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The Air We Breathe 200 4 . 9. Yongsik Lee. TIP For additional advice , Please visit www.ezchem.pe.kr. Spaceship Earth. Spaceship Earth. The Earth is a fragile spaceship with limited resources and reproduction capacity.
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The Air We Breathe2004. 9.Yongsik Lee TIP For additional advice, Please visitwww.ezchem.pe.kr
Spaceship Earth • The Earth is a fragile spaceship with limited resources and reproduction capacity. • The thickness of the biosphere is just 10 km - that's less than a thousandth of its diameter.
Your Piece of Land • The diameter of the Earth is roughly 12'756'000 m so it's surface is 5.112 x 1014 m2. • The human population in year 2000 is estimated to six billion (6 x 109) people. • This gives every person on Earth a piece of about 85'200 m2 which is a square of just 292 x 292 m. • Approximately 71% of the surface are covered with water so the remaining land is equal to a square of 157x157 m. • But remember that about 20% are covered with desert. Every food you eat must grow on this piece of land.
Your Water Ration • There are approximately 1.4 x 1018 m3 water on Earth, that's 2.3 x 108 m3 or a cube with 616 m side length for each person. • 97.2% of it are saltwater, • 2.14% are ice on the poles and in glaciers, • 0.001% are in the atmosphere and • 0.6% are drinkable freshwater, • so your water tank is a cube with 111 m side length. • Don't forget to share this water with other animals.
호흡하는 공기 • Air • Mixture of Nitrogen, oxygen and others
물질의 분류 • Heterogeneous mixture • Homogeneous mixture • solution • Substance • Compound • element
Concentration of a mixture • Solution is a homogeneous mixture • Solution = solute + solvent • Vol% = solute volume / solution volume • Wt% = solute wt / solution wt • mass% is correct but … • Ppm (part per million) • Ppb (part per billion) • Ppt (part per trillion) • 0.1 M NaOH 수용액 만들기
Inhaled and exhaled air • Table 1.1 • 산소는 체내에서 대사 과정을 통해 이산화탄소와 물을 생성한다. • 그러나 날숨의 물은 허파 내부 표면이 젖어 있어서이다. • 날숨에도 16 vol%의 산소가 있다. Mouth to mouth resuscitation 의 효과를 생각해보자.
Risk assessment • 과학적 자료를 평가하여 위험을 확률적으로 예측하는 과정 • 독성과 노출 • 물질의 본질적인 위험 • 접촉한 물질의 양 • 동물실험이나 역사적 결과의 통계처리
독성과 노출 - 일산화탄소 • Peanut butter carcinogen • 1/10,000 – 1/100,000
Air pollution • Complete Table 1.2 with air composition of Seoul • Permissible limits for 4 polluants • CO 9 ppm (8 hour average) • Ozone 0.12 ppm (1 hour average) • SOx 0.030 ppm (24 hour average) • NOx 0.053 ppm (yearly average)
ozone • Allotrope of oxygen (O2) • 자극성이 강한 독특한 냄새 • 반응성이 크고 호흡기에 악영향 • 성층권 오존은 자외선을 차단하여 생물체를 보호
NOx and SOx • 호흡 장애 물질 • 1952년 12월 런던 스모그로 4천명 사망 • 산성비의 원인
Air pollution source • 석탄의 연소 • 석탄은 불순물로 황을 1-3% 함유 • 연소하면 황은 이산화황으로 • 불순물 무기질의 재는 촉매작용 • Sox는 물과 만나면 황산 형성 • 내연기관 • 불순물 황은 미량이나 다른 모든 오염기체 생성 • 불완전 연소는 일산화탄소와 VOC 형성 • 노킹 방지제 tetraethyl lead
자동차 배기가스 오염 • Between 1970 and 1989 • CO emissions from vehicles in the United Kingdom increased by 74 % • NOx emissions more than doubled. • By 1993, road vehicles were the source of • 90 % of all emissions of CO • 49 % of all emissions of NOx.
Octane number • Octane number • Knocking characteristics • Measure of ability to burn smoothly in an internal combustion engine • Autoignition temperature • A liquid will ignite without a source of ignition • Low for straight-chain hydrocarbon • High for branched-chain • Gasoline (C5 – C12) needs a spark
One-cylinder test engine • Isooctane (100) vs. heptane (0) • % number of isooctane = octane number • Octane number 87-92 in USA • Pseudo-gasoline • Anti-knocking agent – tetraethyl lead • Octane enhancers – toluene, tert-butyl alcohol, MeOH, EtOH
Lead poisoning • Lead has no known biological function • No proven safe lower limit of lead • Lead is ubiquitous – cheap metal
Source of lead • Paint • Gasoline – tetraethyl lead (anti knocking agent) • Household dust • Ceiling dust • Pesticides (lead arsenate) • cigarette
Catalytic converter • It is a stainless steel box mounted in the exhaust system. • Inside is a catalyst on a ceramic or metallic support protected from vibration and shock by a resilient ceramic or metallic 'mat'. • The catalysts are combinations of platinum, palladium and rhodium.
Indoor air pollution • includes chemical sprays, household products such as paint strippers, cigarette smoke and various building materials. • Infectious agents such as viruses and bacteria may also be more concentrated indoors especially where overcrowding exists. • Sick Building Syndrome often results from air pollution especially in buildings with a lack of proper ventilation and fresh air. • Talbe 1-10
References • www.nies.ch/me/earth.html • www.time.com/time/ 2002/hybrid_car/ • http://www.schoolscience.co.uk/content/4/biology/abpi/asthma/asth2.html • Photolysis of the Carbon Monoxide Complex of Myoglobin: Nanosecond Time-Resolved Crystallography • http://www.lead.org.au/bblp/sld019.htm