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Environmental Science

Gagandeep Saluja 01/16/2008 Human Health and the Environment Lecture 2: Airborne Hazards and Human Health Announcements The final is going to be cumulative. Professor does not yet know of the midterm date. She will post it on the intranet as soon as she gets information on it. The midterm examination will most likely be after the reading week but not 100% guaranteed. The professor’s new office hours are 4PM-6PM Wednesday before lecture in SW410. Change in Teaching Assistant Wing-Shun Wu for P-Z online lecture (LEC 60) Office Hours Friday 12PM-2PM Announcement on Readings  Book and presentations are enough for the exams  Only the topics that the professor covers in class look through the text, otherwise there is nothing additional Airborne Hazards • Today we will discuss two types of air pollutants 1) Outdoor air pollution 2) Indoor air pollution • What are the major sources of air pollution? They are natural and manufactured • Natural include forest fires, volcanoes – most of them that we cannot avoid • Manufactured has different kinds of industry and the burning of fossil fuels Outdoor Air Pollution • Listed are 6 common air pollutants • They are regulated by the U.S. Act – it is called the Clean Air Act of U.S.A. • A strict threshold is placed on these six pollutants • Discuss pollutants that are not regulated in Canada or U.S. as they still represent a hazard to human health Ozone • Is a chemical gas that has three oxygen atoms combined • There are two different types of ozone • One is good ozone – ozone layer in stratosphere protects us from harmful ultraviolet (UV) radiation • There are ozone holes and problems with the pollution (is the good ozone) and this ozone is not formed on ground level • It is formed in the upper level of atmosphere • What is the subject of concern is the ground level of ozone – ozone formed just a little bit above the ground and how this ozone is formed • Volatile Organic Compounds (VOC) react with Nitric Oxides (NOx) and with some effect of heat and sunlight (this is actually photochemical reaction) • Photochemical Reaction is any chemical reaction that is triggered by light, sunlight Life Support EESA10H3 S Gagandeep Saluja 01/16/2008 • When heat and sunlight has effect on the formation of ozone we can discuss where is the higher risk of being poisoned or having adverse effect of human health on these gas • Hot, warm, sunny climates are a big problem for these types of photochemicals, photochemical oxidants – i.e. Mexico City • We all know that Mexico City receives a lot of sunshine because of its warmer climate • In Los Angeles there is also a big problem with photochemical smog • In cold climates the problem is not that, it is less significant • In the morning and in the evening the concentration is lower • In the middle of the day especially around rush hour when traffic is heavy heat is higher and sunshine is combined with pollution thus the concentration of ozone increases significantly • Ozone is a summertime pollutant even in Toronto or in Canada – contamination and pollution with the ozone is much higher during the summer • Ozone is transported over very long distances – it doesn’t matter where it is formed (can be formed in Asia or Europe but can affect us here in North America) • What does the ozone do to our health, to our bodies? It causes lung damage (we call it lung disease) affect small airways which means in the lower levels of our lungs some changes and some problems can be seen • This results in shortness of breath, chest tightness (pressure on the chest), awful cough, nausea and can irritate and damage eyes, nose, sinuses, throat • But we believe that if we go outside if you exercise you will get healthy and probably more resistant and not be such a burner about today’s chemical • Scientists and experts found something very interesting that people that exercise outside a lot are more vulnerable • It is logical because many urban people exercise on the street to gather with the emissions and gases and they breathe deeper, take in much more air in their lungs Particulate matter (PM) • What is the particulate matter in air? Particles found in the air • Particles can be solid particles or can be liquid particles – aerosols • These particles vary significantly in size from really large with black soot (sticky tack material) – i.e. smoke that is somewhat very visible to very tiny particles of liquid aerosols • That is why we often find in literature particles and PM10 and PM2.5 – What does this mean? • PM 2.5 - particles smaller than 2.5 microns • Experts believe that these particles are small enough to be transported in lower level part of your lungs in the narrower airways because they are so small they can hurt your lungs on very small alveoli’s • Bigger particles will stay in upper level - nose, a little bit in the mouth (in the upper level of the respiratory system) • Major source of particles (particulate matter) are vehicles, vehicle exhaust, factories, different types of industry, construction sites (demolition, reconstruction), stone crashing, or burning emit soot and smoke Life Support EESA10H3 S Gagandeep Saluja 01/16/2008 • But not all particle matter is emitted as some is formed in the air • Serious health effects, why? These particulate matter can be associated with acidic material – acids as these acids damage the lungs a lot (very dangerous to our lungs) Carbon Monoxide • Why does carbon monoxide need more discussion and attention? • You are exposed and it is very hard to know that you are poisoned but it is also a very common pollutant • It is everywhere in outside pollution, outside air, also indoor – big problem indoor • Both critical for indoor pollution as well as for outdoor pollution • Odourless, colourless gas – emitted during the burning process but incomplete burning, burning of fossil fuels – anything that has carbon as a content and if it is partially burned process is not finished until end when emits carbon monoxide • Couple of examples include heaters indoor, woodstoves, gas stoves, fireplaces (poorly ventilated thus carbon monoxide can spread), water heaters, automobile exhaust, tobacco smoke • 1,000 people die each year in U.S. as a result of CO poisoning • If someone is exposed to the lower dosage of carbon monoxide not something very visible right away • For a longer time especially for a fireplace that is not ventilated you want experience for an significantly adverse amount of time but what might happen is you might have symptoms similar to the flu or similar to food poisoning (vomiting, dizziness, nausea something like that) • Many physicians get confused as it is hard for them to determine/detect what is going on if you don’t give them some clue (usually you don’t know) • Some people are even more vulnerable – infants, elderly, and people that already have problems such as heart and respiratory illnesses before that • They experience adverse effects in much lower concentrations than other healthy people – are at a higher risk Health effects of Carbon Monoxide • What does carbon monoxide actually do and why do we experience that adverse affect? • Carbon monoxide interferes with delivery of oxygen because carbon monoxide has a much higher affinity for hemoglobin (part of our blood, red in colour) • About two hundred or even more than two hundred times higher affinity for hemoglobin than oxygen • As a result of this we can experience some health problems – problems include fatigue, detected or undetected (that we do not know reason for) headaches, some weaknesses • When a concentration increases in the air then symptoms get worse as there is confusion, disorientation – i.e. we usually don’t know that we are poisoned and when we realize that we can leave the room or the car because of disorientation and that confusion – loss of coordination (cannot open the door) • We definitely need fresh air but we cannot leave the car – this is why carbon monoxide is such a dangerous chemical Life Support EESA10H3 S Gagandeep Saluja 01/16/2008 • If the concentration is increasing this poisoning can result in death, definite death Prevention • What to do, how to try to solve the problem? • A couple of informed tips to try to solve the problem – never leave the car engine running in a shed or a garage (you have definitely heard about that) because it results in carbon dioxide poisoning • Proper selection, installation, and maintenance of different appliances (heaters as such) • And of course , good use of these appliances – read instructions • Good ventilation – definitely all houses and apartments need good ventilation to avoid these kinds of problems • Use CO detectors – you should have them in your homes, apartments, rooms • Have to check batteries regularly and make updates as needed Nitrogen oxides (NOx) • Is a common name for a group of the nitrogen gases – they have nitrogen and oxygen and different number of atoms of oxygen • They are formed in many types of combustion process – not very much in industries but mostly in combustion process • These nitrogen oxides are involved in formation of ozone – it is also an important characteristic • How are solid particles formed from the nitrogen oxides? We say that it is a gas – usually in the air these nitrogen oxides react, they change • They can react and form aerosols for example with some carbonate or with some ammonia and form ammonia nitrate or ammonia sulfate or ammonia chlorate – those are hard solid particles of aerosols • Also can affect formation of acid rain or acidic depositions • It is not very much dissolving water but still is partially dissolving of water and thus as a result of that some acids are formed • It is also transported over very long distances same as ozone • This means it can be formed in some other place thousands of kilometres away but still affect our health Sulfur oxides (Sox) • Are emitted during the combustion process • Combustion process – burning process, any type of burning is the major source of air pollution • Burning, different kinds of burning but not only burning of the coal and oil • What kind of burning of the coal emits the highest level of sulfur oxide? Something that we call soft coal • That soft coal has a very high level of sulfur and when it is burned it emits sulfur gases into the air • Also when the gasoline is produced from the crude oil huge amount of sulfur dioxide and other sulfur gases are emitted • Many different types of ore used for extraction of for example copper or lead and many other metals can also contain high levels of sulfur Life Support EESA10H3 S Gagandeep Saluja 01/16/2008 • During the process of extraction of this metal sulfur gases, sulfur oxides are emitted into the air • Sulfur dioxide is different from nitric gases because it dissolves very easily in water – it even dissolves into water vapour in the air and form acids • What is the common sulfur acid that you know? Sulfuric acid – that sulfuric acid is actually acid rain coming back as acid deposition and causes environmental problems in ecosystems • This sulfuric acid can react with other particles – suspended particles in the air and form some sulfates, solids, salts • Also can be transported over very long distances and cause respiratory illnesses • Respiratory diseases – tightness, shortness in breath, often cough problems with the throat, runny nose • More dangerous diseases are on the heart – enlargement of the heart and aggravates existing heart diseases Lead • Where can we often find lead? Leaded gasoline (we do not use that much anymore) • In the past, 20 to 30 years ago we only had leaded gasoline but now not that much yet it is still the problem because in some other countries it is still very common • Lead is metal – then because we know that we can find that in gasoline • W
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