治理后兰州市主城区大气污染物对居民非意外死亡及死亡负担的影响

Impact of air pollutants on non-accidental mortality and burden of death of residents after air pollution control in main urban districts of Lanzhou

  • 摘要:
    背景 大气污染是影响人群健康的主要环境危险因素。
    目的 了解大气污染治理后兰州市主要城区大气污染对居民非意外死亡和死亡负担的影响。
    方法 收集兰州市四个主要城区(城关区、七里河区、西固区、安宁区)大气污染治理前(2004-2011年)大气污染物SO2、NO2和PM10的监测数据和大气污染治理后(2014-2018年)大气污染物SO2、NO2、PM2.5、PM10、CO和O3的监测数据、气象数据和居民死因监测数据,统计非意外总死亡人数和大气污染物浓度;采用广义相加模型,控制时间趋势、季节效应、气象因素、星期几效应等因素,分析兰州市四个主要城区大气污染对居民非意外死亡的影响;利用泊松回归比例风险模型定量评价兰州市大气污染对居民的死亡负担。
    结果 兰州市四个城区2004-2011年SO2、NO2和PM10的年均质量浓度(简称为浓度)分别为61.58、45.47、154.97 μg·m-3。2014-2018年非意外总死亡人数为79 284人,平均每日非意外死亡人数为43人;SO2、NO2、PM2.5、PM10、CO和O3的年均浓度分别为21.58 μg·m-3、54.42 μg·m-3、52.67 μg·m-3、124.84 μg·m-3、1.41 mg·m-3和87.40 μg·m-3。兰州市大气污染治理后(2014-2018年)大气SO2、PM10日均浓度分别降低,NO2浓度有所升高。居民非意外死亡人数与SO2、NO2、PM10、O3、PM2.5和CO呈正相关,其中与SO2相关性最强(r=0.906),与NO2相关性最弱(r=0.048)。SO2、NO2对居民非意外死亡的影响在滞后2 d最大,其相对危险度分别为1.002 13(95% CI:1.001 35~1.002 90)和1.000 59(95% CI:1.000 17~1.001 02);PM10和PM2.5在当日达到最大,其相对危险度分别为1.00012(95% CI:1.000 04~1.00020)和1.00048(95% CI:1.000 17~1.000 79)。SO2、NO2、PM10和PM2.5浓度每增加10 μg·m-3,居民非意外死亡风险分别增加2.15%、0.59%、0.12%和0.49%。参照世界卫生组织提出的空气质量指导值,SO2、NO2、PM10和PM2.5污染所致的归因死亡人数(AM)分别为263、683、827、1 674人,其归因分值(AF)分别为2.56%、6.65%、8.06%和16.30%;参照GB 3095-2012《环境空气质量标准》规定的年均浓度二级限值,NO2、PM10和PM2.5污染所致的AM分别为683、434、698人,其AF分别为6.65%、4.22%和6.79%。
    结论 兰州市大气污染治理后大气污染物SO2、NO2、PM10和PM2.5仍可对居民非意外死亡造成影响,且SO2影响较大;在大气污染对居民的死亡负担影响中,PM2.5影响较大。

     

    Abstract:
    Background Air pollution is a major environmental risk factor that affects human health.
    Objective This study evaluates the impact of air pollution on non-accidental mortality and burden of death of residents in the main urban districts of Lanzhou after implementing air pollution control measures.
    Methods The monitoring data of air pollutants SO2, NO2, and PM10 from 2004 to 2011 (before air pollution control), and the monitoring data of air pollutants SO2, NO2, PM2.5, PM10, CO, and O3, meteorological variables, and death cause of residents from 2014 to 2018 (after air pollution control) in four main urban districts (Chengguan District, Qilihe District, Xigu District, and Anning District) of Lanzhou City were collected and used to calculate total non-accidental mortality and concentrations of air pollutants. The impact of air pollutants on non-accidental mortality of residents was analyzed by generalized additive models, after controlling time trends, seasonal effects, meteorological factors, day-of-the-week effect, and other factors. The burden of death attributed to air pollution was quantitatively evaluated by Poisson regression proportional risk models.
    Results From 2004 to 2011, the annual average concentrations of SO2, NO2, and PM10 in the four urban districts of Lanzhou were 61.58, 45.47, and 154.97μg·m-3, respectively. From 2014 to 2018, the total number of non-accidental mortality was 79 284, with an average of 43 nonaccidental deaths per day, and the average annual concentrations of SO2, NO2, PM2.5, PM10, CO, and O3 were 21.58μg·m-3, 54.42μg·m-3, 52.67μg·m-3, 124.84 μg·m-3, 1.41 mg·m-3, and 87.40 μg·m-3, respectively. After the air pollution control (2014-2018), the daily average concentrations of SO2 and PM10 decreased, while the concentration of NO2 increased. There was a positive correlation between non-accidental mortality and each of the selected six air pollutants, among which the correlation with SO2 was the strongest (r=0.906) and the correlation with NO2 was the weakest (r=0.048). The risk of non-accidental mortality attributed to SO2 and NO2 reached the highest value with a 2-day lag, and their relative risks were 1.002 13 (95% CI: 1.001 35-1.002 90) and 1.000 59 (95% CI: 1.000 17-1.001 02), respectively. The risk attributed to PM10 and PM2.5 reached the highest value on the current day, and their relative risks were 1.000 12 (95% CI: 1.000 04- 1.000 20) and 1.000 48 (95%CI: 1.00017-1.000 79), respectively. Each 10 μg·m-3 increase of SO2, NO2, PM10, and PM2.5 concentrations was associated with an increase in the risk of non-accidental mortality of residents by 2.15%, 0.59%, 0.12%, and 0.49%, respectively. According to the air quality guidelines proposed by the World Health Organization (WHO), the numbers of deaths attributable to SO2, NO2, PM10, and PM2.5 were 263, 683, 827, and 1 674, respectively, and their attributable fractions were 2.56%, 6.65%, 8.06%, and 16.30%, respectively. According to the second-level annual average concentration limits stipulated in the Ambient air quality standard (GB 3095-2012), the numbers of deaths attributable to NO2, PM10, and PM2.5 were 683, 434, and 698, respectively, and their attributable fractions were 6.65%, 4.22%, and 6.79%, respectively.
    Conclusion After implementing the air pollution control measures in Lanzhou, air pollutants SO2, NO2, PM10 and PM2.5 still have an impact on non-accidental mortality of residents, especially SO2, and on residents' burden of death, especially PM2.5.

     

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