SporeLag - Lagged and Moving-Average Exposure Features for Aeroallergen Epidemiology

Deterministic, group-safe utilities that transform daily environmental exposure series (pollen and spore counts, with support for other time-varying exposures such as ozone and particulate matter) into analysis-ready lagged and moving-average exposure features. Functions validate temporal regularity, assign ISO 8601 weeks and configurable seasons, impute missing daily values transparently, and construct lagged and windowed exposures suitable for environmental epidemiology and public health analyses.