The study indicates that a global investment of $3.2 billion throughout 245 of the world's largest cities - that's about $4 per resident - could reduce pollution-related mortalities by anywhere from 2.7 to 8.7 percent, saving up to 36,000 lives every year. This level of investment could also reduce temperatures on the hottest days of the year for millions of people, save up to 48 billion kilowatt-hours of electricity annually and avoid up to 13 million tons of carbon dioxide emissions each year.