Recent studies of over 400 women in New York City and Krakow have found that 5 year olds exposed in the womb to above-average levels of polycyclic aromatic hydrocarbons (PAHs), which are created from the burning of fossil fuels, score lower on IQ tests. A pregnant woman involved in the New York City study asserted, "It’s scary and alarming that we can live in a society where these things are happening and they go unnoticed."