Systematic Review and Meta-Analysis of the Association between Ambient Nitrogen Dioxide and Respiratory Disease in China.

Jiyao Sun,Andrew J Barnes,Jian Wang,Meng Wang,Dongyang He

doi:10.3390/ijerph14060646

Abstract

Objective: This study aimed to assess the quantitative effects of short-term exposure of ambient nitrogen dioxide (NO2) on respiratory disease (RD) mortality and RD hospital admission in China through systematic review and meta-analysis. Methods: A total of 29 publications were finally selected from searches in PubMed, Web of Science, CNKI and Wanfang databases. Generic inverse variance method was used to pool effect estimates. Pooled estimates were used to represent the increased risk of RD mortality and RD hospital admission per 10 μg/m3 increase in NO2 concentration. Results: Positive correlations were found between short-term NO2 exposure and RD in China. RD mortality and RD hospital admission respectively increased by 1.4% (95% CI: 1.1%, 1.7%) and 1.0% (95% CI: 0.5%, 1.5%) per 10 μg/m3 increase in NO2 concentration. Differences were observed across geographic regions of China. The risk of RD mortality due to NO2 was higher in the southern region (1.7%) than in the north (0.7%). Conclusions: Evidence was found that short-term exposure to NO2 was associated with an increased risk of RD mortality and RD hospital admission in China and these risks were more pronounced in the southern regions of the country, due in part to a larger proportion of elderly persons with increased susceptibility to NO2 in the population compared with the north.

Highlights

China has maintained a rapid rate of growth in its economy over the past three decades
Because no validated and standardized scales were recommended to assess the quality of time-series and case-crossover studies, we evaluated the quality of total 29 individual studies based on a scale from a related meta-analysis [35], which is composed of three items: respiratory disease (RD)
RD mortality and RD hospital admission were reported by 21 studies and eight studies, respectively (Table 1)

Summary

Introduction

China has maintained a rapid rate of growth in its economy over the past three decades. Ambient air pollution, which is composed of both solid particles and gaseous pollutants, has been demonstrated to be associated with various adverse effects on human health [2]. Automobile exhaust, industrial production has increased nitrogen dioxide (NO2 ) in the air [3]. Many epidemiological studies have shown strong evidence linking air pollutants, such as particulates, NO2 , sulfur dioxide (SO2 ), ozone with adverse health effects [3], it is still worth noting that NO2 which is a highly reactive, nitrogen-centred free radical, poorly water-soluble gas deposited peripherally in the lungs [5], probably more contribute to various respiratory diseases (RD), such as respiratory inflammation, responsiveness, infections and symptoms [6].

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Discussion

Conclusion