Methods: We used our institution’s Clinical Looking Glass software to compare daily AREDV and pollutant levels from 1999 and 2002, a year before and after the WTC attacks. We obtained daily nitrogen dioxide (NO2), sulfur dioxide (SO2), and ozone (O3) values from the National Climatic Data Center’s collection station in the Bronx. Using a Mann-Whitney test, we calculated median values for each variable and determined significant differences between the 1999 and 2002 values. We considered each season separately, such as Winter SO2 (1999) versus Winter SO2 (2002), due to seasonal variations of AREDV and pollutants.
Results: For median daily NO2, there were statistically significant increases from 1999 to 2002 in the spring (1999: 0.037 ppm; 2002: 0.046 ppm; p=0.039) and summer (1999: 0.033 ppm; 2002: 0.044 ppm; p=0.0002). Significant increases for median daily SO2 and O3 values between the years occurred in all four seasons (all p <0.0001). For median daily AREDV, significant increases occurred in the winter (1999: 11; 2002: 17; p<0.0001) and spring (1999: 9; 2002: 12; p<0.0001).
Conclusions: We observed an association between the WTC attacks and significant increases in O3 and SO2 for all seasons, and NO2 for the spring and summer; AREDV significantly increased in the winter and spring following the fall WTC attacks. Multivariate analyses are necessary to examine the relationships between AREDV and pollutants before and after the WTC attacks.