Relative risk of death from exposure to air pollutants: a short-term (2003-2007) study in Mexicali, Baja California, Mexico

Studies have shown associations between respiratory diseases and air pollutants in Mexicali, Mexico; however, none have addressed relative risk (RR) of death. By using Poisson regression models, we quantified the RR by exposure for: particulate matter (PM10, PM2.5), carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O-3), and sulfur dioxide (SO2) over a 5-year period and by climate (winter or summer). RRs were estimated utilizing each pollutant (single-pollutant model) on the same day as pollutant concentration were measured (lag 0) and up to 7 days later to the pollutant measurements (lag 7). Significant associations were found in RRs for one interquartile range increment of the corresponding pollutant, such as: PM2.5 lagged 5 days in winter and for the 5-year period (RR, 1.041 and 1.028, respectively); CO lagged 1 day in winter and for the 5-year period (RR, 1.044 and 1.032, respectively); NO2 on the current day (lag 0) in summer (RR = 1.037); and SO2 lagged one day for the 5-year period (RR = 1.023).