室内空气中颗粒物对人体健康的影响

随着国民经济的快速发展和工业，城市化水平的不断提高，人们的工作，生活和居住条件得到了大幅度的改善，同时，由于建筑，室内装修，家具和现代家电与办公器材等造成的室内环境污染也引起了人们的高度重视。为此，本文介绍了国内外在室内空气颗粒物的来源，成分，浓度和粒径分布及其对人体健康影响等方面的研究进展，并提出了控制室内空气颗粒物污染的对策。     

吸入柴油机排出物对小鼠骨髓细胞微核出现率的影响

小鼠吸入过滤或未过滤的柴油机排出物，染毒８ｈ／ｄ，分别染毒２、５、８ｄ后，发现小鼠骨髓细胞微核率明显升高。吸入过滤后排出物的小鼠骨髓细胞微核出现率低于未过滤组。柴油机排出物对小鼠染色体有一定的损伤作用，过滤后的柴油机排出颗粒物中，致染色体损伤的物质减少，不同吸入时间（２、５、８ｄ）对小鼬骨髓细胞微核出现率，没有显著差异。     

重庆市主城区空气中颗粒物污染分析

颗粒物已成为环境空气污染最突出的问题之一。本文分析了重庆市主城区颗粒物污染的现状及其来源，并提出了解决颗粒物污染的对策建议。     

Air pollution and inhalation exposure to particulate matter of different sizes in rural households using improved stoves in central China

Household air pollution is considered to be among the top environmental risks in China.To examine the performance of improved stoves for reduction of indoor particulate matter(PM) emission and exposure in rural households, individual inhalation exposure to size-resolved PM was investigated using personal portable samplers carried by residents using wood gasifier stoves or improved coal stoves in a rural county in Central China.Concentrations of PM with different sizes in stationary indoor and outdoor air were also monitored at paired sites. The stationary concentrations of size-resolved PM in indoor air were greater than those in outdoor air, especially finer particles PM0.25. The daily averaged exposure concentrations of PM0.25, PM1.0, PM2.5 and total suspended particle for all the surveyed residents were 74.4 ± 41.1, 159.3 ± 74.3, 176.7 ± 78.1 and 217.9 ± 78.1 μg/m3,respectively. Even using the improved stoves, the individual exposure to indoor PM far exceeded the air quality guideline by WHO at 25 μg/m3. Submicron particles PM1.0 were the dominant PM fraction for personal exposure and indoor and outdoor air. Personal exposure exhibited a closer correlation with indoor PM concentrations than that for outdoor concentrations. Both inhalation exposure and indoor air PM concentrations in the rural households with gasifier firewood stoves were evidently lower than the reported results using traditional firewood stoves. However, local governments in the studied rural areas should exercise caution when widely and hastily promoting gasifier firewood stoves in place of improved coal stoves, due to the higher PM levels in indoor and outdoor air and personal inhaled exposure.     

广州市空气可吸入颗粒物污染现状研究

根据近年来广州市区空气质量监测资料,对广州市空气可吸入颗粒物（PM10）的污染水平、时空变化特征进行了分析、评价。结果表明,2007年广州市PM10平均浓度为0．077mg／m^3,符合国家空气质量二级标准。得益于空气污染控制取得的成效,近5年来PM10年均浓度呈下降趋势。受气候因素影响,PM10污染季节变化明显,冬季节较高,夏季节浓度较低;在空间分布上PM10污染呈现区域性发展趋势。     

山西太谷农村薪柴和蜂窝煤颗粒物和多环芳烃排放特征研究

测定并计算了太谷农村蜂窝煤和薪柴两种燃料颗粒物、CO、CH4和多环芳烃排放因子,其中多环芳烃包括16种美国环保局优控化合物、12种非优控母体多环芳烃、12种硝基多环芳烃和4种含氧多环芳烃.蜂窝煤4类多环芳烃化合物的排放因子分别为3.56±5.42、0.73±0.099、0.22±0.48和0.36±0.62 mg·kg-1,薪柴为62.6±41.3、20.4±3.61、4.44±6.18和0.84±1.00mg ·kg-1.薪柴大多数污染物排放因子高于蜂窝煤,但蜂窝煤多环芳烃排放因子的变异则高于薪柴.蜂窝煤和薪柴多环芳烃排放因子的成分谱有显著差异,除菲、荧蒽和苯并(b)荧蒽为共同优势排放物外,萘、芴、屈和苯并(k)荧蒽为蜂窝煤的特征排放物,芘、环戊烯(c,d)芘和苯并[a]蒽为薪柴的特征排放物.3-硝基荧蒽与3-硝基菲和2-硝基萘分别是蜂窝煤与薪柴排放的主要硝基多环芳烃.母体多环芳烃排放因子的气固比主要受分子量(挥发性)影响,衍生多环芳烃则与取代基的性质有关.蜂窝煤燃烧前期母体多环芳烃的排放因子显著高于后期,两个阶段的总排放因子分别为9.52±12.3和2.54±2.42 mg· kg-1,衍生多环芳烃在两个阶段的差别小于母体多环芳烃.     

Spatial variations in selected metal contents and particle size distribution in an urban and rural atmosphere of Islamabad, Pakistan

Spatial variations in total suspended particulate matter (TSP) were investigated for distribution of metals and particle size fractions in the urban and rural atmosphere of Islamabad, Pakistan. The metals Na, K, Fe, Mn, Pb, Cd, Cr, Zn, Ni and Co, and the particle fractions <2.5, 2.5-10, 10-100 and >100 microm were included in the study. TSP samples were trapped on glass fibre filters using high volume samplers and quantification of metals was done using Atomic Absorption Spectrometry employing HNO(3) based wet digestion. At the urban site, Na was dominant at 2.384 microg/m(3) followed by K, Fe and Zn with 0.778, 0.667 and 0.567 microg/m(3) as mean concentrations, respectively. The metal levels for the rural site ranged from 0.002 microg/m(3) for Cd to 1.077 microg/m(3) for Na. However, compared with the urban site, mean Pb concentration showed an almost two-fold enhancement, i.e., 0.163 Vs. 0.327 microg/m(3). Metals and particle size source identification was done using Principal Component Analysis and Cluster Analysis. Five sources were traced out for the urban site: industrial, soil, automobile emissions, metallurgical industries and excavation activities. For the rural site, four sources were recorded: agricultural, automotive emissions, excavation activities and metallurgical units. Collectively, for both the sites, PM(10-100) emerged as a major contributor to TSP, followed by PM(2.5-10), PM(<2.5) and PM(>100) in that order. The metals showed in general positive relationship with fine particulate fractions (PM(2.5-10), PM(<2.5)), and negative correlation with coarse fractions (PM(10-100), PM(>100)). Comparison with the corresponding data from various Asian sites revealed that the levels of Na, K, Fe, Mn, Co and Ni for the present study were lower than those reported for grossly polluted cities of the world.     

A method for quantifying bias in modeled concentrations and source impacts for secondary particulate matter

A method for quantifying source impacts for secondary PM_2.5 species is derived. The method provides estimates of bias in modeled concentrations. Adjusted concentrations match corresponding observations at monitored locations. Sources impacts on secondary species are estimated over the US for 20 sources. Community Multi-Scale Air Quality (CMAQ) estimates of sulfates, nitrates, ammonium, and organic carbon are highly influenced by uncertainties in modeled secondary formation processes, such as chemical mechanisms, volatilization, and condensation rates. These compounds constitute the majority of PM_2.5 mass, and reducing bias in estimated concentrations has benefits for policy measures and epidemiological studies. In this work, a method for adjusting source impacts on secondary species is developed that provides estimates of source contributions and reduces bias in modeled concentrations compared to observations. The bias correction adjusts concentrations and source impacts based on the difference between modeled concentrations and observations while taking into account uncertainties at the location of interest; and it is applied both spatially and temporally. We apply the method over the US for 2006. The mean bias for initial CMAQ concentrations compared to observations is −0.28 (OC), 0.11 (NO₃), 0.05 (NH₄), and −0.08 (SO₄). The normalized mean bias in modeled concentrations compared to observations was effectively zero for OC, NO₃, NH₄, and SO₄ after applying the secondary bias correction. 10-fold cross-validation was conducted to determine the performance of the spatial application of the bias correction. Cross-validation performance was favorable; correlation coefficients were greater than 0.69 for all species when comparing observations and concentrations based on kriged correction factors. The methods presented here address model uncertainties by improving simulated concentrations and source impacts of secondary particulate matter through data assimilation. Secondary-adjusted concentrations and source impacts from 20 emissions sources are generated for 2006 over continental US.     

Air quality improvement in Los Angeles—perspectives for developing cities

Air quality improvement in Los Angeles can inform air quality policies in developing cities. Emission control efforts, their results, costs and health benefits are briefly summarized. Today's developing cities face new challenges including regional pollution. Air quality issues in Beijing are briefly compared and contrasted with Los Angeles. Opportunities for co-benefits for climate and air quality improvement are identified. Air quality improvement in Los Angeles, California is reviewed with an emphasis on aspects that may inform air quality policy formulation in developing cities. In the mid-twentieth century the air quality in Los Angeles was degraded to an extent comparable to the worst found in developing cities today; ozone exceeded 600 ppb and annual average particulate matter <10 mm reached ~150 mg·m⁻³. Today's air quality is much better due to very effective emission controls; e.g., modern automobiles emit about 1% of the hydrocarbons and carbon monoxide emitted by vehicles of 50 years ago. An overview is given of the emission control efforts in Los Angeles and their impact on ambient concentrations of primary and secondary pollutants; the costs and health benefits of these controls are briefly summarized. Today's developing cities have new challenges that are discussed: the effects of regional pollution transport are much greater in countries with very high population densities; often very large current populations must be supplied with goods and services even while economic development and air quality concerns are addressed; and many of currently developing cities are located in or close to the tropics where photochemical processing of pollution is expected to be more rapid than at higher latitudes. The air quality issues of Beijing are briefly compared and contrasted with those of Los Angeles, and the opportunities for co-benefits for climate and air quality improvement are pointed out.     

Palm oil biodiesel: An assessment of PAH emissions, oxidative potential and ecotoxicity of particulate matter

This work assessed the impact of fuelling an automotive engine with palm biodiesel (pure, and two blends of 10% and 20% with diesel, B100, B10 and B20, respectively) operating under representative urban driving conditions on 17 priority polycyclic aromatic hydrocarbon (PAH) compounds, oxidative potential of ascorbic acid (OP^AA), and ecotoxicity through Daphnia pulex mortality test. PM diluted with filtered fresh air (WD) gathered in a minitunel, and particulate matter (PM) collected directly from the exhaust gas stream (W/oD) were used for comparison. Results showed that PM collecting method significantly impact PAH concentration. Although all PAH appeared in both, WD and W/oD, higher concentrations were obtained in the last case. Increasing biodiesel concentration in the fuel blend decreased all PAH compounds, and those with 3 and 5 aromatic rings were the most abundant. Palm biodiesel affected both OP^AA and ecotoxicity. While B10 and B20 exhibited the same rate of ascorbic acid (AA) depletion, B100 showed significant faster oxidation rate during the first four minutes and oxidized 10% more AA at the end of the test. B100 and B20 were significantly more ecotoxic than B10. The lethal concentration LC50 for B10 was 6.13 mg/L. It was concluded that palm biodiesel decreased PAH compounds, but increased the oxidative potential and ecotoxicity.