Figure 1
Exposure study sites. Maps of Grand Rapids (left) and southwest Detroit, MI (right) showing the locations of the study sites and major industrial sources for PM2.5 (USEPA-Air Data NET, 1999) (AI: auto industries, CE: cement industries, GY: gypsum industries, LI: lime industries, OR: oil refineries, PP: coal-fired power plants, ST: iron/steel industries, WI: waste incinerator, WW: waste water treatment and sludge incinerator).