天津市环境空气恶臭污染状况与典型气态污染物识别

Odor Pollution Conditions and Typical Gaseous Pollutants in Urban Ambient Air in Tianjin City

以天津市中心城区和典型工业区为重点调查区域,通过网格法布设40个采样点,共采集不同季节的环境空气样品近1 300个.采用嗅觉测定法、分光光度法和GC-MS分别测定恶臭感官浓度、NH3和其他气态污染物的组成及浓度.结果表明：①天津市环境臭气浓度介于0-90之间,中心城区和工业区臭气浓度水平相当.夏季臭气浓度〈10的样品最多,占总样品量的42%,春季超过85%的样品臭气浓度〉20,秋季超过70%的样品臭气浓度〉20,说明春、秋两季环境恶臭污染较为严重.②NH3是检出率最高的恶臭物质.天津市夏、秋、春三季ρ（NH3）平均值分别为0.070、0.058和0.060 mg/m^3,各类功能区中居住区和混合区的ρ（NH3）较高.③秋季H2S的检出较为普遍,ρ（H2S）在0.006 4-0.220 0 mg/m^3之间,中心城区和工业区的ρ（H2S）平均值分别为0.014 0和0.023 0 mg/m^3,最高值出现在工业区.以物质浓度、嗅阈值和检出率为评估参数,通过分级赋值和多参数综合评分筛选出10种典型气态污染物,分别为NH3、CS2、苯、甲苯、间二甲苯、乙苯、1,2,4-三甲苯、乙醇、丙酮和异戊二烯;建立了臭气浓度与这10种污染物浓度的多元线性回归方程,该方程具有良好的统计学意义和相关性（P〈0.05,R=0.78）,表明这些气态化合物是影响城市空气恶臭感官污染的重要因素.

Odor pollution is one of the environmental issues that produces the most intense complaints from urban residents in China.Investigation into the odor pollution and gaseous pollutants in the urban ambient air of Tianjin City was carried out. Using the grid method,40 total monitoring sites covering various functional zones were uniformly allocated in the central urban area and a typical industrial area.In total,1300 air samples were collected using intensive field sampling methods in each season. The chemical composition and olfactory concentrations in the air samples were respectively analyzed by GC-MS and triangle odor bag method. Ammonia was separately determined by spectrophotometry. The results showed that： 1） Odor concentration values ranged from 0 to 90,and were equally matched between the urban and industrial areas. In summer,the highest percentage（ 42%） of odor concentrations were less than 10. The odor pollution was more serious in spring and autumn as compared with the other two seasons. In spring and autumn,the percentage of values with odor concentration over 20 was more than 85% and 70%,respectively. 2） Ammonia was the odorant with the highest detection rate. The average values of ρ（ NH3） in summer,autumn and spring were 0. 070,0. 058 and 0. 060 mg/m^3,respectively.The average value of ρ（ NH3） in the residential and the mixed areas were the highest among all types of functional zones. 3） The distribution of H2S varied with seasons,with the highest detectionrate in autumn. ρ（ H2S） was in the range of 0. 0064-0. 2200 mg/m^3,with the highest value in the industrial area. The average concentrations in the urban and industrial areas were 0. 0140 and 0. 0230 mg/m^3respectively. The typical gaseous pollutants were selected by comprehensive and quantitative evaluation of multiple parameters such as environmental concentration,olfactory threshold and detectable rate. Ten volatile substances were identified as ammonia,carbon bisulfide,benzene,toluene,1,3-dimethylbenzene,ethylbenzene,1,2,4-trimethylbenzene,alcohol,acetone and isoprene. A multiple linear regression equation between odor sensory concentrations and the selected ten substances was set up,and showed good statistical significance and correlation（ P〈0. 05,R = 0. 78）.This result indicates that these gaseous compounds were the most important substances influencing odor pollution in the urban ambient air.The survey results may provide reference for the establishment of an odor environmental standard.