Natural Resources and Environmental Studies Institute, Environmental Science and Engineering Programs, University of Northern British Columbia, Prince George, British Columbia, Canada.
J Air Waste Manag Assoc. 2013 Jul;63(7):773-87. doi: 10.1080/10962247.2013.789091.
This study investigates the development and application of a simple method to calculate annual and seasonal PM2.5 and PM10 background concentrations in small cities and rural areas. The Low Pollution Sectors and Conditions (LPSC) method is based on existing measured long-term data sets and is designed for locations where particulate matter (PM) monitors are only influenced by local anthropogenic emission sources from particular wind sectors. The LPSC method combines the analysis of measured hourly meteorological data, PM concentrations, and geographical emission source distributions. PM background levels emerge from measured data for specific wind conditions, where air parcel trajectories measured at a monitoring station are assumed to have passed over geographic sectors with negligible local emissions. Seasonal and annual background levels were estimated for two monitoring stations in Prince George, Canada, and the method was also applied to four other small cities (Burns Lake, Houston, Quesnel, Smithers) in northern British Columbia. The analysis showed reasonable background concentrations for both monitoring stations in Prince George, whereas annual PM10 background concentrations at two of the other locations and PM2.5 background concentrations at one other location were implausibly high. For those locations where the LPSC method was successful, annual background levels ranged between 1.8 +/- 0.1 microg/m3 and 2.5 +/- 0.1 microg/m3 for PM2.5 and between 6.3 +/- 0.3 microg/m3 and 8.5 +/- 0.3 microg/m3 for PM10. Precipitation effects and patterns of seasonal variability in the estimated background concentrations were detectable for all locations where the method was successful. Overall the method was dependent on the configuration of local geography and sources with respect to the monitoring location, and may fail at some locations and under some conditions. Where applicable, the LPSC method can provide a fast and cost-efficient way to estimate background PM concentrations for small cities in sparsely populated regions like northern British Columbia.
In rural areas like northern British Columbia, particulate matter (PM) monitoring stations are usually located close to emission sources and residential areas in order to assess the PM impact on human health. Thus there is a lack of accurate PM background concentration data that represent PM ambient concentrations in the absence of local emissions. The background calculation method developed in this study uses observed meteorological data as well as local source emission locations and provides annual, seasonal and precipitation-related PM background concentrations that are comparable to literature values for four out of six monitoring stations.
本研究旨在开发和应用一种简单的方法，以计算小城市和农村地区的年际和季节性 PM2.5 和 PM10 背景浓度。低污染区和条件 (LPSC) 方法基于现有的长期实测数据集，专为那些颗粒物 (PM) 监测站仅受特定风区局部人为排放源影响的地点设计。LPSC 方法结合了实测逐时气象数据、PM 浓度和地理排放源分布的分析。PM 背景水平源自特定风况下的实测数据，其中监测站测量的空气包裹轨迹被假定已通过地理区域，这些区域的本地排放可忽略不计。对加拿大乔治王子市的两个监测站进行了季节性和年度背景水平估计，该方法还应用于不列颠哥伦比亚省北部的另外四个小城市（伯恩斯湖、休斯顿、奎内尔、史密斯）。分析表明，乔治王子市的两个监测站的背景浓度都在合理范围内，而其他两个地点的年 PM10 背景浓度和另一个地点的 PM2.5 背景浓度高得离谱。对于 LPSC 方法成功的那些地点，PM2.5 的年背景水平范围在 1.8 +/- 0.1 微克/立方米至 2.5 +/- 0.1 微克/立方米之间，PM10 的年背景水平范围在 6.3 +/- 0.3 微克/立方米至 8.5 +/- 0.3 微克/立方米之间。对于所有成功应用该方法的地点，都可以检测到降水效应和估计背景浓度的季节性变化模式。总的来说，该方法取决于当地地理和污染源相对于监测地点的配置，并且可能在某些地点和某些条件下失效。在适用的情况下，LPSC 方法可为不列颠哥伦比亚省北部等人口稀少地区的小城市提供一种快速且具有成本效益的估算背景 PM 浓度的方法。
在像不列颠哥伦比亚省北部这样的农村地区，颗粒物 (PM) 监测站通常位于靠近排放源和居民区的地方，以便评估 PM 对人类健康的影响。因此，缺乏代表无本地排放时 PM 环境浓度的准确 PM 背景浓度数据。本研究开发的背景计算方法使用观测到的气象数据以及当地的源排放位置，并提供了年度、季节性和与降水相关的 PM 背景浓度，其中六个监测站中的四个监测站的浓度与文献值相当。
