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Substantial evidence has linked short-term exposure to ambient fine particulate matter (PM 2.5 ) with increased cardiovascular mortality, however, the specific chemical constituent and emission source responsible for this effect remained largely unclear. A time series Poisson model was employed to quantify the association of cardiovascular mortality with two sets of shipping pollution emission: nickel (Ni), vanadium (V) (the indices of shipping emission) and estimated shipping emission using a source apportionment approach in Guangzhou, China in 2014. We observed that Ni, V, and estimated shipping emission in PM 2.5 were associated with increased cardiovascular mortality, an inter-quartile range (IQR) increase in lag 2 Ni was associated with 4.60% (95% CI: 0.14%, 9.26%) increase in overall cardiovascular mortality, and 13.35% (95% CI: 5.54%, 21.75%) increase in cerebrovascular mortality; each IQR increase of lag 1 V was correlated with 6.01% (95% CI: 1.83%, 10.37%) increase in overall cardiovascular mortality, and 11.02% (95% CI: 3.15%, 19.49%) increase in cerebrovascular mortality; and each IQR increase in lag 1 shipping emission was associated with 5.55% (95% CI: 0.78%, 10.54%) increase in overall cardiovascular mortality, and 10.39% (95% CI: 1.43%, 20.14%) increase in cerebrovascular mortality. The results remained robust to adjustment for PM 2.5 mass and gaseous air pollutants. This study suggests that shipping emission is an important detrimental factor of cardiovascular mortality, and should be emphasized in air pollution control and management in order to protect the public health in Guangzhou, China. [ABSTRACT FROM AUTHOR]

While increasing evidence suggested that PM 2.5 is the most harmful fraction of the particle pollutants, the health effects of coarse particles (PM 10–2.5 ) have been inconclusive, especially on cerebrovascular diseases, we thus evaluated the effects of PM 10 , PM 2.5 , and PM 10–2.5 on stroke mortality in six Chinese subtropical cities using generalized additive models. We also conducted random-effects meta-analyses to estimate the overall effects across the six cities. We found that PM 10 , PM 2.5 , and PM 10-2.5 were significantly associated with stroke mortality. Each 10 μg/m 3 increase of PM 10 , PM 2.5 and PM 10-2.5 (lag03) was associated with an increase of 1.88% (95% CI: 1.37%, 2.39%), 3.07% (95% CI: 2.35%, 3.79%), and 5.72% (95% CI: 3.82%, 7.65%) in overall stroke mortality. Using the World Health Organization's guideline as reference concentration, we estimated that 3.21% (95% CI: 1.65%, 3.01%) of stroke mortality (corresponding to 1743 stroke mortalities, 95% CI: 896, 1633) were attributed to PM 10 , 5.57% (95% CI: 0.50%, 1.23%) stroke mortality (3019, 95% CI: 2286, 3777) were attributed to PM 2.5 , and 2.02% (95% CI: 1.85%, 3.08%) of stroke mortality (1097, 95% CI: 1005, 1673) could be attributed to PM 10-2.5 . Our analysis indicates that both PM 2.5 and PM 10-2.5 are important risk factors of stroke mortality and should be considered in the prevention and control of stroke in the study area. [ABSTRACT FROM AUTHOR]

Abstract The World Health Organization sets up the Ambient Air Quality Guidelines mainly based on short-term and long-term health effects of air pollution. Previous studies, however, have generally revealed a non-threshold concentration-response relationship between air pollution and health, making it difficult to determine a concentration, below which no obvious health effects can be observed. Here we proposed a novel approach based on the concept of "number needed to treat", specifically, we calculated the reduction in air pollution concentrations needed to avoid one death corresponding to different hypothetical concentration standards; the one with the smallest value would be the most practical concentration standard. As an example, we applied this approach to the daily standard of ambient PM 2.5 (particulate matter with aerodynamic diameter ≤2.5 μm) in four Chinese cities. The calculation was based on the association between daily mortality and ambient PM 2.5 , which was examined by a generalized additive model with adjustment of important covariates. Significant associations were observed between PM 2.5 and mortality. Our analyses suggested that it is appropriate to have 50 μg/m3 as the daily standard of ambient PM 2.5 for the study area, compared to the current standard of which were directly adopted from the national standard of 75 μg/m3. This novel approach should be considered when planning and/or revising the ambient air quality guidelines/standards. Highlights • There is limited method for air pollution standard formulation. • The "number needed to treat" was proposed as one potential method. • We examined the acute association between PM 2.5 and mortality in four Chinese cities. • We then calculated the reduction in air pollution concentrations needed to avoid one death. • Finally, we suggested that 50 μg/m3 should be considered as daily standard of ambient PM 2.5 in the study area. Capsule This study proposes a new "number needed to treat" approach to help establish or revise daily ambient air quality standards. [ABSTRACT FROM AUTHOR]

Previous research has reported the effects of long-term fine particulate matter (PM 2.5) pollution on years of life lost (YLL), but these effects may not represent the full impact. This study aims to estimate potential benefits in life time from adhering to daily ambient PM 2.5 concentration standards/guidelines. This study evaluated the relationship between daily ambient PM 2.5 level and YLL using a two-stage approach with generalized additive models and meta-analysis. Potential life expectancy gains were then estimated by presuming that daily PM 2.5 levels were in compliance with the Chinese and WHO standards. In addition, the attributable fraction of YLL due to excess PM 2.5 exposure was also calculated. During 2013–2016, 459,468 non-accidental deaths were recorded in the six cities of Pearl River Delta, China. Each 10 μg/m3 increment in four-day average (lag 03) level of PM 2.5 was related to an increment of 13.31 [95% confidence interval (CI): 5.74, 20.87] years of life lost. Implementation of the WHO guidelines might avoid 180,980.83 YLLs (95% CI: 78,116.07, 283,845.60), which corresponded to 0.39 (95% CI: 0.17, 0.62) years of increased life time per death. Additionally, an estimated 0.15% (95% CI: 0.06%, 0.23%) or 2.04% (95% CI: 0.88%, 3.20%) of YLLs could be attributed to PM 2.5 exposures higher than the Chinese or WHO guidelines, respectively. This study suggests that people might live longer by controlling daily PM 2.5 concentration and highlights the need to adopt stricter standards in China. • We estimated the life time gain by attaining daily PM 2.5 standards. • Life time might increase by 0.39 years for each death by attaining WHO's guideline. • Up to 2.04% of YLL could be ascribed to PM 2.5 exposure higher than WHO's guideline. • More ambitious target for PM 2.5 control should be employed to improve public health. [ABSTRACT FROM AUTHOR]

Background Daily mean concentration cannot fully address the hourly variations of air pollution within one day. As such, we proposed a new indicator, daily exceedance concentration hours (DECH), to explore the acute cardiovascular effects of ambient PM 2.5 (particles with aerodynamic diameters less than 2.5 μm). The DECH in PM 2.5 was defined as daily total concentration-hours > 25 μg/m 3 . Methods A generalized additive model with a quasi-Poisson link was applied to estimate the associations between day-to-day variation in PM 2.5 DECH and day-to-day variation in cardiovascular mortality in six subtropical cities in Guangdong Province, China. Results The analysis revealed significant associations between PM 2.5 DECHs and cardiovascular mortality. A 500 μg/m 3 ∗ h increase in PM 2.5 DECHs at lag 03 was associated with an increase of 4.55% (95% confidence interval (CI): 3.59%, 5.52%) in cardiovascular mortality, 4.45% (95% CI: 2.81%, 6.12%) in ischemic cardiovascular mortality, 5.02% (95% CI: 3.41%, 6.65%) in cerebrovascular mortality, and 3.00% (95% CI: 1.13%, 4.90%) in acute myocardial infarction mortality. We further observed a greater mortality burden using PM 2.5 DECHs than daily mean PM 2.5 (6478 (95% CI: 5071, 7917) VS 5136 (95% CI: 3990, 6305)). Conclusion This study reveals that PM 2.5 DECH is one important exposure indicator of ambient PM 2.5 to measure its cardiovascular mortality effects in Pearl River Delta region; and that using daily mean concentration could under-estimate the mortality burden compared with this new indicator. [ABSTRACT FROM AUTHOR]

Compared with daily mean concentration of air pollution, hourly peak concentration may be more directly relevant to the acute health effects due to the high concentration levels, however, few have analyzed the acute mortality effects of hourly peak levels of air pollution. We examined the associations of hourly peak concentration of fine particulate matter air pollution (PM 2.5 ) with mortality in six cities in Pearl River Delta, China. We used generalized additive Poisson models to examine the associations with adjustment for potential confounders in each city. We further applied random-effects meta-analyses to estimate the regional overall effects. We further estimated the mortality burden attributable to hourly peak and daily mean PM 2.5 . We observed significant associations between hourly peak PM 2.5 and mortality. Each 10 μg/m3 increase in 4-day averaged (lag 03 ) hourly peak PM 2.5 corresponded to a 0.9% [95% confidence interval (CI): 0.7%, 1.1%] increase in total mortality, 1.2% (95% CI: 1.0%, 1.5%) in cardiovascular mortality, and 0.7% (95% CI: 0.2%, 1.1%) in respiratory mortality. We observed a greater mortality burden using hourly peak PM 2.5 than daily mean PM 2.5 , with an estimated 12915 (95% CI: 9922, 15949) premature deaths attributable to hourly peak PM 2.5 , and 7951 (95% CI: 5067, 10890) to daily mean PM 2.5 in the Pearl River Delta (PRD) region during the study period. This study suggests that hourly peak PM 2.5 might be one important risk factor of mortality in PRD region of China; the finding provides important information for future air pollution management and epidemiological studies. [ABSTRACT FROM AUTHOR]

Background Epidemiological studies have reported significant association between ambient fine particulate matter air pollution (PM 2.5 ) and mortality, however, few studies have investigated the relationship of mortality with PM 2.5 and associated mortality burden in China, especially in a multicity setting. Methods We investigated the PM 2.5 -mortality association in six cities of the Pearl River Delta region from 2013 to 2015. We used generalized additive Poisson models incorporating penalized smoothing splines to control for temporal trend, temperature, and relative humidity. We applied meta-analyses using random-effects models to pool the effect estimates in the six cities. We also examined these associations in stratified analyses by sex, age group, education level and location of death. We further estimated the mortality burden (attributable fraction and attributable mortality) due to ambient PM 2.5 exposures. Results During the study period, a total of 316,305 deaths were recorded in the study area. The analysis revealed a significant association between PM 2.5 and mortality. Specifically, a 10 μg/m 3 increase in 4-day averaged (lag 03 ) PM 2.5 concentration corresponded to a 1.76% (95% confidence interval (CI): 1.47%, 2.06%) increase in total mortality, 2.19% (95% CI: 1.80%, 2.59%) in cardiovascular mortality, and 1.68% (95% CI: 1.00%, 2.37%) in respiratory mortality. The results were generally robust to model specifications and adjustment of gaseous air pollutants. We estimated that 0.56% (95% CI: 0.47%, 0.66%) and 3.79% (95% CI: 3.14%, 4.45%) of all-cause mortalities were attributable to PM 2.5 using China's and WHO's air quality standards as the reference, corresponding to 1661 (95% CI: 1379, 1946) and 11,176 (95% CI: 9261, 13,120) attributable premature mortalities, respectively. Conclusion This analysis adds to the growing body of evidence linking PM 2.5 with daily mortality, and mortality burdens, particularly in one Chinese region with high levels of air pollution. [ABSTRACT FROM AUTHOR]

In 2012, Chinese Environmental Bureau modified its National Ambient Air Quality Standards to include fine particulate matter (PM 2.5 ). Recent air pollution monitoring data shows that numerous locations have exceeded this standard, which may have resulted in avoidable adverse health effects. For example, among the 74 Chinese cities with PM 2.5 monitoring data in 2013, only three cities attained the annual air quality standard (35 μg/m 3 ). This study aimed to quantify the potential short- and long-term health benefits from achieving the Chinese ambient air quality standard and WHO’s air quality objectives. A generalized additive model was used to estimate the short-term association of mortality with changes in daily PM 2.5 concentrations, based on which we estimated the potential premature mortality reduction that would have been achieved during the period of 2012–2015 if the daily air quality standard had been met in Guangzhou, China; we also estimated the avoidable deaths if attaining the annual air quality standard using the relative risk obtained from a previous cohort study. During the study period, there were 160 days exceeding the national daily PM 2.5 standard (75 μg/m 3 ) in Guangzhou, and the annual average concentration (47.7 μg/m 3 ) was higher than the air quality standard of 35 μg/m 3 . Significant associations between PM 2.5 and mortality were observed. An increase of 10 μg/m 3 in PM 2.5 was associated with increases in daily death counts of 0.95% (95% CI: 0.56%, 1.34%) in natural mortality, 1.31% (95% CI: 0.75%, 1.87%) in cardiovascular mortality, and 1.06% (95% CI: 0.19%, 1.94%) in respiratory mortality. The health benefits of attaining the national daily air quality standard of PM 2.5 (75 μg/m 3 ) would have prevented 143 [95% confidence interval (CI): 84, 203] fewer natural deaths, including 84 (95% CI: 48, 121) fewer cardiovascular deaths and 27 (95% CI: 5, 49) fewer respiratory deaths. Had the annual PM 2.5 levels been reduced to 35 μg/m 3 , an estimated 3875 (95% CI: 1852, 6074) natural deaths, 2378 (95% CI: 800, 4230) cardiovascular deaths, and 227 (95% CI: -437, 1033) respiratory deaths could have been prevented. Even greater substantial mortality reductions could be achieved if the WHO’s air quality objectives were met. Our study suggests that air pollution is significantly associated with mortality in Guangzhou, and more stringent air quality standards would significantly reduce air pollution-related premature mortality. [ABSTRACT FROM AUTHOR]

Though increasing evidence supports significant association between particulate matter (PM) air pollution and stroke, it remains unclear what characteristics, such as particle size and chemical constituents, are responsible for this association. A time-series model with quasi-Poisson function was applied to assess the association of PM pollution with different particle sizes and chemical constituents with mortalities from ischemic and hemorrhagic strokes in Guangzhou, China, we controlled for potential confounding factors in the model, such as temporal trends, day of the week, public holidays, meteorological factors and influenza epidemic. We found significant association between stroke mortality and various PM fractions, such as PM10, PM2.5 and PM1, with generally larger magnitudes for smaller particles. For the PM2.5 chemical constituents, we found that organic carbon (OC), elemental carbon (EC), sulfate, nitrate and ammonium were significantly associated with stroke mortality. The analysis for specific types of stroke suggested that it was hemorrhagic stroke, rather than ischemic stroke, that was significantly associated with PM pollution. Our study shows that various PM pollution fractions are associated with stroke mortality, and constituents primarily from combustion and secondary aerosols might be the harmful components of PM2.5 in Guangzhou, and this study suggests that PM pollution is more relevant to hemorrhagic stroke in the study area, however, more studies are warranted due to the underlying limitations of this study. [ABSTRACT FROM AUTHOR]