Air quality in Tehran, Iran : evaluating acute health effects and modeling the long-term spatial variability

The burden of disease due to air pollution can be very large because of its acute and chronic effects. This dissertation focused on these two key challenges in the megacity of Tehran, Iran. First, it assessed short-term exposure to ambient air pollutants and their association with daily mortality. Second, it assessed long-term exposures for different air pollutants, which is a prerequisite for the investigation of their chronic health effects. The first part found that the effect of air pollutants on mortality was immediate, and that it increased steadily over a period of weeks. The second part found that concentrations of various air pollutants were very high in Tehran, comparable with those reported for other megacities in Asia. Further, spatial land-use regression (LUR) models were developed for multiple pollutants, and showed that the city center was the most polluted area. Even so, more than 80% of Tehran had benzene concentrations above air quality standard of 5 µg/m3 set by European Union and Iranian Government. The thesis also included a systematic review of the global literature on LUR models for volatile organic compounds and found that the study in Tehran has been the largest to assess all BTEX (benzene, toluene, ethylbenzene, and xylenes) species in a megacity. The methods and models developed for this PhD dissertation opened up new avenues for the next generation of air pollution monitoring, modelling, and epidemiology in Iran.