Monday, March 31, 2008

證明 ζi (ppb) * ρa (kg / m^3) * (Mi / Ma) = mi (μg / m+3)

1.證明 ζi (ppb) * ρa (kg / m^3) * (Mi / Ma) = mi (μg / m^3)

ζi(ppb):污染物i混合比以ppb表示
ρa(kg/m^3):空氣密度,以kg/m^3表示,20℃,1 atm時,ρa0 = 1.2 kg/m^3
ρa(kg/m^3):空氣密度,任何溫度T(K),壓力(atm)下,ρa = ρa0 * (293/T) * (P/1)
ρa(kg/m^3):空氣密度,25℃,1 atm時,ρa = 1.18 kg/m^3
Mi:污染物i的分子量,g/mole
Ma:空氣分子量,28.97 g/mole
mi:污染物i的質量濃度,μg/m^3
Ci :污染物i莫耳濃度,the molar concentration

解答:
課本公式(A) ζi = Ci / Ctotal
課本公式(B) Ctotal = N / V = P / RT
課本公式(C) ζi = Ci / (P / RT) = (Pi / RT) / (P/RT) = Pi / P

1. P = Ctotal * RT =Ca * RT

2. P = ﹝Ca (mole/m^+3) * Ma (g/mole) ﹞ * ﹝ RT / Ma (g/mole) ﹞
= ρa (g/m^3) * RT / Ma (g/mole) = ρa (kg/m^3 * 10^-3) * RT / Ma (g/mole)

3. Pi = ﹝mi(g/m^3) * RT ﹞ / Mi(g/mole)
= ﹝ mi(μg/m^3) * 10^6 ﹞ * RT / Mi (g/mole)

4. ζi (ppb) = Pi / P * 10^9

4. ζi (ppb) =
﹝mi(μg/m^3) * 10^6 * RT / Mi (g/mole) ﹞ / ﹝ρa (kg/m^3*10^-3) * RT / Ma (g/mole) ﹞

4. ζi (ppb) = ﹝ mi(μg/m^3) / Mi (g/mole) ﹞ / ﹝Ma (g/mole) /ρa (kg/m^3) ﹞ * 10^9

5. ζi (ppb) *ρa (kg/m^3) * ﹝Mi (g/mole) / Ma (g/mole) ﹞ = mi(μg/m&3)

Sunday, March 30, 2008

▉黑體輻射的總能量和絕對溫度的四次方成正比(輻射能量越大,最大能量輻射波長越短)

▉黑體輻射的總能量和絕對溫度的四次方成正比(輻射能量越大,最大能量輻射波長越短)

★所有的物體都有輻射,都會釋出能量或吸收能量;一般現象為「熱(heat)」,熱平衡狀況下,物體在所有波長的輻射能量(熱輻射_Thermal radiation)會呈現連續的光譜。

★1859年,德國物理學家 Kirchhoff (克希何夫)提出輻射定律(law of radiation),在確定的溫度下,物體對輻射能量之放射率或吸收率與表面之性質有關。

★1879年由J. Stefan(史蒂芬)提出黑體輻射的總能量(F,溫度越高,輻射能量越大)和絕對溫度(T)的四次方成正比,F = sT4,溫度接近6000K黑體之總輻射量,乃為史蒂芬波茲曼定律(Stefan-Boltzmann law),其中,史蒂芬波茲曼常數(Stefan-Boltzmann constant)→s (sigma) = 5.671 x 10-8 W.m-2.K-4 (Watt.m-2.K-4,為實驗決定的常數)。

★1893年Wien(韋恩)計算出輻射能波長之變化,物體最大能量之輻射波長(L)與物體絕對溫度(T)成反比,韋恩位移定律(Wien displacement law),TLmax=常數,此關係稱之韋恩位移定律,L max = 2897*106/T(太陽輻射最大之波長大約在0.475 mm 相當於藍色光,利用韋恩位移定律可知太陽的「色溫」約為6000K)。
◎Wien(韋恩)定理:溫度越高,最大能量輻射波長越短。
(1)熱物體看起來呈藍色。冷物體看起來呈紅色。
(2)恆星的表面_像似黑體。藍色恆星的表面溫度會高於紅色恆星的表面溫度。

★以上結論:
(1)溫度越高,輻射能量越大。
(2)溫度越高,最大能量輻射波長越短。
結果a:輻射能量越大,最大能量輻射波長越短。
結果b:溫度較高者,以短波長輻射居多,溫度較低者,絕大部分是長波輻射。

Friday, March 28, 2008

森林釋出異戊二烯(isoprene)對大氣品質之影響

  • 異戊二烯的分子式為C5H8,化學式為CH2=C(CH3)CH=CH3,常溫下為無色揮發性液體,活性高。
  • 全球的植物一年所釋出之異戊二烯約有3×1011公斤,這和植物釋出甲烷的量相近,和甲烷不同的是異戊二烯的活性大,會迅速的和羥自由基產生氧化反應,又會和氮氧化物發生複雜的反應產生臭氧,所以其在大氣化學中扮演著重要的角色
  • 溫度與光度為影響異戊二烯釋出量的兩個最重要的因素之一,異戊二烯的釋出對於溫度非常的敏感,葉面溫度升高10℃後,短時間內異戊二烯的釋出量也會增加為原來的數倍,增加的量會隨著樹種而有所不同,有些樹種可能增加至原來的十倍。另一個重要因素為光度,異戊二烯釋出量會隨著光度增加而增加。根據研究結果顯示,植物的光合作用速率對於溫度的變化有靈敏的反應,當溫度上升達約44℃之後,光合作用的速率會迅速的下降,這個時候葉片已經遭到重大且不可還原的破壞,植物在高溫的情況下會釋出較多量的異戊二烯,來幫助植物抵抗高溫,使它在一定的範圍內保護光合作用免於受高溫的危害。當葉片暴露在光照強度1000μmolm-2s-1(此約為陽光強度的一半)和純氮的環境(可抑制植物釋出異戊二烯)中,在葉片沒有釋出異戊二烯的情況下,當溫度達到37.5℃時,葉綠素的螢光放射量會增加(此現象代表葉片已經遭到重大的破壞),而在有加入17.5ppm異戊二烯之情況下,葉綠素的螢光放射量在45℃時才增加。
  • 有些樹種會釋出多量的異戊二烯,與大氣中之氮氧化物反應產生臭氧,來污染空氣。因此在含有高濃度氮氧化物之環境,如工業區及都市,其周遭之公園及行道樹之樹種選擇極為重要,除考慮其生長所需條件及遮蔽效果外,更應選擇無或低異戊二烯釋出量之樹種,以減少臭氧之產生,期能降低臭氧對人體及動植物的危害。

    資料來源: 吳金村, 森林釋出異戊二烯對大氣品質之影響, 中興大學森林學系.

Wednesday, March 26, 2008

南極冰棚裂解 暖化加劇警訊

美國科羅拉多大學國家雪冰資料中心(NSIDC)拍攝到的衛星影像顯示,在全球暖化效應影響下,幅員遼闊的南極威爾金冰棚已開始解體。位於冰棚一角、面積廣達四百一十四平方公里的一塊巨冰,近日突然崩裂。科學家指出,這是因為一座長四十一公里、寬二.四公里的冰山,先在二月二十八日從冰棚西南前緣處斷裂所致。
二○○二年以來最大規模崩裂
威爾金冰棚是一塊遼闊的常年浮冰,面積達一萬二千九百五十平方公里,位於南極半島西南部,距離南美洲約一千六百零九公里。由於近來不斷出現冰塊裂解的情形,包括二○○二年、一九九五年都有更大規模的冰裂,因此該冰棚剩餘部份目前僅由位於兩座島嶼中間的一條薄冰柱支撐。
科學家由於在冰棚分裂的數小時內就注意到相關的衛星影像,因此馬上通令衛星攝影機轉向,甚至搭機盤旋在冰棚裂解處上空,拍攝難得的照片與畫面。據參與拍攝的科學家指出,現場如小屋般大小的巨型冰塊四散,猶如炸彈爆炸的場景。
NSIDC首席科學家史卡波斯在聲明中說:「如果(冰棚)繼續向後退,這個最後的支撐物也要解體,我們可能在未來數年喪失掉整個冰棚的一半。」他指出,冰棚裂縫處蓄積了滿滿的水,並且斷裂、瓦解。參與調查的英國南極調查所科學家沃芬表示,這種崩解方式,很像是用錘子重擊強化玻璃後的情形。
科學家憂此次是大崩裂關鍵
科學家擔心,威爾金冰棚剩餘部份將來也可能裂解。沃芬預測威爾金冰棚將在十五年後崩裂,但明年以前應該還能保持完整,因為南極的夏季已結束,即將步入寒冷季節。雖然最近斷裂的部份僅佔整體冰棚的四%,卻是能引起進一步分崩離析的關鍵部份。
科學家不擔心這起冰棚崩裂事件會導致海平面升高,但認為這是全球暖化惡化的跡象,意味著氣候系統的翻轉點。南極半島西部過去半世紀來出現了地球上最劇幅的增溫現象,平均每十年增溫攝氏○.五度。

Tuesday, March 18, 2008

About CARMA

At its core, Carbon Monitoring for Action (CARMA) is a massive database containing information on the carbon emissions of over 50,000 power plants and 4,000 power companies worldwide. Power generation accounts for 40% of all carbon emissions in the United States and about one-quarter of global emissions. CARMA is the first global inventory of a major, emissions-producing sector of the economy.
CARMA is produced and financed by the Confronting Climate Change Initiative at the Center for Global Development, an independent and non-partisan think tank located in Washington, DC.
The objective of CARMA.org is to equip individuals with the information they need to forge a cleaner, low-carbon future. By providing complete information for both clean and dirty power producers, CARMA hopes to influence the opinions and decisions of consumers, investors, shareholders, managers, workers, activists, and policymakers. CARMA builds on experience with public information disclosure techniques that have proven successful in reducing traditional pollutants.
For several thousand power plants within the U.S., CARMA relies upon data reported to the Environmental Protection Agency by the plant operators themselves as required by the Clean Air Act. CARMA also includes many official emissions reports for plants in Canada, the European Union, and India. For non-reporting plants, CARMA estimates emissions using a statistical model that has been fitted to data for thousands of reporting plants in the U.S., Canada, the EU, and India. The model utilizes detailed data on plant-level engineering and fuel specifications. CARMA reports emissions for the year 2000, the current year, and the future (based on published plans).
CARMA also aggregates data on individual plants to the level of operating companies, parent corporations, and several geographic entities (continents, countries, states/provinces, and cities worldwide, with additional reports for U.S. metro areas, congressional districts, and counties). The database is updated quarterly to reflect changes in ownership, construction, renovation, planned expansions, and plant retirements. CARMA is meant to be a repository of the best available information on power sector carbon emissions. Our policy is to correct any errors or omissions if suggested revisions are verified by an independent third party.

cite from http://carma.org/blog/about

Sunday, March 16, 2008

期末報告的題目, 摘要, 參考文獻期限為4月20日, 2008年

due date for the title, abstract, reference of 2008 term project

期末報告的題目, 摘要(20 - 40 lines), 參考文獻 (3 to 5 references)期限為4月20日, 2008年
April 20, 2008-----
due date for the title, abstract (20 - 40 lines), references (3 to 5 references) of the 2008 project


期末報告於6月19日, 2008年交
,June 19, 2008-----
due date for the term project

空污的期末報告題目

可參考以下網站或資料

1. 台灣環保署歷年研究計畫查詢

http://sta.epa.gov.tw/report/project.htm
http://sta.epa.gov.tw/report/project1.htm

2. 環保署"開發環境中奈米物質量測及特性分析技術" 期中報告 pdf 檔 (如附件)
(一般生需以環境奈米物質的問題為報告內容)

3. 勞工安全衛生研究所季刊
http://www.iosh.gov.tw/seasnpap.htm

4. 美國環保署查詢
www.epa.gov




光化學煙霧(PAN)

Photochemical smog光化學煙霧
由自然界產生或交通工具排放之不飽和碳氫化合物(如烯、炔或環狀烃等)在大氣環境中停留時間,因受強烈陽光之照射而發生光化學反應,生成具有強烈刺激性之衍生污染物,其多半為強氧化劑,例如:過氧硝酸乙醯酯(PAN, Peroxyacetyl nitrate)、過氧苯硝酸酯(PBN, Peroxyacetyl nitrate)和臭氧(O3),對人體之眼睛及黏膜等脆弱組織有強烈之刺激作用。

陽光(hv)
NO2(g) + O2(g) + 碳氫化合物 ------------->CH3CO-OO-NO2(g)

PAN(Peroxyacetyl nitrate) 過氧硝酸乙醯酯
CH3CO3NO2,為光化反應時,碳氫化合物與氮氧化物之產生,主要是醯基自由基和NO2結合生成,PAN氣體為微褐色,有異味,若植物嫩葉露於PAN 15~20ppb下4小時內,葉片會受損,對人類之眼睛鼻子及喉嚨有極大之刺激性。

資料來源:石濤, 環境化學, 2005, pp.10-24~10-25

Saturday, March 15, 2008

英文解釋名詞


英文解釋名詞
請利用這個地方, 將已知的英文名詞解釋加進來, 可利用comment方式加, 我們會將提供的名詞一直加進來...表現佳者加0.5 至3分..

solar spectral irradiance-- 太陽幅射能譜, 每單位波長的太陽幅射能量強度, 單位為 w/m2-micrometer.

albedo--太陽短波幅射經由地表, 雲及空氣分子反射至外太空的反射率, 全球平均反射率為0.3

黃日輝 said...臭氧洞Ozone hole:定義:並不是指大氣中有一個破洞,也不是指臭氧洞中一點臭氧都沒有,而是指大氣中臭氧總量減少到200個道布森單位(Dobson Units)以下,才稱為出現了臭氧洞。另一簡單定義為臭氧量減少達50%即視為臭氧洞。

11:01 PM 黃日輝 said...光分解的量子產率 Quantum yield(Φ,Y):又稱量子產額,為光化學反應的重要基本量之一。 光分解的量子產率一般用φ表示,如下所示:φ =進行光分解的激發態原子數 / 吸收光子數(或激發態原子數)

黃日輝 提到...碳氫化合物(非甲烷) Hydrocarbon (Non-methane) (NMHC)在正常大氣條件下,大都以氣態存在,為產生臭氧和其他光化學空氣污染物的前驅物質。 NMHC有甲烷的烷類, 稀類, 炔類, 芳香族, 醛類, 酮類等7:05 AM

黃日輝 提到...氮氧化物NOX = NO + NO2 反應性氮氧化物NOY (HNO3 , HONO, NO3, N2O5, HNO4, PAN and other organic nitrates, etc.)The NOY includes NOX11:01 PM Post a Comment

Dobson unit--Dobson:大氣層空氣柱中(地表往上約60公里)的O3, 被壓縮成O3分壓為1大氣壓273K下的空氣柱厚度為0.01mm時,O3的總量稱為 1個Dobson。一般來說大氣層的O3的平均空氣柱積分總量約為300 Dobson。A dobson unit is the most basic measure used in ozone research. The unit is named after G.M.B. Dobson, one of the first scientists to investigate atmospheric ozone (~1920 - 1960). He designed the 'Dobson Spectrometer' - the standard instrument used to measure ozone from the ground. The Dobson spectrometer measures the intensity of solar UV radiation at four wavelengths, two of which are absorbed by ozone and two of which are not.The illustration above shows a column of air, 10 deg x 5 deg, over Labrador, Canada. The amount of ozone in this column (i.e. covering the 10 x 5 deg area) is conveniently measured in Dobson Units.If all the ozone in this column were to be compressed to stp (0 deg C and 1 atmosphere pressure) and spread out evenly over the area, it would form a slab approximately 3mm thick.1 Dobson Unit (DU) is defined to be 0.01 mm thickness at stp; the ozone layer over Labrador then is ~300 DU.--蔡春進cjtsai@mail.nctu.edu.twhttp://www.nctu.edu.tw/~cjtsai
posted by CJ Tsai at 4:13 AM 0 comments links to this post

psc
張超鈞:PSCs:Polar Stratospheric Clouds 極地同溫層雲冰晶上的表面異相反應將增加臭氧(ozone)的消耗。極地的同溫層雖然乾燥,但是因為低溫很低會使水蒸汽凝結成為冰晶,形成極地同溫層雲(PSCs)。南極地區比北極溫度低,極地旋渦會比在北極來得穩定,較易形成PSCs。 而PSCs被區分為兩類型,亦即所謂的Type I與Type II。Type I分為Type Ia與Type Ib.Type Ia組成為HNO3.3H20(NAT), 溫度~190-195 KType Ib組成為HNO3/H2SO4/H2O, 溫度~190-195 KType II PSCs為極低溫直接由水結成之冰晶,組成為H2O ice, 溫度~188-190 KPSCs表面上的異相反應使得活性低的氯暫存物種變成活性的氯氣,Cl2經過光分解後形成破壞臭氧的氯原子,致使臭氧洞(ozone hole)產生,其反應機制如下: HCl(s)+ClONO2 ---> Cl2+HNO3(s)Cl2+hν ---> 2 Cl2【Cl+O3 ---> ClO+O2】ClO+NO2+M ---> ClONO2+MNet:HCl(s)+NO2+2O2 ---> ClO+HNO3(s)+2O2南極PSCs較易形成,較容易產生臭氧洞。Polar stratospheric clouds(PSCs)are important components of the ozone depletion process in the polar regions of Antarctica and the Arctic. PSCs provide the surfaces upon which chemical reactions involved in ozone destruction take place. These reactions lead to the production of free chlorine and bromine, released from CFCs and other ozone depleting chemicals(ODCs), which directly destroy ozone molecules.Polar stratospheric clouds(PSCs), also known as mother-of-pearl or nacreous clouds, have been observed for many years. As their name suggests, the clouds form in cold polar stratospheric winters where, despite the dryness of the stratosphere, the temperature drops low enough for condensation to occur. PSCs are believed to be made of nitric acid and ice. In other parts of the world the stratosphere is too warm for these clouds to form, which is one reason why the "ozone hole" is confined to the Antarctic region.Atmosphere, Climate & Environment Good Website:http://www.ace.mmu.ac.uk/http://www.ace.mmu.ac.uk/eae/Ozone_Depletion/Older/PSCs.htmlhttp://www.ace.mmu.ac.uk/eae/Ozone_Depletion/ozone_depletion.html5:45 AM
posted by CJ Tsai at 4:11 AM 0 comments links to this post