A Decade of Aerosol and Gas Precursor Chemical Characterization at Mt. Lemmon, Arizona (1992 to 2002)
A Decade of Aerosol and Gas Precursor Chemical Characterization at Mt. Lemmon, Arizona (1992 to 2002)
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DOI：
10.2151/jmsj.84.653
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发表时间：
2006-08
影响因子：
3.1
通讯作者：
R. Matichuk;B. Barbaris;E. Betterton;M. Hori;Naoto Murao;S. Ohta;D. Ward
中科院分区：
文献类型：
--
作者：
R. Matichuk;B. Barbaris;E. Betterton;M. Hori;Naoto Murao;S. Ohta;D. Ward
气溶胶（PM 2.0），和相关的前体气体已连续监测山。莱蒙（2791米ASL），亚利桑那州，自1992年9月。长达一个月的样本收集在过滤器和化学分析，导致长达十年的记录，超过100个数据点，为每个物种-其中最长的此类记录目前可用。测定了SO2 - 4、NO - 3、Cl -、NH + 4、Ca 2+、Mg 2+、K +、Na +、元素碳（EC）、有机碳（OC）、NH3（g）、SO2（g）、HCl（g）和HNO 3（g）等。这些数据揭示了长期趋势、季节变化和物种之间的相关性。PM2.0（1.48 μg m-3，年平均）主要由SO24-（49% w/w）、NH 4+（16% w/w）、EC（11% w/w）和OC（22% w/w）组成。平均SO2 - 4 /NH + 4当量比为1：1，表明完全中和。PM2.0中位数为1.33 μg m-3（范围= 0.17-4.32 μg m-3）。中位EC为0.14 μg m-3（0.01-0.76），中位OC为0.29 μg m-3（0.03-1.33）。除SO2 - 4、SO2（g）、NH + 4和NH3（g）外，所有种类的年平均趋势似乎都在增加，但有些趋势可能不具有统计学意义。SO2（g）和SO2 - 4的长期下降趋势反映了过去十年中实施的源控制，而HNO 3（g）一直在增加，可能是由于该地区人口增长导致的NOx排放量增加。农业用地向城市用地的转换可能导致NH3（g）的减少。EC（5.2 ± 2.7ng m-3 y-1）和EC/OC（1.5 ± 0.75）× 10 - 2 y-1）的年变化趋势均为正趋势，但OC的年变化趋势不明显。似乎有一个重要的OC的第二来源，推测来自生物烃的光氧化。计算的年平均消光系数没有明显的变化趋势，但计算的单次散射消光系数（ω）可能在下降（-1. 5 ± 1. 1 x 10 - 3 y-1），这可能是由于与森林火灾和/或化石燃料燃烧有关的EC增加造成的。取决于临界单次散射的绝对值，气溶胶可能已经是一个净吸收体，或者如果目前的趋势继续下去，到世纪末才可能成为一个净吸收体。
Aerosols (PM 2.0 ), and associated precursor gases have been continuously monitored at Mt. Lemmon (2791 m ASL), Arizona, since September 1992. Month-long samples are collected on filters and chemically analyzed resulting in a decade-long record with over 100 data points for each species-among the longest such records currently available. The species determined include SO 2- 4 , NO - 3 , Cl - , NH + 4 , Ca 2+ , Mg 2+ , K + , Na + , elemental carbon (EC), organic carbon (OC), NH 3 (g), SO 2 (g), HCl(g) and HNO 3 (g). The data reveal long-term trends, seasonal variations, and correlations between species. PM 2.0 (1.48 μg m -3 , annual mean) is mainly comprised of SO 2- 4 (49% w/w), NH + 4 (16%), EC (11%) and OC (22%). The mean SO 2- 4 /NH + 4 equivalent ratio is 1:1 suggesting complete neutralization. Median PM 2.0 was 1.33 μg m -3 (range = 0.17-4.32 μg m -3 ). Median EC was 0.14 μg m -3 (0.01-0.76), and median OC was 0.29 μg m -3 (0.03-1.33). The annual mean trends of all species, with the exception of SO 2- 4 , SO 2 (g), NH + 4 and NH 3 (g), appear to be increasing, but some trends may not be statistically significant. Long-term decreasing trends in SO 2 (g) and SO 2- 4 , reflect source controls implemented over the past decade, whereas HNO 3 (g) has been increasing, possibly due to increased NO x emissions associated with population growth in the region. The associated conversion of agricultural land to urban use might be leading to a decrease in NH 3 (g). Annual trends for EC (5.2 ± 2.7 ng m -3 y -1 ) and EC/OC ((1.5 ± 0.75) × 10 -2 y -1 ) appear to be positive and significant, but there is no significant annual OC trend. There appears to be a significant secondary source of OC, presumably derived from photoxidation of biogenic hydrocarbons. There is no significant trend in the calculated annual mean extinction coefficient but the calculated single scattering albedo (ω) may be decreasing (-1.5 ± 1.1 x 10 -3 y -1 ), possibly caused by increasing EC associated with forest fires and/or fossil fuel combustion. Depending on the value of the critical single scattering albedo, the aerosol might already be a net absorber, or it might only become so by the end of the century if current trends continue.