The maps were developed with the use of Google Street View cars that were equipped with a sensor system from enviromental sensor company Aclima (San Francisco, CA) designed to collect high-quality air pollution data on moving vehicles day after day. The data was collected over the course of a year in 78 square miles of Oakland, California, providing one of the largest data sets of air pollution ever measured of single city streets according to the researchers.
The new mobile technique is claimed to map urban air pollution at 100,000 times greater spatial resolution than is possible using traditional stationary government air quality monitors, of which there is typically only one for every 100 to 200 square miles. As a result, it enables users to see how dramatically air pollution can vary on even a block-by-block basis and could, say researchers, address major air quality monitoring gaps worldwide as well as shed light on the health effects on city dwellers.
"Air pollution varies very finely in space, and we can’t capture that variation with other existing measurement techniques," says Cockrell School of Engineering assistant professor Joshua Apte, who led the effort. "Using our approach and analysis techniques, we can now visualize air pollution with incredible detail. This kind of information could transform our understanding of the sources and impacts of air pollution."
The researchers' analysis also identified many recurring "hot spots" where pollution on a single block was consistently much higher than elsewhere in a neighborhood. These hot spots included the port, busy intersections, restaurants, warehouses, industrial plants, and vehicle dealerships.
"What surprised us is that there are consistently locations that can be as much as six times more polluted on one end of the block than on the other," says Kyle Messier, a UT Austin postdoctoral fellow and co-author of the study. "Among other things, this demonstrates that people are getting disproportionate exposures of unhealthy air at some locations."
The project is the latest phase of a partnership between the Environmental Defense Fund (New York, NY) and Google (Mountain View, CA), who have been working together since 2012 to map and measure health and environmental risks, and its approach was designed to be cost-effective and easily replicated. The Google cars drove more than 14,000 miles, and collected three million measurements of nitric oxide, nitrogen dioxide, and black carbon pollutants.
Apte hopes this mobile air quality monitoring approach expands to other major cities to help people make more informed decisions. "You could use this information when you're picking a school for your kids," he says. "Is there a school with a playground that might have better air quality because your kid has asthma? This hyper-local information about consistent air quality can be really useful for people, especially those who are vulnerable because of age or health condition."
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