2002-2005年上海市两监测点大气污染物变化规律

张莉君; 许慧慧; 施烨闻; 东春阳; 郭雁飞

摘要:

目的了解上海市两监测点大气污染物 SO₂、NO₂和 PM₁₀的时空变化规律。

方法收集 2002-2005年上海市两个环境监测点(A监测点位于市区, B监测点位于郊区)SO₂、NO₂和 PM₁₀的日均浓度, 用 SPSS 11.5软件, 采用Wilcoxon秩和检验和 Kruskal-Wallis 检验分析大气污染物月、季度和年浓度变化规律, 用 Spearman秩相关分析两监测点污染物之间的相关性。

结果在 1、2、3、5、9、10月份, B监测点 SO₂平均浓度均高于 A监测点(P <0.01或 P<0.05);NO₂月平均浓度在 7、12月份 B监测点高于 A监测点(P < 0.01); 除 2、3、5月份外, 其他月份 PM₁₀的平均浓度 B监测点均高于 A监测点(P < 0.01或 P < 0.05); A、B两监测点大气 SO₂、NO₂和 PM₁₀浓度的月份变化均呈" V" 型分布。在春、秋、冬 3季, B监测点 SO₂平均浓度高于 A监测点(P < 0.01), 夏季 NO₂平均浓度 B监测点高于 A监测点(P < 0.05), PM₁₀则 4个季节中 B监测点的平均浓度均高于 A监测点(P < 0.01)。3种污染物的季节变化多表现为冬季严重, 夏季轻的特点。从年变化趋势来看, A监测点的 SO₂污染呈逐年上升的趋势, NO₂和 PM₁₀则变化不显著; B监测点的 NO₂浓度变化趋势相对稳定, SO₂和 PM₁₀则在地方政府的环境综合整治下有所下降。用国家《环境空气质量标准》 (GB 3095-1996)评价, 两监测点 3种污染物均存在超标问题, 其中超标最严重的是 PM₁₀, 其次是 SO₂, 且 B监测点超标问题较 A监测点突出。两监测点 3种污染物浓度之间有弱相关性, A监测点各污染物间的相关性高于 B监测点, 尤其是 NO₂和 PM₁₀的相关性较高。

结论两监测点空气质量尚可, B监测点大气 SO₂、NO₂和 PM₁₀污染较 A监测点严重, 3种污染物浓度之间有弱相关性。

Abstract:

Objective To analyze the time-spatial variation of air pollutants, i.e. SO₂, NO₂ and PM₁₀, at two monitoring spots of Shanghai from 2002 to 2005.

Methods Daily average air SO₂, NO₂ and PM₁₀ levels during 2002 through 2005 from two environmental monitoring spots (spot A in urban district and spot B in suburb district) of Shanghai were collected. The variation of pollutant levels by month, season and year was analyzed by Wilcoxon rank sum test and Kruskal-Wallis test, and the correlation between pollutants in the two sites was analyzed by Spearman rank correlation analysis using SPSS 11.5.

Results The monthly SO₂ level in spot B was higher than that in spot A in January, February, March, May, September, and October (P < 0.01 or P < 0.05). The monthly NO₂ level in spot B was higher than that in spot A in July and December (P < 0.01). Except February, March and May, the monthly PM₁₀ level in spot B was higher than that in spot A (P < 0.01 or P < 0.05). The variation of monthly SO₂, NO₂ and PM₁₀ levels from January to December showed a "V" shape fluctuation in both spots. The seasonal level of SO₂ in spot B was higher than that in spot A in spring, autumn and winter (P < 0.01). The seasonal level of NO₂ in spot B was higher than that in spot A in summer (P < 0.05). The seasonal level of PM₁₀ in spot B was all higher than that in spot A (P < 0.01). Almost all air pollutant levels in the two spots were higher in winter and lower in summer. From 2002 through 2005, in spot A, air SO₂ level was ascending year after year, variations of air PM₁₀ and NO₂ was not distinct. As for spot B, variations of air NO₂ was not distinct, but air SO₂ and PM₁₀ levels were decreasing because of the comprehensive treatment of local government. According to Ambient Air Quality Standard, GB 3095-1996, the SO₂, NO₂ and PM₁₀ levels of the two monitoring spots both exceeded limits, especially PM₁₀ followed by SO₂, whereas problems in spot B was more serious than that in spot A. There was a weak correlation among the levels of the three air pollutants, which was more stronger in spot A than in spot B, especially the correlation between NO₂ and PM₁₀.

Conclusion Generally, the air quality in the two spots was acceptable. The air pollution in site B was more serious than that in site A, and a weak correlation was observed among air pollutants SO₂, NO₂ and PM₁₀.

2002-2005年上海市两监测点大气污染物变化规律

Air Pollutants Changes at Two Monitoring Spots of Shanghai, 2002-2005