Dataset Information

Understanding the Rising Phase of the PM_2.5 Concentration Evolution in Large China Cities.

ABSTRACT: Long-term air quality observations are seldom analyzed from a dynamic view. This study analyzed fine particulate matter (PM_2.5) pollution processes using long-term PM_2.5 observations in three Chinese cities. Pollution processes were defined as linearly growing PM_2.5 concentrations following the criteria of coefficient of determination R²?>?0.8 and duration time T???18?hrs. The linear slopes quantitatively measured pollution levels by PM_2.5 concentrations rising rates (PMRR, ?g/(m³·hr)). The 741, 210 and 193 pollution processes were filtered out, respectively, in Beijing (BJ), Shanghai (SH), and Guangzhou (GZ). Then the relationships between PMRR and wind speed, wind direction, 24-hr backward points, gaseous pollutants (CO, NO₂ and SO₂) concentrations, and regional PM_2.5 levels were studied. Inverse relationships existed between PMRR and wind speed. The wind directions and 24-hr backward points converged in specific directions indicating long-range transport. Gaseous pollutants concentrations increased at variable rates in the three cities with growing PMRR values. PM_2.5 levels at the upwind regions of BJ and SH increased at high PMRRs. Regional transport dominated the PM_2.5 pollution processes of SH. In BJ, both local contributions and regional transport increased during high-PMRR pollution processes. In GZ, PM_2.5 pollution processes were mainly caused by local emissions.

SUBMITTER: Lv B

PROVIDER: S-EPMC5404509 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

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Understanding the Rising Phase of the PM2.5 Concentration Evolution in Large China Cities.

Lv Baolei B Cai Jun J Xu Bing B Bai Yuqi Y

Scientific reports 20170425

Long-term air quality observations are seldom analyzed from a dynamic view. This study analyzed fine particulate matter (PM2.5) pollution processes using long-term PM2.5 observations in three Chinese cities. Pollution processes were defined as linearly growing PM2.5 concentrations following the criteria of coefficient of determination R2 > 0.8 and duration time T ≥ 18 hrs. The linear slopes quantitatively measured pollution levels by PM2.5 c ...[more]

PMID: 28440282

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Project description:In recent years, PM2.5 and O3 have been the two main pollutants affecting public health in China, but the interaction of the two pollutants on human health remains unclear. A two-stage analytical approach was used to investigate the relationships of PM2.5-O3 co-pollution with nonaccidental, cardiovascular, and respiratory mortality levels across 14 cities in China. We first utilized a generalized additive model (GAM) to determine the city-specific associations of PM2.5 and O3 with daily mortality. The associations were then combined at the national and regional levels using meta-analysis. To investigate the potential interactions between the two pollutants and cause-specific mortality, we performed stratified analyses by co-pollutant exposure levels and the synergy index (SI) (SI > 1 indicates a synergistic interaction). The effect of changes in the two pollutants' concentrations (in 10 μg/m3 increases) on mortality was assessed. The stratification analysis results suggested that each 10 μg/m3 increase in PM2.5 at lag0-1 (lag01) in the low, moderate, and high strata of the O3 concentrations increased nonaccidental mortality by 0.07% (95% confidence interval: -0.03%, 0.17%), 0.33% (0.13%, 0.53%), and 0.68% (0.30%, 1.06%), respectively, with significant between-group differences (p < 0.001). Moreover, each 10 μg/m3 increase in O3 (lag01) in the low, moderate, and high strata of the PM2.5 concentrations increased nonaccidental mortality by 0.15% (-0.06%, 0.36%), 0.53% (0.19%, 0.87%), and 0.75% (0.14%, 1.36%), respectively, with significant between-group differences (p < 0.001). We also found substantial synergistic interactions between the two pollutants and nonaccidental, cardiovascular, and respiratory mortality levels, with SI values of 1.48, 1.51, and 1.33, respectively. Additionally, a subgroup analysis revealed that the interaction of these two pollutants on nonaccidental mortality were greater in South China compared to elsewhere, and during the warm season compared to during the cold season. Our findings suggested that the simultaneous control of PM2.5 and O3 within the context of combined air pollution could significantly decrease the disease risk, especially in southern China and during the warm season.

Dataset Information

Understanding the Rising Phase of the PM_2.5 Concentration Evolution in Large China Cities.

Publications

Understanding the Rising Phase of the PM<sub>2.5</sub> Concentration Evolution in Large China Cities.

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