【摘要】 农业源PM_2.5排放对大气PM_2.5和灰霾形成有重要影响。为探索畜禽养殖场PM_2.5排放对大气PM_2.5浓度和化学成分的作用机理,选择山西省太原市尖草坪区一育肥猪场为研究地点,使用固定式PM_2.5在线检测仪和大气PM_2.5实时监测仪于2017年7月13日～19日连续测量猪舍内外PM_2.5和PM_2.5质量浓度,同时记录气温和相对湿度;使用中流量大气PM_2.5采样器采集细颗粒样品并用离子色谱仪测量样品中NH₄⁺、NO₃^-和SO₄^2- 含量,结果显示:（1）猪舍外和猪舍内PM_2.524 h平均浓度分别为5. 37±0. 35 mg/m³和7. 49±0. 37 mg/m³,它们的小时浓度变化趋势一致,白天PM_2.5平均浓度低于夜间;（2）猪舍外和猪舍内大气PM_2.5浓度24h平均值分别为93±18μg/m³和81±6μg/m³,它们白天的波动范围相似,但夜间猪舍外大气PM_2.5浓度显著增大;（3）猪舍内外大气PM_2.5中NH₄⁺含量与NO₃^-、SO₄^2- 以及空气中PM_2.5浓度显著相关,表明猪舍内PM_2.5对大气PM_2.5中二次气溶胶的形成有一定贡献,可以增大养殖场周围大气PM_2.5质量浓度。由于猪舍内外PM_2.5浓度变化与空气中PM_2.5浓度呈相反关系,且PM_2.5和PM_2.5质量浓度均为夜间大于白天,PM_2.5/NH₄⁺比值与温湿度也存在较好的相关性,说明光照、气温、相对湿度等对PM_2.5转化为二次气溶胶影响很大,养殖场PM_2.5排放对大气PM_{2. 5}质量浓度的作用机理仍需深入探索。更多还原

【Abstract】 NH₃ emissions from agricultural sources make an important impact on the formation of atmospheric PM_2.5 and haze.Herein,the aim is to investigate the effects of PM_2.5 emissions from a livestock farm on atmospheric PM_2.5 concentration and chemical composition and explore the affecting mechanisms. At first,a typical fattening pig farm located in Jiancaoping District,Taiyuan city,China was selected as the study site.Then,the PM_2.5 and PM_2.5 concentrations both inside and outside the pig house as well as air temperature and relative humidity were continuously measured on July 13 to 19,2017 by using a fixed PM_2.5 on-line instrument and a real-time PM_2.5 monitor.And the atmospheric PM_2.5 samples were collected each day using a medium-flow PM_2.5 sampler and the contents of NH₄⁺,NO₃^-and SO₄^2- in them were determined using an ion chromatograph.Results showed that:（ 1） The daily mean concentrations of PM_2.5 outside and inside the pig house were 5. 37±0. 35 mg·m^-3 and 7. 4± 0. 37 mg·m^-3,respectively,with the same alteration trend for the hourly levels and with higher concentrations at nighttime than those at daytime;（ 2） The daily mean concentrations of atmospheric PM_2.5 outside and inside the pig house were 93± 18 μg·m^-3 and 81± 6 μg·m^-3,respectively,with similar fluctuation range at daytime and with an increase at nighttime;（ 3） There was a significant correlation between the levels of NH₄⁺and that of NO₃^-and SO₄^2- in PM_2.5 and between NH₄⁺and airborne PM_2.5 in the pig house no matter inside or outside,indicating that the concentration change of ammonium salt in atmospheric PM_2.5 should be closely related to the levels of PM_2.5 in the air.Regarding the content of atmospheric PM_2.5 is opposite to that of PM_2.5 inside and outside the pig house,the concentrations of PM_2.5 and PM_2.5 are larger at nighttime than at daytime,and a good relation of the ratio value of PM_2.5/NH₄⁺with temperature and relative humidity,it is concluded that PM_2.5 from the pig house contributes a lot to formation of secondary aerosols in PM_2.5,which is greatly influenced by light,temperature,and relative humidity.It is suggested that the affecting mechanism of PM_2.5 emissions from livestock farms on mass concentrations of PM_2.5 in the surrounding atmosphere is needed to further study.更多还原