About 80 percent of ammonia released into the atmosphere comes from farming with ammonium-nitrate fertilizer, leading scientists to believe that SMOG IN CITIES is caused by that practice. Researchers led by civil and environmental engineering professor Mark Zondlo, however, have found a more likely cause: a city’s cars. Using tailpipe monitors, they determined that although cars release lower amounts of ammonia gas, they do so along with nitrogen oxides, which, when combined with ammonia, creates smog. They found that cars are particularly apt to emit ammonia during cold weather, when agriculture is dormant but smog levels peak. The study, published in Environmental Science and Technology in November, could bolster efforts to curb automobile emissions.
People’s faith in the “American Dream” depends upon their belief in SOCIAL MOBILITY, according to a study by psychology professor Susan Fiske and former Princeton postdoctoral research associate Martin Day, now a professor at Memorial University of Newfoundland. They studied the views of 500 people: Some read a passage about the United States as a country of high social mobility, while others read a description of low social mobility or no change at all. Those prepped with the first passage tended to be more supportive of the “system” and defended the status quo. Published in Social Psychological and Personality Science in November, the authors’ findings were consistent across the political spectrum from liberals to conservatives.
Police often show leniency with speeding drivers by writing down a lower speed (e.g., 9 mph over the limit instead of 10 mph) to let the driver avoid a steep jump in the fines. In a March working paper, economics Ph.D. candidates Felipe Goncalves and Steven Mello reported significant RACIAL BIAS in doling out that leniency. Analyzing tickets written by the Florida Highway Patrol between 2005 and 2015, they determined that about 20 percent of the officers were less likely to show leniency in ticketing to black and Hispanic drivers. In general, the researchers found that bias was lower among younger, female, and college-educated officers.