façade surfaces clean here on Earth.
Left unchecked, air pollution will lead to a rising global death toll. By 2100, the proliferation of ground-level ozone and PM2.5 may result in estimated mortality rate increases of 14% and 16%, respectively. Like global warming, atmospheric air quality is another wicked problem that must be boldly addressed by the AEC industry. Distributed monitoring, remediating infrastructure, and superior material surfaces are a few of the efficacious tools to meet this challenge.
The views and conclusions from this author are not necessarily those of ARCHITECT magazine or of The American Institute of Architects.
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