【摘要】 燃煤供暖被认为是中国北方采暖期大气污染的主要来源之一,因此国家计划以天然气替代燃煤作为取暖燃料以减轻大气污染。基于2016-2017年天津采暖期前后的空气质量监测数据,探究"煤改气"后城市大气污染物的时空分布特征及影响因素,为大气污染治理提供依据。研究表明,煤改气后天津采暖期主要大气污染物有PM_2.5、PM10和NO₂ 3种,CO日均质量浓度有超标现象发生,SO₂和O₃日均质量浓度均低于二级标准限值。与使用燃煤采暖时期相比,大气中SO₂、PM_2.5、PM₁₀和CO的日均质量浓度均有不同程度的降低,尤其是SO2浓度降幅高达70%,但NO₂质量浓度没有有效降低。从日变化特征来看,采暖期PM_2.5、PM10和CO的日变化规律受到了采暖活动影响,呈单峰单谷型的变化趋势。NO₂、SO₂和O₃的日变化规律与非采暖期相似,受采暖活动影响较小。由于受供暖和大气逆温层的影响,采暖期晚上至上午时段大气污染物（O3除外）的质量浓度远远高于非采暖期相同时段的质量浓度。天津大气污染物在非采暖期呈现出典型的"周末效应",但是在采暖期没有出现"周末效应"。冬季,周末白天人为活动较工作日更为活跃,与之相对应增加的城镇生活源可能是造成周末白天PM_2.5和PM₁₀质量浓度偏高及"周末效应"消失的主要原因。更多还原

【Abstract】 Coal-fired heating is regarded as an important factor that causes atmospheric pollution in the north of China in winter.Therefore, natural gas is used as a substitute for traditional coal combustion to reduce atmospheric pollution during the heating period. The concentrations datas of atmospheric pollutants in Tianjin in 2016 were collected in this work for discussing the spatial and temporal distribution and influence factors of atmospheric pollutants of Tianjin during the heating period after the "coal to gas" project. The results showed that the main non-attainment pollutants in Tianjin during the heating period were PM_2.5, PM₁₀ and NO₂.The 24-hour average concentrations of CO were higher than the ambient air quality standards of China for a few days during the heating period. The SO₂ and O₃ were attainments in Tianjin. The 24-hour average concentrations of PM_2.5, PM₁₀, CO, SO₂ after the "coal to gas" project reduced in varying degrees compared with using coal for heating. Especially, SO₂ concentrations decreased more than 70%. However, the NO₂ concentration did not decrease effectively. During the heating period, the typical diurnal variations of PM_2.5, PM10 and CO were affected by the heating, showing a trend of single peak and single valley type. The diurnal variations of NO₂, SO₂ and O₃ in the heating period were similar with that in non-heating period, and were less affected by the heating. Due to the influence of heating and atmospheric inversion layer, the atmospheric pollutants（excluding O₃） concentrations from evening to next morning during the heating period were marked higher than that in the same period of non-heating period. A "weekend effect" was showed during the non-heating period in Tianjin. However, no obvious "weekend effect" was observed during the heating period. In winter, people were more active on the daytime of weekends than on the daytime of workdays. The increased atmospheric pollutes from living may be the main reason for the high concentration of PM_2.5 and PM₁₀ during daytime of weekend and the disappearance of weekend effect.更多还原