北京市石景山区室内空气中细颗粒物浓度水平及季节变化特征研究

Surveillance for fine particles concentration in air in Shijingshan district of Beijing

目的了解区域室内空气PM2.5浓度水平及分布特征。方法选择住宅、学校、办公场所共3个室内监测点和1个室外监测点(设在办公室外),采用重量法测定PM2.5与PM10的质量浓度。监测时间为2013年5月至2014年4月,每月连续监测7d,每天连续采样24-h。结果室内监测点PM2.5浓度总体均值和中位数分别为89μg/m3和61μg/m3;PM2.5浓度中位数Wilcoxon检验结果:住宅(69μg/m3)高于学校(58μg/m3)和办公室(50μg/m3),学校与办公室差异无统计学意义,办公室外(92μg/m3)高于室内;依据GB-3095-2012规定的浓度日均限值二级标准评价:χ2检验显示室外PM2.5浓度超标率(60.7%)高于室内(41.7%),室内PM2.5浓度超标率高于PM10(22.9%);4个监测点PM2.5日均浓度变化较大但变动趋势一致,共监测到9次PM2.5重度污染(>150μg/m3),累计室内17d(20.2%),室外24d(28.6%)。月均PM2.5浓度呈现2-3月(冬季)最高、7-8月(夏季)最低。Wilcoxon检验室内PM2.5/PM10中位数(84.7%)高于室外(64.1%)。t检验I/O均值显示PM2.5(67.2%)>PM10(53.9%)。室内与室外PM2.5浓度呈正相关,回归方程为y(μg/m3)=0.841x-14.804。结论监测地点室内空气污染较严重;室内空气PM2.5浓度与室外浓度密切相关,随着北京室外PM2.5浓度的季节性变化,室内浓度亦呈现冬季高夏季低的特点。

Objective To understand the concentration levels and distribution characteristics of fine particles（ PM2. 5）in air in Shijingshan district of Beijing. Methods Four surveillance sites were established,including 3 indoor sites and1 outdoor site. The 24 h air concentrations of PM2. 5and PM10 at the four sites were consecutively detected with gravimetric method for 7 days in every months from May 2013 to April 2014. Results Overall,the median of indoor PM2. 5concentration was 61 μg / m3,the PM2. 5concentration was higher in residence（ 69 μg / m3） than in school（ 58 μg /m3） and workplace（ 50 μg /m3）（ P 0. 05）. The difference between school and workplace had no statistical significance. The concentration of PM2. 5was lower in indoor site than in outdoor site（ 92 μg / m3）. According to national standard 3095- 2012,the proportion of indoor air PM2. 5concentration above 75 μg / m3 was significantly lower than that of outdoor site（ 41. 7% vs. 60. 7%,P 0. 05）. The indoor PM2. 5concentration was higher than indoor PM10concentration（ 22. 9%）. During the surveillance period,9 severe pollution events（ PM2. 5 150 μg / m3） were detected,which lasted for 17 days cumulatively at the indoor sites（ 20. 2%） and 24 days at the outdoor site（ 28. 6%）. The PM2. 5concentrations varied with season,which was highest in winter from January to March,and lowest in summer from July to August. The average ratio of indoor PM2. 5/ PM10 was 84. 7%,higher than that of the outdoor ratio（ 64. 1%）. The ratio of I / O of indoor PM2. 5was 67. 2%,higher than that of PM10（ 53. 9%）. The indoor air PM2. 5concentration was positively correlated with outdoor air PM2. 5concentration. Conclusion The indoor air PM2. 5pollution was serious in the surveillance area in Beijing. The indoor air PM2. 5concentration was closely correlated with outdoor air PM2. 5concentration and also varied with seasons.