EXCLUSIVE Children exposed to high levels of city air pollution while in the womb are nearly three times more likely to have mental deficiencies than other kids, an explosive Columbia University study has found. The analysis compared the learning ability of 183 3-year-olds from Harlem, Washington Heights and the South Bronx with the level of pollutants they were exposed to before birth. The moms wore air monitors while they were pregnant, and the kids are being studied over a number of years. The study found that 42 kids exposed to the highest readings of polycyclic aromatic hydrocarbons in utero -...