Acute effects of ambient nitrogen oxides and interactions with temperature on cardiovascular mortality in Shenzhen, China.

Though inconsistent, acute effects of ambient nitrogen oxides on cardiovascular mortality have been reported. Whereas, interactive roles of temperature on their relationships and joint effects of different indicators of nitrogen oxides were less studied. This study aimed to extrapolate the independent roles of ambient nitrogen oxides and temperature interactions on cardiovascular mortality. Data on mortality, air pollutants, and meteorological factors in Shenzhen from 2013 to 2019 were collected. Three indicators including nitric oxide (NO), nitrogen dioxide (NO 2), and nitrogen oxides (NO X) were studied. Adjusted generalized additive models (GAMs) were applied to analyse their associations with cardiovascular mortality in different groups. The average daily concentrations of NO, NO 2 , and NO X were 11.7 μg/m3, 30.7 μg/m3, and 53.2 μg/m3, respectively. Significant associations were shown with each indicator. Cumulative effects of nitrogen oxides were more obvious than distributed lag effects. Males, population under 65 years old, and population with stroke-related condition were more susceptible to nitrogen oxides. Adverse effects of nitrogen oxides were more significant at low temperature. Impacts of NO 2 on cardiovascular mortality, and NO on stroke mortality were the most robust in the multi-pollutant models, whereas variations were shown in the other relationships. Low levels of nitrogen oxides showed acute and adverse impacts and the interactive roles of temperature on cardiovascular mortality. Cumulative effects were most significant and joint effects of nitrogen oxides required more attention. Population under 65 years old and population with stroke-related health condition were susceptible, especially days at lower temperature. [Display omitted] • Shenzhen was lightly polluted by nitrogen oxides from 2013 to 2019. • Low levels of nitrogen oxides affected adversely on cardiovascular mortality. • Cumulative effects of nitrogen oxides were most significant. • The adverse effects of nitrogen oxides were more obvious at lower temperature. • Joint effects were shown when different types of nitrogen oxides were combined. [ABSTRACT FROM AUTHOR]