北京市传统春节假期空气质量特征研究

利用2013~2020年北京市传统春节假期期间主要污染物浓度、PM_2.5主要离子组分浓度及气象数据,研究近年烟花爆竹集中燃放对北京市空气质量的影响.结果表明,自2018年北京市加强对烟花爆竹燃放的管控后,空气质量显著改善,其中2019年传统春节假期中共7个优良天,占比达87.5%,且未出现中度及以上级别污染天;近3年除夕期间的PM_2.5峰值浓度显著降低,与近8年最高值相比(2016年699μg/m³),降幅分别为61.1%、74.7%和71.4%.此外,一方面,近年除夕期间SO₂、PM₁₀和PM_2.5浓度突增倍数显著降低,由2013年的1.31、1.37和0.92降低至2020年的0.08、0.14和0.02.另一方面,与烟花爆竹相关的一次离子组分浓度增长倍数及对PM_2.5及其组分的贡献率逐年降低,说明近年烟花爆竹的集中燃放对空气质量的影响缩减明显.2020年传统春节假期期间,不利的气象条件使烟花爆竹燃放污染无法完全消散,同时加剧本地污染物积累和区域污染物输送,导致出现连续3d的重污染过程.因此,严苛的禁限放措施、有利的气象条件、低水平的周边区域污染物浓度对北京市传统春节假期的空气质量至关重要.

A study on the air quality in Beijing during the Spring Festival

This study investigated the influence of fireworks on air quality by using the concentrations of major pollutants and PM_2.5 components and meteorological conditions during the Spring Festival in Beijing from 2013 to 2020. The results suggest that air quality improved significantly due to strict control on fireworks since 2018. In particular, 87.5% (seven days) of the days during the 2019 Spring Festival achieved the good and excellent air quality standards, and no heavy polluted days occurred. The maximum PM_2.5 concentration during the New Year’s eve decreased sharply in recent three years, falling by 61.1%, 74.7% and 71.4%, respectively, compared to the highest concentration of 699μg/m³ in 2016. Besides, the sudden increase rates of SO₂, PM₁₀and PM_2.5 concentrations were reduced from 1.31, 1.37 and 0.92 in 2013 to 0.08, 0.14 and 0.02 in 2020. Further, the concentration of primary ion components from fireworks to PM_2.5 decreased significantly thus confirming the reduction in impact of fireworks on air quality in recent years. During the Spring Festival in 2020, adverse meteorological conditions prohibited fireworks pollution dispersion, and aggravated the local pollution accumulation and regional transport, resulting in three-day heavy pollution event. Therefore, the strict control of fireworks, optimal meteorological conditions, and low levels of pollution in the surrounding area are crucial to the air quality in Beijing during the Spring Festival.