哈尔滨大气颗粒物PM_(2.5)中微塑料的赋存特征及基于PMF法的来源解析

Property characteristics of PM_(2.5) and source analysis based on PMF method in Harbin

微塑料具有尺寸小、性质稳定、难以分解及广泛存在于自然环境中的特点.为探究大气颗粒物PM_(2.5)中微塑料赋存特征及潜在来源,以北方城市哈尔滨为研究区,通过采集悬浮空气样品中的PM_(2.5)及微塑料,利用体式显微镜、傅里叶变换红外光谱仪、扫描电镜等方法定性定量地分析了大气颗粒物中微塑料的丰度、外观特征以及类型,并分析了其潜在来源.结果表明,哈尔滨取暖期PM_(2.5)质量浓度变化较大,采样期间PM_(2.5)最大值为305μg·m^(-3)、最小值为15μg·m^(-3).PM_(2.5)中微塑料丰度变化与PM_(2.5)质量浓度变化呈正相关,PM_(2.5)中微塑料最大值为17个·m^(-3)、最小值为3个·m^(-3).空气质量越好,单位质量的PM_(2.5)中的微塑料个数越多,而空气污染越严重,单位质量的PM_(2.5)中的微塑料个数反而越少.PM_(2.5)中微塑料颜色主要为黑色和透明,少数彩色,但空气质量较好时彩色微塑料占比较多,与人类活动直接相关.纤维状的微塑料占主导地位,碎片状和薄膜状较少.采样区域样品中存在聚对苯二甲酸乙二醇酯(PET)、聚酯(PP)、聚氯乙烯(PVC)、聚苯乙烯(PS),且在聚对苯二甲酸乙二醇酯(PET)、聚酯(PP)占比较高.根据微塑料的形状、类型,利用PMF法确定了采样点微塑料的潜在来源,共解析出4种因子,其中一种因子以纤维状微塑料贡献率较高为特征,检测到主要成分为PET、PP,推断其潜在来源是服装;两种因子中碎片状微塑料贡献率较高,检测到主要成分为PP、PVC,主要来自塑料包装袋以及零件;另一种因子中薄膜状微塑料贡献率较高,检测到主要成分为PP、PS,推断其潜在来源则是农业地膜.

Microplastics are tiny in size,stable in nature,difficult to degrade,and abundant in nature.This study used Harbin,a northern city,as the study area to investigate the characteristics and potential sources of microplastics in atmospheric particulate matter PM_(2.5).It analyzed the abundance,appearance,and types of microplastics in atmospheric particulate matter qualitatively and quantitatively by collecting PM_(2.5) and microplastics in suspended air samples using a body microscope,Fourier transform infrared spectrometer,and scanning electron microscope.The findings revealed that the PM_(2.5) mass concentration in Harbin varied significantly during the heating season,reaching a high of 305 g·m^(-3) and a minimum of 15 g·m^(-3).The change in microplastic abundance in PM_(2.5) was positively correlated with the change in PM_(2.5) mass concentration,with a maximum value of 17 microplastics·m^(-3) and a minimum value of 3 microplastics·m^(-3) in PM_(2.5).In locations with better air quality,there are more microplastics per unit mass of PM_(2.5),whereas in conditions with lower air quality,there are less microplastics per unit mass of PM_(2.5).The majority of microplastics in PM_(2.5) are black and clear,with a few colorful ones,however,colored microplastics are more prevalent when air quality is excellent,which is directly tied to human activity.Fibrous microplastics predominated,with fewer fragmented and film-like microplastics.The samples contained polyethylene terephthalate(PET),polyester(PP),polyvinyl chloride(PVC),and polystyrene(PS),with a larger percentage of polyethylene terephthalate(PET)and polyester(PP).The PMF approach was used to identify probable sources of microplastics at the sample locations based on the form and type of the microplastics.In total,four factors were resolved.One factor had a high contribution of film-like microplastics,and the main components were detected as PET and PP,predominantly from clothing.Two factors had a high contribution of fragmented microplastics,and the main components were detected as PP and PVC,primarily from plastic packaging bags and parts.One factor had a high contribution of film-like microplastics,and the main components were identified as PP and PS,with agricultural mulch as a possible source.