表4-12x2分布分位数表(见GB4086.2-83) 250.00500.01000.02000.0250 D.05000,10000.1500 26.465082:.909203?.4811631,2456733.25621J3,9681336.4370939.4333841.5473 27.4677(29.3653330.9812532,7934534.8563535,5853 41,1830443.34471 288811630.313732 34.34952364638537,2115939,8012842. 6030.34048 3、四11.33.5344937.4848539.6994240.4817513.1879616,458948.75866 62131.747 0684239.0633341.3268042,125994,88q24.2257150.56999 6.78484386097840.6485642.9601643,7759546.59491 52.38431 2934240.1S82442.2402844.599 4313648,30538 51.20156 3.8093641713474J.8380346.2437347.091985{,02023 6.02160 037.4744 4}323243.2751845.44172478934448.7575651.7392855.3289457.8 7238.977440.5194842.862024t8431047.051049.5481450,4279153,4623357,1129559.66951 7440.375442.0096544.3981846.4169648.653512076252.1028355189258.8966.49 7614:.845443506245.405447.995350.285605:87168537821256.6198260.69663,32716 7843.31246450101147.48549,5815951.9104554.540145.4656258.6586462.48 804.79105465168190429051,1:19353.54008562128457.1531760.3914864.277846.9979 82146271040855.6246527673565 8896258846262.I322966,075?368.83026 16734 59.5703360.5368163,8762667.8760870,6687 49,2643851.08460537373555.9727058.4559361.25482622386365.6232869.678272.50912 8850,767305261730553123257,5823060.10301629429763.940936737323:.4838474.35137 90|52.275785.152456.8920759.1983061,754086.6346665.66269.1260373.2910976.19542 92537896535.69826684764560.8145763409166.329766.3555670.8815775.1004878.01 94538735.26196.06531624869565,0576768.0281?69.0676572.6397776.91959,896 96568328653.9861.6585164.063366294672970.3828214.400478.725428:7375 58.3618960.3561?63,2559165,6935763917271,4344772.5009476.1637980.540538358842 10563.7409465.8410668.878171:428231742520817:424027853640823537486 90.07746 l67.6310273,7893972.9218375.5500478.4503181.7228182.8670586.7915391.4710494,72292 1171.5370873,7612676.9870079.6915882.6824486.033987.2127991.2422096.0427099.37640 12075.46653775148102228815786.9232890.3641315726495.70464100623631043738 1251.4794817998.1762780897919789496959573160.17820105.2132187539 1308339000 89.29803922224655.4510298.0562010033126104.66223109.81102113.38000 13587.3154 89.85600 3.4364666,431 109.15612114.4t650118.0605 150946285102.1133510.9328109.1422512.6675816.60759 452122.69178128.2750513213749 51.5225106297910.010121140861021197:242802129042135.8400 16010.5972111.36033114.3498017.67926121.345612543998129.87005131.75606137.54569141.54749 16511.61814.504311165717112.9649112570016129.86088131.391136.29920142.18960145,25944 17015.78:918.6121220531126.26130130.0644134383?7135.7896140,84923146,83887150.97574 175119.9045122.83022127.05008130.56796134,4379413.7507140.26189145.40585151.49329155.69620 1801124032612.0107131.3055134.84451388206143.2096314.74126149.968771615263160.42064 18512817276131,20319135,57128 43.21131147.6717214922785154.53774150.81668165.14889 190132.3244:1356946139.84685 106 47,61043152.14105153.72135159.11251165,48525169,8080 95135.48711139.61916144、13188 2.01742155.61732158.22148163.69285170.158】7171.61623 200140.66045143.84279148.42601152.24099156.43197161.10028 72798168.27855174.83527179.35505 21014,03747152.31799157.04023160.96716528262170.08525171.759191746524184201401884232 22415745257160.82901165.68704169,7681741603517.414180.81324186671119.54919834170 230165.90321169.37343174.3642317851241183.063218812534189,8859195,8948820297752207.85237 093862206.2490420809780214.3957221.80 本表对于度v和下侧概率P给出x2分布的分位数x2P(v) 例:对于v=125和P=0.05,x2P()=100.1782 198·
续表 0.8500.90000.95006.97500.98000.9900 52|62.5:25665422169.832673.80986750214378.6576820035215832018 5665.953966q、9185174.4683285671679,8147183,513386,997690,401099 869.1192! 59847.777808D.9355982.2006585.9501889.4768792.8270697.03883t00.048 601.34110748970179.081983.276784.5795837191241.961715.3429.6012310269476 6273.5297776.6302181.3810285.6537386.9529490.‰15369.4i86597,8524210216625105.28946 6475.7154078.859648.67526880089.319293 96.8781l100.35868104.71633107.871 6728981281.085498.9649190.3489091.68179 99.3304312.81516107.25788110.45083 3079088.2501692.688549.069798 01.77592105.33024109.79130113.41834 7082.2555855270490.531235,0231896,3875410042518104,2149010.80822112.3169315.5758 2844301187.140552808279.353059.73101(2.8163 t0.27942114.83512118.1289 7486.6024389.95605 7688.7724292.16617 99.61683 9.97835101,07388 12.744)117.34616120.672 115.20255119.85035123,20912 78}90.9401694,3732 104.31594105,74182 113.91087117,65500122.3195125.73858 80s315756.57820101,87947196.62857108.0643412.3287s116.32106120.10168124.83922128.26131 8295269279878033104.1387410893729110.3627714.69489118.72613122.54280127.32440130.7756 8497.4307910,97999106.3948411.24226112.71225117.05654121.12629124.97857129.80869133.287 8650391031726647891543601507151.41912352170127.4911225916 810174812105372251108015841441.399127671259125412.8348213474548132973 9103.s040610.5650113.14527118.1358911.64846124.11632128.2894132.256313÷.20835140.78228 92106.05327109.,756315,38979120.4270812.65352126.46166130.681071346718013.6612143,26940 408.20791ts4471.6316512.1t1242557212.8325130590613.08346142128414:7517 9610.36169114.13071119.8709125,00007126.55381131.14122135,43305139.49076144,56697 12.51102116.3153012210773127.28207128.8492513.47567137.80315141.89384a47.1036 101.69821698012-3421129.5620131.14168135.80672140.1694914.2928349.4425 10512002194123.94688129.91796 6.s602514].62011146、06960156.27316135.5276815s.3146 110125.3764,129.38514135.48018 151.94848156.23042161.58074165.43532 15130.72295134.8348141.02970 48.24735 57.80759162.16614167,6101517153087 120|136.06196140.2325714656 63.64818168.8173173.61 3850159.57524164.69403169.4T142173.97843179.60397183.65286 30146.71930151.04520157.60992163.45314165.21920170.423131?5.27834179.85736185.57097289.6206 1351152.03844156.43973163.1610169.05604170.86085176.13831181.06986185,71951 140157.35169161,82699168.612 4.04783176.47088181.84034 91,56589197.45977201.68281 45162.6597167.20737174.t0098180.22912182.07991187.52992 97.39726203.36550207.6554l 50167.66177172.5812179.589063185,8045187.678019320769 55173.259151948185.05233191.3623019x.267161937423204.09794209.01805215.J486219.55159 6017s55418.3158190.51646196,91514198.84639204.5309209.838724.8088221.0189722807 46186193025390010171542.325802135 189,12348194.0174 99543209.97824215.81172221.24242226.35414232,71936237,29067 17519440301199.36300206.86680213.523632155316522.4383722936032321097528.50812431756 019.67857904703672123099121.04221002021612232.61980237.84632443704724904818 195095031108963217,38:8261258115692090989 190210.2838215.37106223.16025230.06439232145972326637243.95940249319815,97635260.775 195215.48295220684:25982355643237.69243.85953249.61596250292526176345269542 220.74413226,0210523.9942?241.05790243.1869224944512255,36415260.7354126754053272.42261 210 25864236.55493244.67064 254.20211260,59472265.5366522.12172279.06609284.04656 5,19336271,71723277,77920283.47140290.5557829,63234 230252.24677257.87882266,37810 75.16229282.814482889939294.798653020199307.18251 4026272553268.4707427.2376528.8024828711025293.8810300.18224306.03133i3.43659 250|273943927905043287 295.68863298.03882304.93956311.346163]7.36150324.83244330.18498 本表对于自由度v下侧梳率P给出x2分布的分位数xP(v 例:对于v=210和P=0.95,x2P()=244.80764
第二节气样采集管理 、气样的特性 通常所说的大气和废气实质上是空气的两个组成部分。地球表面被空气包围,由于 受自然和人为的两大因素所影晌,空气不可避免地要受到污染。距地球表面高度的不同 污染物的浓度不同。一般来说,近地面处污染物浓度较大。考虑到人们通常是活动在地 面上,从健康的角度出发,大气监测的样品也大多采集自距地面不过数来的空间 习惯上把环境空气中污染物的监测称为大气监测;把工厂企业炉窑由排气管道(烟 卤)排出的污染物的监测称为废气监测。 无论是大气还是废气都具有复杂性、变化性和无定形性等特性。 (一)空气的复杂性 空气中污染物的形态不像水质那样简单,一般以气态、蒸气和气溶胶等形态存在 气态是指某些污染物在常温常压下以气体形式分散在空气中,例:CO、SO2、NO2等。 蒸气是指某些物质在常温常压下为液体或固体,但由于它们的沸点或熔点较低,因 而能以蒸气态挥发到空气中,例:苯、汞、酚等。 气溶胶是由固体颗粒或液体颗粒悬浮于室气中的悬浮体,根据其不同性质和粒径常 见的有以下几种专门名词,以示分类 1.总悬浮微粒:空气中固体和液体颗粒的总称,其粒径为0.1~100微米,用大流量 和中流量采样器采样,收集在超细玻璃纤维滤膜上。 2.降尘:大气常规监测的一项指标,一般指粒径在30微米以上的颗粒物,用广口集 尘缸收集样品,一般每月一次 3.可吸入颗粒物:粒径在10微米以下的颗粒物,可由呼吸道吸入,对人体健康有害 用带有切割器的采样器样。 4.烟尘:这是工业企业炉窑管道中排出的固体颗粒物总称。通常用姻道气采样器用 等速采样的方法采集样品。 粉尘:多指作业现场无组织扩散排出的粒径在75微米以下的颗粒物,作为劳动保 护的一项指标可用粉尘采样器在车间空间采样 (二)空气的无定形性 空气是没有边界的,污染物一旦进入环境大气中,便会随风颗流,无影无踪,逐步 稀释,因此,随着测点位置与污染源间距离的加大,其浓度会越来越低,又由于风向的 不同和风力大小的不等,即使在以污染源为中心的等距同心圆上,各个方位测点污染物 浓度也会有极大的差异。此外,污染物在高度的分布上也是不均匀的,一般说来,随着 高度增加,污染物的浓度降低 总之,环境大气中污染物浓度的分布受到诸如风向、风力、气温、湿度和气压等因 素的影响,其浓度也有着瞬间不同的变化,这就意味着,即使在同一个测点上,也难于 采集到浓度完全相等的两份平行样品。 200·
二、空气和废气的采集管理 (…)采集系统构成 环境空气监测采样系统的组成:环境空气监测样系统由空气入口和进气导管 样品收集装置、采样器等组成。由于环境空气中污染物种类多,浓度范宽,存在状态 各异,监测目的又往往不同,必须选择相适应的监测采样系统 (1)空气入口和进气导管:对于气态污染物采样装置的入口不需要特殊设计,如仪 器在室内而采样入口暴露在室外颗粒物环境中,只需在入口处安装一个倒置的玻璃或聚 乙烯漏斗。采样入口至吸收瓶间的导管最长不超过5米。为防管内积水,导管不可打结, 弯曲半径不得小于5厘米。临时性采集气态污染物时,不必设空气入口和进气导管装置, 将采样器直接置于采样点即可。 采集总悬浮颗粒物等气溶胶污染物时,应配有合适的入口,如双坡顶盖入口、风罩 式入口或漏斗状具网罩入口等。 单位:mr 图47吸收管图 (a)气泡吸收管;(b)U型多孔玻板吸收管 2)气态污染物样品收集装置:气态污染物样品可用100毫升玻璃注射器、塑料袋 和球胆收集,常用的装置是气体吸收管(瓶)。气体吸收管(瓶)有多种,常用的是气泡 吸收管和多孔玻板吸收管(瓶)。气泡吸收管适用于采集气态污染物,抽气速度0.5~2 升/分钟。采样时,吸收管要垂直放置。多孔玻板吸收管(瓶)适用于采集气态或气态与 气溶胶共存的污染物。抽气速度0.1~1升/分钟。使用前应检查玻璃砂芯的质量。将多
孔玻板吸收管(瓶)内装5毫升(50毫升)水,以0.5升/分钟(2升/分钟)的流量抽 气,气泡分布应均匀,无特大气泡,气泡路径(泡沫高度)为50毫米±5毫米,阻力应 为47千帕士0.7千帕,见图4-7。 3)气溶胶污染物样品收集装置:气溶胶样品的采集常用冲击式吸收管和各种滤料 小型冲击式吸收管气泡出口内径为1毫米,气泡出口至管底距离为5毫米,内装5 10毫升吸收液,抽气速度必须保持28升/分钟。大型冲击式吸收管气泡出口内径为2.3 毫米,气泡出口至管底距离为5毫米,内装50~100毫升吸收液,抽气速度28升/分钟 详见图4-8 径 内径 径 出H 250 图8冲击式吸收管 (a)小型冲击式吸收管;(b)大型冲击式吸收管 常用的滤料有定量滤纸、玻璃纤维滤膜、过氯乙烯纤维滤膜、微孔滤膜和浸渍试剂 滤料等。 定量滤纸(中速和慢速)价格便宜、灰分低、纯度高、机械强度大,对一些金属尘 粒采样效果很好,且易于消化,空白值低,但抽气阻力大,有时孔隙不均匀,吸水性较 强 玻璃纤维滤膜机械强度差,但耐高温、阻力小、不易吸湿,可用于采集大气中总悬 浮颗粒物及可吸入颗粒物。样品还可以用酸或有机溶剂提取,用千分析不受滤膜组分及 所含杂质影响的元素。 过氯乙烯纤维滤膜不易吸湿、阻力小、带静电、采样效率高,能溶于乙酸乙酯,常 用于可吸入颗粒物采样和分散度的测定,也可用于分析可吸入颗粒物化学成分。 202