Study: Urban Air Pollution Varies from Block to Block

(June 5, 2017) An article published today in the journal Environmental Science and Technology demonstrates how a new approach to measuring air quality reveals pollution patterns at far greater detail than ever before. This scalable method could address major air quality monitoring gaps worldwide.

Researchers from Environmental Defense Fund and the Cockrell School of Engineering at The University of Texas at Austin joined forces with Google Earth Outreach and deployed Google Street View mapping cars equipped by Aclima to measure and chart air pollution in Oakland, CA, with unprecedented, highly localized precision, providing a detailed picture of where people are at greatest risk of breathing unhealthy air at 100-feet intervals.

The cars made three million unique measurements while driving more than 14,000 miles, creating one of the largest, most spatially precise datasets of mobile air pollution measurements ever assembled.

EDF and partners revealed the data in new, interactive maps that allow regulators and residents alike to see where elevated concentrations of dangerous air pollutants including black carbon, nitric oxide and nitrogen dioxide are located in certain sections of West and East Oakland. Studies have linked exposure to higher concentrations of these contaminants, typically a result of vehicle emissions, with heart disease, stroke and asthma.

“Air pollution is largely an invisible threat, one that poses especially disproportionate risks in lower-income areas like West Oakland. This new method allows us to visualize the data so communities and policymakers can identify the sources of harmful pollution and take action to improve safety and health,” Steven Hamburg, EDF Chief Scientist, said.

Conventional assessments of urban pollution rely on data from a relative handful of fixed air quality monitors, emission inventories and computer models to characterize air pollution in a city. In Oakland, an area of 78-square miles, three stationary, regulatory-grade air quality monitors measure urban background pollution levels. Data from these monitors combined with modeling help local and regional policy makers get a general sense of air quality and potential health risks. However, uncertainties remain about the variation in pollution levels in the areas between the monitors, making it difficult to know precisely where dirty air comes from or who is suffering the most.

“The new mobile technology allows us to measure air pollution levels where people actually breathe the air—at street level,” said Joshua Apte, assistant professor in the Department of Civil, Architectural & Environmental Engineering at UT Austin, and lead author of the study. “By allowing us to understand how air pollution varies between and even within city blocks, this technique will help policymakers and the public make smarter choices about how to reduce pollution and improve public health.”

This project is the latest phase of EDF’s partnership with Google, who have been working together since 2012 to map and measure a growing list of health and environmental risks, including hidden methane leaks from local natural gas systems.

“Google likes big challenges,” said Karin Tuxen-Bettman, Program Manager for Google Earth Outreach and lead for the air quality project at Google, “the mapping of air pollution, raising awareness of the problem, and enabling action to solve it — that’s a big challenge and we’re excited to play a part.”

For this study, EDF used two Google Street View mapping cars deployed by Aclima with a measurement system of fast-response air quality instrumentation. Engineers from UT Austin designed daily driving plans to ensure they captured data from each neighborhood at various times of the day, week and year. The cars drove about 435 miles of roadways an average of 30 times between May 2015 and May 2016.

In addition to technical partners, EDF collaborated with West Oakland Environmental Indicators Project (WOEIP), a community-based environmental justice organization in West Oakland, which served as a liaison and expert in the field of citizen science and applications of air quality data in Oakland.

“We know that it really matters where you live,” said Brian Beveridge, co-director of WOEIP. “This revolution in data gathering technology is proving what our neighbors have known for generations; it’s unhealthy to live near to freeways, truck routes, factories and ports.  The time is long overdue for policy makers to protect residents from industrial pollution.”

“Our findings validated community concerns about poor air quality near the port and major freeways,” Hamburg said. “But it’s also shocking to see how close homes and playgrounds have been built—and are continuing to be placed—near major pollution sources. This data can inform decisions about zoning and planning and result in concrete health benefits for communities.”

This work builds the foundational science that can be used in mapping cities around the world. 

EDF’s Air Quality Mapping project is a collaborative effort that includes: Environmental Defense Fund, whichplanned the project and convened the partners; Google Earth Outreach, whichprovided Street View vehicles and mapping technology; Aclima, which outfitted the cars with its platform to deliver dnvironmental intelligence through sensor networks; The University of Texas at Austin, which collaborated with EDF on the scientific elements of the study and developed the analytical approach to produce the map data; West Oakland Environmental Indicators Project (WOEIP) which provided the perspective of residents who live with diesel pollution; and Bay Area Air Quality Management District (BAAQMD), which provided data on regulatory-grade monitors, co-location services, and air quality expertise.