A team of Israeli researchers has developed a method to track pollution over the world’s mega-cities, a satellite-based process they say could help hold nations accountable for their pollution and promote cleaner
industrial practices. Using data collected by three NASA satellite systems, the researchers from Tel Aviv University (TAU) collected pollution trends for 189 cities with populations exceeding 2 million. According to Pinhas Alpert, head of TAU’s Porter School of Environmental Study, the research represents the first standardized global analysis of the smog levels in the atmosphere over the world’s largest cities. Based on the data, collected from 2002 to 2010, cities in Northeast China, India, the Middle East, and Central Africa saw the steepest rise in aerosol concentrations, with an average increase of 34 percent. The greatest improvements occurred in Houston, with a 31 percent decrease in aerosol concentrations; Curitiba, Brazil, a 26 percent decrease; and Stockholm, a 23 percent decrease.