... Statistical Association, 92, 10 33 10 40.Environmental Protection Agency (19 70). The Clean Air Act (CAA); 42 U.S .C. s/s 74 01 et seq. (19 70) Clean Air Act and Amendments of 19 70 (PL 91- 604; 42 USC 18 57h-7 ... Single-index Models. ” Journal of the American Statistical Association, 92, 477–489.Chambers, J. M. and Hastie, T. (19 92). Statistical Models in S. Chapman and Hall, London.Clancy, L., Goodman, P., Sinclair, ... series studies of air pollution and mortality.• We calculate a closed form estimate of the asymptotically exact covariance matrix of the linear component of a GAM (the air pollution coefficients). Furthermore,...