Classification of residential exposure to nitrogen dioxide

In epidemiological studies of indoor nitrogen dioxide (NO₂) reported to date, only a limited number of measurements were made to estimate personal exposures. The accuracy of exposure estimates depends on the measurement error inherent in the samplers and in the sampling scheme. If categorical measures of exposure are used, the consequences of measurement error vary with classification rules. The effects of alternative measurement strategies on exposure classification were evaluated using NO₂ diffusion sampler measurements from 653 residences with gas cooking ranges. A time-series of consecutive 2-week integrated measurements was obtained for each home. During the winter season, the standard deviation was 26% of the mean. The probability of misclassification, a function of the mean and the standard deviation per home, was examined for three concentration classes (<25, 25–50, ⩾50 ppb). The average probability of misclassification was 10% for three 2-week integrated measurements across the winter and decreased to under 5% for continuous sampling (i.e. 13 consecutive 2-week samples). The sensitivity and predictive value were improved by increasing the number of samples obtained. The misclassification is determined by the number of concentration classes and by the relationship of class boundaries to the distribution of true means.     

Reproducibility of personal exposure estimates for nitrogen dioxide over a two year period

Continuous and categorical variables for estimation of exposure to NO₂ were measured twice over a 2-year period in a population of children of 6–12 years old. Children were selected who had not moved, and in whose houses no changes in gas appliances had been reported. The repeatability of the measurement of both the continuous and the categorical variables was excellent.     

A laboratory evaluation of a nitrogen dioxide personal sampling device

A series of chamber experiments was carried out to determine performance characteristics of nitrogen dioxide (NO₂) personal sampling devices (PSDs) under varying climatic conditions. The impact of extreme temperature on NO₂ PSDs was evaluated on two performance modes: (1) PSDs as stationary sampling devices; and (2) PSDs as exposure measuring devices. Extremely low temperatures affect both the accuracy and precision of the PSD measurements. Under conventional mobility patterns, the extreme temperature impact does not affect the ability of PSDs to measure personal exposures to NO₂ accurately. NO₂ PSD is a simple, robust, lightweight, unobtrusive, and easy-to-use sampler that measures exposure to NO₂ with sensitivity and time resolution not previously available with other diffusion monitors.     

黄石市大气二氧化氮健康效应与人群暴露风险

为揭示黄石市二氧化氮(NO₂)的健康效应和人群暴露风险特征,收集2015～2020年黄石市NO₂浓度、非意外死亡、呼吸系统和循环系统疾病每日死亡人数、内科疾病每日住院人数以及气象要素等资料,探究了黄石市NO₂时空变化,采用时间序列的半参数广义相加模型(GAM)定量评价NO₂对黄石市死亡病例和内科住院病例人数的影响,并对居民的暴露风险(R*)进行评估.结果表明:黄石市NO₂的浓度年内变化呈“U”型,春冬污染较严重,人群密集和工业区NO₂浓度稍高.在最佳滞后时间下,NO₂浓度每增加10μg/m³,非意外死亡、呼吸系统和循环系统病例的死亡人数在lag01、lag3、lag1时达到最大,增加百分比(ER)值分别为1.93%(95%CI:-2.10,6.14),2.13%(95%CI:-6.56,11.62),4.82%(95%CI:-0.22,10.02),内科疾病每日住院人数在lag05时达到最大,增加百分比(IP)值...     

Spatial variance and assessment of nitrogen dioxide pollution in major cities of Pakistan along N5-Highway

This paper discusses the findings of the first car MAX-DOAS (multi-axis differential optical absorption spectroscopy) field campaign (300 km long) along the National Highway-05 (N5-Highway) of Pakistan conducted on 13 and 14 November, 2012. The main objective of the field campaign was to assess the spatial distribution of tropospheric nitrogen dioxide (NO₂) columns and corresponding concentrations along the N5-Highway from Islamabad to Lahore. Source identification of NO₂ revealed that the concentrations were higher within major cities along the highway. The highest NO₂ vertical column densities (NO₂ VCDs) were found around two major cities of Rawalpindi and Lahore. This study also presents a comparison of NO₂ VCDs measured by the ozone monitoring instrument (OMI) and car MAX-DOAS observations. The comparison revealed similar spatial distribution of the NO₂ columns with both car MAX-DOAS and satellite observations, but the car MAX-DOAS observations show much more spatial details. Maximum NO₂ VCD retrieved from car MAX-DOAS observations was up to an order of magnitude larger than the OMI observations in urban areas.     

广州市多污染物联合暴露的健康效应评估

本研究应用贝叶斯核机器回归(BKMR)分析了广州市2015~2018年大气主要污染物(SO₂、NO₂、PM₁₀、PM_2.5、CO和O₃)与非意外死亡之间的联合健康效应。结果表明,6种污染物对健康结局均存在较大影响。随着其它污染物固定百分位数浓度的增加,SO₂、O₃或NO₂的浓度从第25百分位数变化到第75百分位数导致的效应值的绝对值逐渐升高;相反,PM_2.5、CO或PM₁₀的浓度从第25百分位数变化到第75百分位数导致的效应值的绝对值逐渐减少。在累积滞后0~1d时,多种空气污染物的混合暴露对非意外死亡人数的影响效应值为正,与最低浓度相较,当所有污染物的浓度增至第90百分位数时,人数非意外死亡人数将增加21.98%(95%CI:3.04%,44.41%)。通过应用BKMR模型,本研究证实多种污染物的暴露可对广州市人群公共健康造成联合的综合影响。在污染物的防控治理上,不仅需要针对当地主要空气污染物,还需加强对多污染物暴露的防控。     

Heterogeneous uptake of nitrogen dioxide on Chinese mineral dust

Mineral dust is one of the major aerosols in the atmosphere. To assess its impact on trace atmospheric gases, in this work we present a laboratory study of the effect of temperature on the heterogeneous reaction of NO₂ on the surface of ambient Chinese dust over the temperature range from 258 to 313 K. The results suggest that nitrogen dioxide could mainly be adsorbed on these types of Chinese mineral dust reversibly with little temperature dependence. Similar to a previous study on NO₂ uptake on mineral aerosols, the uptake coefficients are mainly on the order of 10^− 6 for the Chinese dust, when BET areas are taken into account. HONO was observed as a product, and its formation and decomposition on Chinese mineral dust during the uptake processes were also studied. The complete dataset from this study was compiled with previous literature determinations. Atmospheric implications of the heterogeneous reaction between NO₂ and mineral dust are also discussed, in an effort to understand this important heterogeneous process.     

Ozone,sulfur dioxide,and nitrogen dioxide trends at rural sites located in the united states

We have investigated the existence of trends for ozone, sulfur dioxide, and nitrogen dioxide at rural sites in the U.S. For the ozone analysis, at 54 of the 77 sites (70%) for the 10-year analysis (1979–1988) and at 118 of 147 sites (80%), with at least 4 years of data for the 5-year analysis (1984–1988), there was no indication of trends, either positive or negative. For the 10-year analysis, ozone sites in the Southern and Midwest forestry regions showed more positive than negative signiicant slope estimates. For the 5-year analysis, similar results were obtained, except that the mid-Atlantic region also experienced more positive than negative significant slope estimates. In most of the agricultural regions, there were not many significant trends in either the 10- or 5-year analysis. However, for the agricultural Appalachian region, 50% and 34% of the trends, respectively, were significant and there were more positive than negative significant ozone trends for both the 10- and 5-year periods. For sulfur dioxide, there was an indication of trends at 37 of 64 sites (58%) for the 10-year analysis (1978–1987). For the 5-year analysis (1983–1987), with at least 4 years of data, there was no indication of trends at 115 of 137 sites (84%). For sites in some regions of the U.S., there is an indication that sulfur dioxide concentrations have declined for both the 5- and 10-year periods, but the rate of decline on an aggregate basis has slowed in the 5-year period. There is a strong indication that the sulfur dioxide level decreased at many sites in the Midwest forestry and the Corn belt agricultural regions for the 10-year period. In the Southern forestry and Appalachian agricultural regions, many sites showed a decrease in the index for the 10-year, but not the 5-year, period. The lack of monitoring data for nitrogen dioxide made any conclusion extremely tenuous.     

Integrated assessment of promising measures to decrease nitrogen losses from agriculture in EU-27

Following the recognition of the detrimental effects of nitrogen (N) losses from agriculture in the European Union (EU) on human health and environment, series of environmental policy measures have been implemented from the early 1990s onwards. However, these measures have only been partially successful. Clearly, there is lack of integration of available measures and there is lack of enforcement and hierarchy; which measures should be implemented first? We identified and assessed three ‘most promising measures’ to decrease N losses from agriculture, i.e., (i) balanced fertilization, (ii) low-protein animal feeding, and (iii) ammonia (NH₃) emissions abatement measures. Environmental-economic assessments were made using scenario analyses and the modeling tools MITERRA-EUROPE and CAPRI.In the baseline scenario (business as usual), N use efficiency (NUE) in crop production increases from 44% in 2000 to 48% in 2020, while total N losses decrease by 10%. Implementation of promising measures increases NUE further to 51–55%, and decreases NH₃ emissions (by up to 23%), nitrous oxide (N₂O) emissions (by up to 10%) and N leaching losses (by up to 35%). Differences in responsiveness to promising measures varied between and within Member States. Strict implementation of balanced fertilization in nitrate vulnerable zones, as defined in the Nitrates Directive, decreases total farmers’ income in EU-27 by 1.7 billion euros per year. Implementation of all three measures decreases farmers income by 10.8 and total welfare by 17 billion euros per year, without valuing the environmental benefits.The study presented here is one of the first EU-wide integrated assessments of the effects of policy measures on all major N losses from agriculture and their economic costs. Our results show that the most promising measures are effective in enhancing NUE and decreasing NH₃ and N₂O emissions to the atmosphere and N leaching to groundwater and surface waters, but that income effects are significant. The order of implementation of the measures is important; NH₃ emissions abatement measures must be implemented together with balanced N fertilization.     

An efficient absorbing system for spectrophotometric determination of nitrogen dioxide

A simple and sensitive spectrophotometric method for determination of atmospheric nitrogen dioxide using o-nitroaniline as an efficient absorbing, as well as diazotizing, reagent is described. o-Nitroaniline present in the absorbing medium is diazotized by the absorbed nitrite ion to form diazonium compound. This is later coupled with 1-amino-2-naphthalene sulphonic acid (ANSA) in acidic medium to give red-violet-coloured dye,having λ_max = 545 nm. The isoamyl extract of the red azo dye has λ_max = 530 nm. The proposed reagents has ≈ 100% collection efficiency and the stoichiometric ratio of NO₂:NO₂⁻ is 0.74. The other important analytical parameters have been investigated. By employing solvent extraction the sensitivity of the reaction was increased and up to 0.03 mg m⁻³ nitrogen dioxide could be estimated.     

中国部分地区铅暴露儿童健康风险评价

通过解析我国现有血铅浓度数据,采用无阈值剂量效应曲线,计算了我国部分地区轻度智力发育迟缓(MMR)的发生概率.最后利用MMR发生率以及生命周期表,计算了相应的伤残调整寿命年.结果表明:我国儿童血铅浓度几何均值和几何标准差分别为5.94,1.58μg/dL,超标率为12.74%,而由于铅暴露污染所导致的儿童MMR发生率和伤残调整寿命年(DALYs)分别为0.78%和0.10a.计算结果表明,我国儿童的铅暴露风险低于非洲,南美以及部分中东地区,远高于北美以及欧洲,与除日本以外的其他亚洲国家基本持平.     

Health risk assessment of dietary exposure to polycyclic aromatic hydrocarbons in Taiyuan, China

Sixteen polycyclic aromatic hydrocarbons （PAHs） were determined in 24 duplicate-diet samples from people in Taiyuan during summer and winter in 2009. Dietary intake of PAHs for 2862 participants was subsequently estimated by a survey in Taiyuan. Results from these 24 samples were compared with a raw food study in Taiyuan in 2008. Three main sources of dietary PAHs are vegetables, wheat flour and fruits, the sum of which contributes 75.95% of PAHs in dietary food. Compared to the estimated value in raw food, much more B[a]Peq （benzo[a]pyrene equivalents） were detected in food samples collected in the duplicate-diet study in Taiyuan （60.75 ng/day）. The cooking process may introduce more B[a]Peq into food, and the relative contribution of 16 PAHs in the diet would be changed during the cooking procedure.     

Long-term performance of a field-release system for the intermittent exposure of agricultural crops to sulphur dioxide

A computer-controlled field-release system has been used to expose winter barley to sulphur dioxide in different combinations of concentration and duration. Three plots were exposed to nominal concentrations above background of 204 ppb × 1 day, 68 ppb × 3 days and 34 ppb × 6 days, within a repeated 6-day cycle (1 ppb = 1 nlℓ⁻¹). Similar total doses were adminstered, and the target 6:2:1 ratio of concentrations was achieved. The overall performance of the system with regard to concentrations and durations, wind direction and reliability is discussed.     

Spatial and temporal patterns in nitrogen dioxide concentrations in a hot desert region

This paper reports seasonal and spatial variations in the ambient air concentration of nitrogen dioxide throughout the State of Bahrain, from February to December 1992. Monitoring sites were chosen to include urban areas with high traffic density, suburban areas with low traffic density, commercial and industrial areas. Correlations between meteorological parameters and mean NO₂ concentrations were analysed, and NO₂ levels were only significantly correlated with temperature (r = 0.63). Only February, a winter month, showed a significantly lower concentration of NO₂ with an overall mean value of 23 μgm⁻³, whereas in August, a summer month, it was 33 μgm⁻³. The results revealed that in a hot region like Bahrain, NO₂ concentrations do not show significant monthly variations. Also summer-averaged NO₂ values exceeded corresponding spring and winter values. In cold regions opposite patterns were observed. Moreover, the results revealed significant spatial variations in NO₂ concentrations. In suburban areas with low traffic density, the overall mean NO₂ level was 15, with a range of 12–17 μg m⁻³, while in urban areas with high traffic density, the overall mean value was 52 with a range of 44–60 μg m⁻³. The mean NO₂ value in industrial sites with low traffic density was 21 with a range of 14–27 μg m⁻³, whereas in the same areas near major roads, it was 32 with a range of 31–32 μg m⁻³. These results indicate that automobiles exhaust are the dominant source of NO₂ in Bahrain. The highest NO₂ levels were found in roads with high traffic density, which are narrow, with several traffic lights and roundabouts, suggesting the effect of road geometry on NO₂ levels.     

Cancer risk assessment from exposure to trihalomethanes in tap water and swimming pool water

We investigated the concentration of trihalomethanes （THMs） in tap water and swimming pool water in the area of the Nakhon Path- om Municipality during the period April 2005-March 2006. The concentrations of total THMs, chloroform, bromodichloromethane, dibromochloromethane and bromoform in tap water were 12.70-41.74, 6.72-29.19, 1.12-11.75, 0.63-3.55 and 0.08-3.40 μg/L, respectively, whereas those in swimming pool water were 26.15-65.09, 9.50-36.97, 8.90-18.01, 5.19-22.78 and ND-6.56 μg/L, respectively. It implied that the concentration of THMs in swimming pool water was higher than those in tap water, particularly, brominated-THMs. Both tap water and swimming pool water contained concentrations of total THMs below the standards of the World Health Organization （WHO）, European Union （EU） and the United States Environmental Protection Agency （USEPA） phase Ⅰ, but 1 out of 60 tap water samples and 60 out of 72 swimming pool water samples contained those over the Standard of the USEPA phase Ⅱ. From the two cases of cancer risk assessment including Case Ⅰ Non-Swimmer and Case Ⅱ Swimmer, assessment of cancer risk of nonswimmers from exposure to THMs at the highest and the average concentrations was 4.43×10^-5 and 2.19×10^-5, respectively, which can be classified as acceptable risk according to the Standard of USEPA. Assessment of cancer risk of swimmers from exposure to THMs at the highest and the average concentrations was 1.47×10^-3 and 7.99×10^-4, respectively, which can be classified as unacceptable risk and needs to be improved. Risk of THMs exposure from swimming was 93.9%-94.2% of the total risk. Cancer risk of THMs concluded from various routes in descending order was： skin exposure while swimming, gastro-intestinal exposure from tap water intake, and skin exposure to tap water and gastro-intestinal exposure while swimming. Cancer risk from skin exposure while swimming was 94.18% of the total cancer risk.     

松嫩平原地下水氮污染健康风险评估

为探明松嫩平原地下水氮污染现状及其对人类健康的影响,利用浅层地下水采样测试数据,运用地统计学分析及三角随机模型开展了儿童和成人群体摄入氮污染风险评估及其不确定性研究.结果表明：研究区氮污染物主要存在形式为硝态氮,样品超标率为44.35%,最大值达到566.2mg/L,硝态氮浓度大于20mg/L的区域约占区内总面积的60%,主要分布在东中部高平原地区,西部山前倾斜平原污染较轻;以Isight5.9-2为平台,基于三角模糊法耦合随机模型,考虑人类活动及农业发展的影响,将研究区划分为不同单元,非致癌风险排序为：评价单元Ⅲ>评价单元Ⅱ>评价单元Ⅰ,且单元Ⅲ污染物主要来源于农业活动,单元Ⅲ、Ⅱ区域风险远高于安全阈值1,会对儿童和成人群体健康造成潜在危害,对儿童威胁更大;污染物浓度和参数的不确定性对风险值影响的波动范围较大,三角随机模型对数据变化更为敏感,可降低三角模糊法的不确定性,单元Ⅰ儿童风险区间值横跨安全阈值1,可能会误导污染防控决策;硝态氮浓度对风险贡献率均在90%以上,明确对硝态氮浓度参数随机抽样的必要性,提高评价结果的可靠性.     

用尿中1-羟基芘评价人体暴露PAHs的肺癌风险

 采集并分析了100名不吸烟成人24h呼吸的空气样品和尿液样品,建立了人尿中1-羟基芘(1-OH-Py)浓度与苯并(a)芘(BaP)、芘(Py)等14种多环芳烃(PAHs)呼吸暴露浓度的定量关系.参考现有关于BaP空气污染浓度与肺癌死亡率的剂量-反应关系模型,推导出用尿中1-OH-Py预测人体呼吸暴露PAHs的肺癌风险模型.用建立的模型对100名受试者进行了肺癌风险评价,结果表明,一般人群BaP暴露的肺癌风险约为11/10万,焦炉工人约为160/10万;若同时考虑14种PAHs的BaP当量毒性,则其相应肺癌风险要高出约0.5倍.一般人群的尿中1-OH-Py的生物暴露限值为0.11μmol/mol肌酐,焦炉工人为1.90μmol/mol肌酐.     

中国儿童铅暴露健康风险评估

通过检索中国生物医学文献数据库和中国全文期刊数据库,以及相关文献追溯等途径检索收集,并按照拟定的标准筛选国内1994-2012年公开发表的有关儿童血铅水平的论文;根据调查对象居住地点,将论文分为以城市儿童为研究对象和以农村儿童为研究对象两类.在此基础上,按照WHO推荐的评价方法,评估儿童铅暴露引起的轻度精神发育迟滞(以精神发育迟滞MMR发病率表征)及其疾病负担(以伤残调整寿命年DALYs表征),以此评价中国儿童铅暴露的健康风险.结果表明,中国城市儿童的血铅均值为7.02 μg·dL-1,MMR的发病率为17.9‰,农村儿童相应值分别为7.88 μg·dL-1和19.8‰.城市和农村儿童因铅暴露导致的DALYs损失分别为每千人39.4例和43.2例.结果提示,我国儿童铅暴露所致MMR发病率高于西太平洋区的平均水平,应采取积极的措施降低儿童铅暴露水平.     

环境流行病学研究中全血长期保存与RNA提取方法

RNA是在基因表达层面探究分子生物学机制的重要研究对象.由于RNA化学性质活泼、结构不稳定,并且内外源RNA酶无处不在,如何从环境流行病学研究收集到的全血样本中提取出高质量的总RNA是困扰研究人员的一大难题.本研究旨在建立一种能长期保存全血样本并从中提取出高质量总RNA的方法.通过将环境流行病学研究中采集到的少量新鲜全血立即与10倍体积的TRIzol试剂混匀后置于-80℃冰箱中,可保护RNA在长期保存过程中不发生降解.针对长期保存的全血-TRIzol混合体系,在经典的TRIzol一步法基础上,无需将全血样本分装至不含RNA酶的1.5 mL离心管,直接在较大操作空间(不含RNA酶的15 mL离心管)中进行总RNA相分离、沉淀、洗涤等操作,并在总RNA晾干前再增加离心并吸取少量残留液体操作,缩短自然晾干时间.本方法无需离心、分离血浆、裂解红细胞等繁杂的前处理步骤,极大地简化了操作步骤,减少了采样工作量,实现了对全血样本的低成本长期保存.通过增大操作空间、改进晾干操作,本方法显著提高了总RNA样本的完整性和纯度.使用本方法提取出保存一年的全血总RNA产率为(9.18±2.10)μg·mL~(-1),完整性指标RIN值和28S/18S分别为8.98±0.18和1.08±0.08,纯度指标OD_(260)/OD_(280)和OD_(260)/OD_(230)分别为2.18±0.04和1.70±0.00.保存两年的全血提取出总RNA的产率、完整性及纯度仍然可以满足下游实验要求.