2014~2016年京津冀沿山城市空气质量首要污染物特征分析

对北京、保定、石家庄、邢台和邯郸这5个京津冀太行山沿山城市2014~2016年空气质量首要污染物进行分析,探讨其空间分布特征和时间变化趋势.结果表明,北京首要污染物由主到次为PM_2.5、O₃-8h、NO₂和PM₁₀,其他4个城市首要污染物排序为PM_2.5、PM₁₀、O₃-8h、NO₂、SO₂和CO.在空间分布上,各城市PM_2.5首要污染物天数比例3 a均值相当（53.3%~58.1%）,但从北向南,5个城市PM₁₀天数比例基本呈上升趋势,而O₃-8h反之.除邯郸PM_2.5首要污染物天数比例逐年明显下降外,其他4个城市的天数比例年际变化幅度较小;2016年石家庄、邢台和邯郸O₃-8h天数比例均显著上升.各城市PM_2.5和O₃-8h首要污染物天数月变化曲线分别呈"W"型和"倒U"型,PM₁₀首要污染物天数在3~5月出现明显高值区.从良至严重污染,各城市PM_2.5和PM₁₀首要污染物天数比例之和随空气质量级别逐级递增,其中PM₁₀天数比例逐级下降,而PM_2.5表现相反;O₃-8h首要污染物天基本出现在良至中度污染级别,且总体上逐级下降;NO₂仅在良级天有较高的天数比例贡献.

Characteristics of Primary Pollutants of Air Quality in Cities Along the Taihang Mountains in Beijing-Tianjin-Hebei Region During 2014-2016

Primary pollutants of air quality in Beijing, Baoding, Shijiazhuang, Xingtai, and Handan cities along the Taihang Mountains were analyzed to investigate their spatial distribution characteristics and temporal variation trends during 2014-2016. The results showed that the primary pollutants were ranked as PM_2.5, O₃-8h, NO₂ and PM₁₀ from most to least important in Beijing, and PM_2.5, PM₁₀, O₃-8h, NO₂, SO₂ and CO in the other four cities. Three-year average percentages of days with PM_2.5 as the primary pollutant in each city were similar (53.3%-58.1%), however, percentages of days with PM₁₀ as primary pollutant increased, while percentages of O₃-8h decreased basically, from north to south. Except for Handan with a significant descending trend, percentages of days with PM_2.5 as primary pollutant varied slightly in the other four cities during the study period, and percentages of O₃-8h of Shijiazhuang, Xingtai and Handan increased significantly in 2016. Percentages of NO₂ slightly declined year by year in Beijing, and the other four cities mainly showed the opposite trend. Monthly variation curves of days with PM_2.5 and O₃-8h as primary pollutants showed "W" and "inverted U" types respectively, while the high value interval of days with PM₁₀ as primary pollutant occurred between March and May. With the exception of Beijing, peak of monthly variation curves for days with NO₂ as the primary pollutant was occurred in October in the other four cities. From "moderate" to "hazardous" levels for air quality, the percentages of days with PM_2.5 and/or PM₁₀ as primary pollutants increased level by level, with percentages of PM₁₀ trending downwards and PM_2.5 upwards. Meanwhile, days with O₃-8h as the primary pollutant mostly appeared in the range between "moderate" and "unhealthy" levels, and NO₂ was only prominent in "moderate" level.