冷凝湿度控制对微振荡天平监测细颗粒物性能的改进

Improvement of condensation humidity controller on PM_(2.5) monitoring performance of tapered element oscillating microbalance

为提高细颗粒物(PM2.5)测量的准确性,尝试采用一种新型的气溶胶冷凝湿度控制器(简称冷凝湿度控制器)作为微振荡天平法颗粒物监测仪(TEOM)的除湿方式,在广东大气超级监测站开展了TEOM自动监测(一台采用传统的加热除湿方式,记为TEOM1405;另一台采用冷凝湿度控制器除湿,记为TEOM1405+除湿)和手工监测结果的对比。结果表明,根据PM2.5日均值相关性的拟合结果,TEOM1405监测较手工监测结果总体偏低约13%,加装冷凝湿度控制器后,TEOM1405+除湿监测较手工监测结果总体偏低在5%以内。加装冷凝湿度控制器后,显著提高了PM2.5的监测准确性;在相对湿度较高、二次颗粒物生成量较少的大气环境中,TEOM1405+除湿系统对PM2.5的监测结果是可靠的,而且在降雨过程中监测结果更为稳定;但在相对湿度较高、且二次颗粒物生成量较多的大气环境中,其对PM2.5的监测性能仍待进一步考察;在PM2.5污染比较严重的高污染时段,TEOM1405、TEOM1405+除湿监测到的PM2.5日均质量浓度分别比手工监测结果偏低26%和11%,偏低较多。但这种高污染情况在珠三角地区出现的概率很低,故采用TEOM1405+除湿系统进行PM2.5长期自动监测是可取的。

In order to improve the PM2.5 monitoring accuracy,the tapered element oscillating microbalance has switched to using the novel aerosol condensation humidity controller in place of the traditional heating dehumidify methods.The comparison of PM2.5 monitoring results by traditional TEOM1405（using traditional heating dehumidify methods）,TEOM1405 with a condensation humidity controller（recorded as TEOM1405＋dryer）,and the traditional manual monitoring was performed at Guangdong atmospheric supersite.The results showed that the PM2.5 measured by TEOM1405 was about 13% lower than manual monitoring on the whole,while the average difference between TEOM1405＋dryer and manual monitoring was less than 5%.It can be concluded that the improvement of condensation humidity controller on PM2.5 monitoring was significant.The TEOM1405＋dryer system showed more stable and reliable performance than TEOM1405 in atmospheric environments of high humidity and low secondary particulate,the superiority was particularly striking during the rain;however its performance under high humidity and high secondary particulate conditions was unclear.During heavy pollution episode with high concentrations of PM2.5,the PM2.5 concentration monitored by TEOM1405,TEOM1405＋dryer was 26% and 11% lower than that of manual monitoring.However,the heavy pollution conditions were rarely happens in Pearl River Delta region,so TEOM1405＋dryer system was suitable for the long-term automatic monitoring of PM2.5.