Impact of Ambient Air Quality Standards revision on the exposure-response of air pollution in Tianjin, China.

To improve air quality, China issued a new version of Ambient Air Quality Standards in 2012, and Tianjin officially implemented these new standards in 2013. In order to observe whether the atmospheric quality and health had been improved after the release of the new standards, this study compared the exposure-response relationships between pollutant concentrations and daily deaths (and years of life lost, YLL) in the six central districts of Tianjin in 2007-2010 and 2014-2017, which were the two periods around the release of the new standards. The exposure-response coefficients were calculated by using the generalized additive model with the time series data. The results showed that the effects of PM and NO during 2014-2017 were lower than those during 2007-2010 (PM: 0.10<0.30, 2.07<4.52; NO2: 0.24<0.87, 6.39<11.98), while the results of SO were opposite (SO: 0.61>0.31, 10.31>1.64). And the excess deaths and YLL caused by the portion of the pollutants that exceeded the new standards also declined (PM: 156<206 persons, 3493<3913 person-years; NO: 64<136 persons, 1844<2895 person-years; SO did not exceed the new standards). The results proved that the new standards had a certain protective effect on the health of the population in the central districts of Tianjin. These findings may provide evidence for the formulation of public health policies and further improvement and development of the Ambient Air Quality Standards.