Hsu Yu-Mei, Clair Thomas A
a Wood Buffalo Environmental Association , Fort McMurray , Alberta , Canada.
J Air Waste Manag Assoc. 2015 Apr;65(4):423-35. doi: 10.1080/10962247.2014.1001088.
The ambient ion monitor-ion chromatography (AIM-IC) system, which provides hourly measurements of the main chemical components of PM2.5 (particulate matter with an aerodynamic diameter<2.5 μm) and its precursor gases, was evaluated and deployed from May to July 2011 and April to December 2013 in the Athabasca Oil Sands Region (AOSR) of northeastern Alberta, Canada. The collection efficiencies for the gas-phase SO2 and HNO3 using the cellulose membrane were 96% and 100%, respectively, and the collection efficiency of NH3 using the nylon membrane was 100%. The AIM-IC was compared with a collocated annular denuder sampling system (ADSS) and a Federal Reference Method (FRM) Partisol PM2.5 sampler. The correlation coefficients of SO4(2-) concentrations between the AIM-IC and ADSS and between the AIM-IC and the Partisol PM2.5 sampler were 0.98 and 0.95, respectively. The comparisons also showed no statistically significant difference between the measurement sets, suggesting that the AIM-IC measurements of the PM2.5 chemical composition are comparable to the ADSS and Partisol PM2.5 methods. NH3 concentration in the summer (mean±standard deviation, 1.9±0.7 µg m(-3)) was higher than in the winter (1.3±0.9 µg m(-3)). HNO3 and NO3- concentrations were generally low in the AOSR, and especially in the winter months. NH4+ (0.94±0.96 µg m(-3)) and SO4(2-) (0.58±0.93 µg m(-3)) were the major ionic species of PM2.5. Direct SO2 emissions from oil sands processing operations influenced ambient particulate NH4+ and SO4(2-) values, with hourly concentrations of NH4+ and SO4(2-) measured downwind (~30 km away from the stack) at 10 and 28 µg m(-3). During the regional forest fire event in 2011, high concentrations of NO3-, NH4+, HNO3, NH3, and PM2.5 were observed and the corresponding maximum hourly concentrations were 31, 15, 9.6, 89, and >450 (the upper limit of PM2.5 measurement) µg m(-3), suggesting the formation of NH4NO3.
The AOSR in Canada is one of the most scrutinized industrial regions in the developed world due to the extent of oil extraction activities. Because of this, it is important to accurately assess the effect of these operations on regional air quality. In this study, we compare a new analytical approach, AIM-IC, with more standard analytical approaches to understand how local anthropogenic and nonanthropogenic sources (e.g., forest fires) impact regional air quality. With this approach, we also better characterize PM2.5 composition and its precursor gases to understand secondary aerosol formation mechanisms and to better identify possible control techniques if needed.
环境离子监测仪 - 离子色谱法（AIM - IC）系统可每小时测量一次PM2.5（空气动力学直径小于2.5微米的颗粒物）的主要化学成分及其前驱气体。该系统于2011年5月至7月以及2013年4月至12月在加拿大艾伯塔省东北部的阿萨巴斯卡油砂地区（AOSR）进行了评估和部署。使用纤维素膜对气相SO₂和HNO₃的采集效率分别为96%和100%，使用尼龙膜对NH₃的采集效率为100%。将AIM - IC与并置的环形扩散管采样系统（ADSS）以及联邦参考方法（FRM）Partisol PM2.5采样器进行了比较。AIM - IC与ADSS之间以及AIM - IC与Partisol PM2.5采样器之间SO₄²⁻浓度的相关系数分别为0.98和0.95。比较结果还表明测量值之间无统计学显著差异，这表明AIM - IC对PM2.5化学成分的测量结果与ADSS和Partisol PM2.5方法具有可比性。夏季的NH₃浓度（平均值±标准差，1.9±0.7微克/立方米）高于冬季（1.3±0.9微克/立方米）。AOSR地区的HNO₃和NO₃⁻浓度总体较低，尤其是在冬季月份。NH₄⁺（0.94±0.96微克/立方米）和SO₄²⁻（0.58±0.93微克/立方米）是PM2.5的主要离子成分。油砂加工操作产生的直接SO₂排放影响了环境颗粒物中NH₄⁺和SO₄²⁻的值，在顺风方向（距离烟囱约30公里处）每小时测量的NH₄⁺和SO₄²⁻浓度分别为10和28微克/立方米。在2011年的区域森林火灾事件中，观测到高浓度的NO₃⁻、NH₄⁺、HNO₃、NH₃和PM2.5，相应的每小时最大浓度分别为31、15、9.6、89和>450（PM2.5测量上限）微克/立方米，这表明形成了NH₄NO₃。
由于石油开采活动的规模，加拿大的AOSR是发达国家中受审查最多的工业区之一。因此，准确评估这些作业对区域空气质量的影响非常重要。在本研究中，我们将一种新的分析方法AIM - IC与更标准的分析方法进行比较，以了解当地人为和非人为来源（如森林火灾）如何影响区域空气质量。通过这种方法，我们还能更好地表征PM2.5的成分及其前驱气体，以了解二次气溶胶的形成机制，并在需要时更好地确定可能的控制技术。
