LESSON13June2021_AP.pptx

Chapter 13: Air Pollution

Learning Objectives
Identify the role of air pollution as a major contributor to adverse human health conditions, from asthma to cardiovascular disease to premature death.

Identify ambient concentration of an air pollutant in a particular location depends on many factors, including emission sources, weather and land pattern.

Infer air quality management strategies include controlling emission at source, reducing the volume of emissions, and decreasing population exposure.

History of Air Pollution
Since human beings discovered fire, they began to pollute the air.

At first, air pollution was a local problem resulting from the smoke from kilns, hearths, and furnaces.

However, with the rise of industrialization and the development, air pollution has become a global problem.

It came to the forefront of public attention in the form of severe and fatal episodes, such as that of Donora, PA and the Meuse Valley in Belgium and London Smog.

The causes of the incident are difficult to identify conclusively, nevertheless, there are several obvious possibilities. Residents, such as Mrs. Lois Bainbridge, who wrote to Governor James T. Duff about the situation, stated that people in the area had complained for years abut the industrial pollutants that “eats the paint off your houses” and prevents fish from living in the river. Indeed, an investigation supervised by the director of the state government’s Bureau of Industrial Hygiene revealed an extraordinarily high level of sulfur dioxide, soluble sulphants, and fluorides in the air on October 30 and 31. According to the agency’s report and complaints by residents, such contamination of the atmosphere was caused by the zinc smelting plant, steel mills’ open hearth furnaces, a sulphuric acid plant, with slag dumps, coal burning steam locomotives, and river boats also contributing to the problem. On October 30 and 31, 1948, atmospheric conditions in the vicinity of Donora, Pennsylvania, contributed to the deaths of nineteen people within a 24-hour period.

Meuse Valley in Belgium: The first acute air pollution episode was obs erved in Meuse Valley of Belgium in 1930. There were 4 coke ovens, 3 steel mills, 4 gla
ss factories, and 3 zinc smelters along the 15 miles of the narrow valley of the Meuse river from Huy to Liege. A temperature inversion affected this valley from 1st until 5th December 1930, which confined the pollutants emitted from these plants and increased the concentrations of air pollutants. On the third day of this temperature inversion, approximately 6000 residents in the valley became ill with respiratory disease. Sixty had died before the week was over, and there were many deaths of cattle.

London: About 4,000 people were known to have died as a result of the fog, but it could be many more. Many people suffered from breathing problems
Press reports claimed cattle at Smithfield had been asphyxiated by the smog. Travel was disrupted for days. The weather in November and early December 1952 had been very cold, with heavy snowfalls across the region. To keep warm, the people of London were burning large quantities of coal in their homes. Smoke was pouring from the chimneys of their houses. Under normal conditions, smoke would rise into the atmosphere and disperse, but an anticyclone was hanging over the region. This pushes air downwards, warming it as it descends. This creates an inversion, where air close to the ground is cooler than the air higher above it. So when the warm smoke comes out of the chimney, it is trapped. The inversion of 1952 also trapped particles and gases emitted from factory chimneys in the London area, along with pollution which the winds from the east had brought from industrial areas on the continent.

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Donora, PA
On October 30 and 31, 1948, atmospheric conditions in the vicinity of Donora, Pennsylvania, contributed to the deaths of nineteen people within a 24-hour period.

The causes of the incident are difficult to identify conclusively, nevertheless, there are several obvious possibilities. Residents, such as Mrs. Lois Bainbridge, who wrote to Governor James T. Duff about the situation, stated that people in the area had complained for years about the industrial pollutants that “eats the paint off your houses” and prevents fish from living in the river. Indeed, an investigation supervised by the director of the state government’s Bureau of Industrial Hygiene revealed an extraordinarily high level of sulfur dioxide, soluble sulphants, and fluorides in the air on October 30 and 31. According to the agency’s report and complaints by residents, such contamination of the atmosphere was caused by the zinc smelting plant, steel mills’ open hearth furnaces, a sulphuric acid plant, with slag dumps, coal burning steam locomotives, and river boats also contributing to the problem.

London Smog
About 4,000 people were known to have died as a result of the fog, but it could be many more. Many people suffered from breathing problems . Press reports claimed cattle at Smithfield had been asphyxiated by the smog. Travel was disrupted for days. The weather in November and early December 1952 had been very cold, with heavy snowfalls across the region. To keep warm, the people of London were burning large quantities of coal in their homes. Smoke was pouring from the chimneys of their houses. Under normal conditions, smoke would rise into the atmosphere and disperse, but an anticyclone was hanging over the region. This pushes air downwards, warming it as it descends. This creates an inversion, where air close to the ground is cooler than the air higher above it. So when the warm smoke comes out of the chimney, it is trapped. The inversion of 1952 also trapped particles and gases emitted from factory chimneys in the London area, along with pollution which the winds from the east had brought from industrial areas on the continent.

London Smog

Clean Air Act
Following the air pollution related disasters:
Clean Air Act was enacted in UK in 1956
United States 1963- EPA promulgates National Ambient Air Quality Standards (NAQS) under the Clean Air Act

Air Pollution in the World’s Dirtiest Cities
The combination of vehicular traffic and industry—with ineffective regulation and uncontrolled emissions—has led to some of the highest pollution levels on the Earth.

In China, where air quality can be poor (Chan & Yao, 2008), urban air pollution levels routinely exceed World Health Organization (WHO) standards by an of magnitude of (Figure 13.1).

The Chinese government launched a “war on pollution” in 2013, and in 2014, the Chinese Environmental Protection Ministry announced that only eight of the nation’s seventy-four large cities had met official air quality standards (up from three the previous year).

Air Pollution in the World’s Dirtiest Cities
As shown in Figure 13.2, Indian cities have even higher particulate matter levels than do Chinese cities. Many other cities of Asia, Africa, and Latin America are similarly afflicted, and air pollution continues to rise in many regions of the world.

The health impacts of this pollution are severe. The 2010 Global Burden of Disease Study attributed over 3.2 million deaths, 3.1% of global disability-adjusted life years (DALYs), and 22% of ischemic heart disease DALYs to particulate matter (Lim et al., 2012); most of these occurred in the cities of developing nations.

By one calculation the average Indian in a polluted city would gain 3.2 years of life if urban pollution were reduced to legal standards (Greenstone et al., 2015).

A study of Mexico City, Santiago, and São Paulo estimated that air pollution control would avert over 156,000 deaths, 4 million asthma attacks, 300,000 children’s medical visits, and almost 48,000 cases of chronic bronchitis in those cities over a twenty-year period.

Air Pollution in the World’s Dirtiest Cities
Mexico City was the most polluted city on the planet in 1992, according to the United Nations, due to a combination of a large population, vehicular and industrial sources, practices such as trash burning, and challenging geographic and meteorological conditions.

The city lies in the high-altitude crater of an extinct volcano, where low atmospheric oxygen levels cause incomplete fuel combustion, intense sunlight drives ozone formation, and the topography helps form inversion layers that trap pollutants.

Months would go by without a single day of acceptable air quality. In the 1990s, the city initiated its PROAIRE program, combining regulatory, economic, technological, and behavioral approaches. Air quality has improved dramatically, and health benefits are expected to follow (Riojas-Rodríguez, Álamo-Hernández, Texcalac-Sangrador, & Romieu, 2014).

Air Pollution Estimates in 2016-UN
In 2016, PM2.5 exposure reduced global average life expectancy at birth by approximately one year.
Around seven million people die each year from exposure to polluted air, both indoor and outdoor. The three biggest killers attributable to air pollution are stroke (2.2 million deaths), heart disease (2.0 million) and lung disease and cancer (1.7 million deaths).

Ambient (outdoor) air pollution accounts for:
25 per cent of all deaths and disease from lung cancer
17 per cent of all deaths and disease from acute lower respiratory infection
16 per cent of all deaths from stroke
15 per cent of all deaths and disease from ischemic heart disease
8 per cent of all deaths and disease from chronic obstructive pulmonary disease

https://www.unenvironment.org/news-and-stories/story/air-pollution-know-your-enemy

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Air Pollution-UN
According to the World Health Organization’s air quality database, 97% of cities in lo-middle income countries with more than 100,000 inhabitants do not meet air quality guidelines. In high-income countries, the proportion is 40 per cent.

Delhi, India and Cairo, Egypt have the worst PM10 pollution levels out of the world’s megacities (over 14 million people), but Argentina, Brazil, China, Mexico and Turkey all have cities in the top-ten list of most-polluted places.

World Regional Capital City Ranking
Sorted by average yearly 2.5 concentration
-World Air Quality Report

World Air Quality Report

Types of Ambient Air Pollution
Air pollutants can be categorized by their source or by their physical and chemical characteristics.

An air pollutant may be either directly emitted (a primary pollutant) or formed in the atmosphere through the physical and chemical conversion of precursors (a secondary pollutant).

Another important feature of air pollution sources is whether the emissions are natural (biogenic) or the result of human activity (anthropogenic).

Additionally, air pollutants differ in their physical form; they can be either gases or particles.

A final way of classifying air pollutants relates to the way they are legally regulated. Some are criteria pollutants (the major pollutants, including carbon monoxide, lead, nitrogen, etc.), and others are hazardous air pollutants, which include a number of volatile organic chemicals, pesticides, herbicides, and radionuclides.

Studies on Air Pollution and Health
Epidemiological studies investigate the relationship between air pollutant concentrations and health outcomes under the real-world conditions of exposure, typically in large populations in community settings.

Herein, data on pollutant concentrations are obtained by air monitoring, and used as measures of individual exposure.

However, epidemiological studies can potentially be limited by the inability to control for other factors, referred to as confounding factors, such as temperature, weather, population characteristics, and pollutants other than those being investigated, and by the difficulty of accurately estimating personal exposure.

Controlled human exposure studies correct for possible confounds, and involve exposure of volunteers to a specified concentration of a particular air pollutant or pollutant mixture in a laboratory setting and then measurements of their health responses.

Animal studies involve exposures on a short- or long-term basis to a pollutant or to a pollutant mixture under well-characterized conditions. Animals are some- times exposed to outdoor pollution and even placed at sites of particular interest, such as along roadways. Generally rodents are used for such experiments, but dogs and primates have also been studied.

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Sources of Air Pollution
There are many sources of air pollution, including particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds, tropospheric ozone, carbon monoxide, lead, and mercury.

Particulate Matter
Particulate matter (PM) refers to a generic class of pollution rather than to a particular, individual pollutant with a specified chemical structure.

PM includes solid or liquid particles suspended in air, regardless of their chemical composition.

The composition of PM differs by geographic area and can vary with season, source, and meteorology.

PM results from the burning of fuel (emissions from power plants), driving on unpaved roads, industrial activity, and wood-burning stoves, and from natural sources such as pollen, dust, salt spray, erosion, and mold.

PM can be either primary (directly emitted) or secondary (formed in the atmosphere through physical and chemical conversion of gaseous precursors such as nitrogen oxides [NOx], sulfur oxides [SOx], and VOCs

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Particulate Matter, con’t
Particles are generally categorized according to their size, using a measure called aerodynamic diameter. PM10 refers to particles with an aerodynamic diameter of 10 μm or less, whereas PM2.5, or fine PM, has an aerodynamic diameter up to 2.5 μm, and ultrafine PM particles have an aerodynamic diameter up to 0.1 μm. . Coarse PM (PM10–2.5) refers to particles with an aerodynamic diameter between 2.5 and 10 μm. Total suspended particles (TSP) refers to almost all particles in the air and is typically measured as particles up to about 45 μm in aerodynamic diameter.

Ambient levels of PM10 and 2.5, have been associated with health effects including increased hospital and emergency room admissions, respiratory symptoms, decline in pulmonary function, exacerbation of chronic respiratory and cardiovascular diseases, and premature mortality.

Particulate Matter- EPA
Revisions to the Clean Air Act in 1990 required each state to develop a State Implementation Plan (SIP).

Local monitoring of PM levels, strategies to reduce PM emissions, and steps to evaluate these strategies.

Recycling, using energy-efficient products and appliances, planting deciduous trees, and driving less.

Between 2000, when monitoring began, and 2007, average national levels of PM2.5 declined by 11%

PM10 declined by 28% between 1990 and 2007.

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Sulfur Dioxide
Sulfur dioxide, SO2, is a water-soluble gas that is produced from the combustion of sulfur-containing fuels and materials, such as coal and metal ores (a primary contributor to the London Smog).

Other sources are industrial boilers, trains, ships, and metal-processing facilities; along with household use.

SO2 can be converted to sulfuric acid, and therefore contributes to acid deposition, which harms vegetation, other materials, and wildlife. SO2 also contributes to the formation of particulate matter.

Because SO2 is highly soluble in water, most inhaled SO2 is absorbed by the mucous membranes of the upper airways with little reaching the lung.

SO2 exposure has been associated with reduced lung function, bronchoconstriction (increased airway resistance), respiratory symptoms, hospitalizations from cardiovascular and respiratory causes, eye irritation, adverse pregnancy outcomes, and mortality.

Difficult to attribute these reported associations to SO2 itself, because it is a precursor to particulate matter and generally exists as a component of a complex, combustion-related pollutant mixture.

However, it is difficult to attribute these reported associations to SO2 itself, because it is a precursor to particulate matter and generally exists as a component of a complex, combustion- related pollutant mixture.

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Nitrogen Oxides
Nitrogen oxides, NOx, make up a category of highly reactive gases containing nitrogen and oxygen, such as nitrogen dioxide (NO2) and nitrogen oxide (NO).

NOx are produced through combustion, including fossil fuel combustion, when the nitrogen that constitutes almost 80 percent of air is oxidized. Ex: cars, trucks and buses, power plants, and off-road equipment (EPA).

Like ozone, NO2 is nearly insoluble in water and can reach the lower respiratory tract.

Health effects of NO2 include irritation of the eyes, nose, and throat at higher concentrations; short-term decreases in lung function; and possibly increased respiratory infections and symptoms for children.

Volatile Organic Compounds
Volatile organic compounds (VOCs) are a category of organic chemicals with a high vapor pressure, which readily evaporate at normal temperature and pressure.

They include benzene, chloroform, formaldehyde, isoprene, methanol, monoterpenes, and hundreds of additional compounds.

VOCs originate from natural sources (primarily vegetation such as oak and maple trees); industrial processes involving such things as chemical processing, use of solvents, and power generation; and transportation, including motor vehicles and off-road transportation sources such as aircraft, construction equipment, and lawn mowers.

Transportation accounts for nearly half of VOCs, and motor vehicle emissions (especially from older, poorly maintained vehicles) represent about 75% of that amount.

VOCs are precursors of ozone but also have independent health effects, including irritation of the respiratory tract, headaches, and carcinogenicity.

Tropospheric Ozone
Ozone (O3 ), a gas, is present in the troposphere, the lowest atmospheric layer, which extends from the Earth’s surface to the stratosphere.

Stratospheric ozone forms the naturally occurring ozone layer that protects us from ultraviolet radiation, whereas tropospheric ozone, sometimes called ground-level ozone, is a harmful pollutant.

Tropospheric ozone is a colorless gas and a photochemical oxidant formed through complex, nonlinear chemical reactions involving the precursors VOCs and NOx in the presence of sunlight- thus referred as photochemical smog.

Ozone is not highly soluble in water and can thus reach the lower respiratory tract.

Ozone, con’t
Because of its oxidant properties, ozone can break molecular bonds and rapidly damage human tissue. Short-term exposure to ozone for healthy adults has been associated with temporarily decreased lung function, increased airway resistance, and increased respiratory symptoms, such as coughing and wheezing.

These changes are reflected by increases in clinic visits, emergency room visits, school absenteeism, and hospitalizations following high-ozone days.

Asthmatics are particularly susceptible to health problems associated with ozone exposure.

Carbon Monoxide
Carbon monoxide (CO) is a colorless, odorless gas formed by incomplete combustion of carbonaceous material, such as gasoline, natural gas, oil, coal, tobacco, and other organic materials.

People are exposed to CO through inhalation; CO is rapidly absorbed into the bloodstream through gas exchange in the lungs. A common pathway for CO exposure is cigarette smoking; regular smokers can have blood CO levels over twenty times higher than background atmospheric CO levels. Indoor exposure to CO occurs mainly through the use of gas-powered appliances or internal combustion engines in confined or unventilated areas.

When CO enters the bloodstream, it binds to hemoglobin, displacing oxygen, and forms carboxyhemoglobin (COHb). With rising COHb levels, the ability of hemoglobin to deliver oxygen to the tissues is disrupted. The tissues most sensitive to hypoxia are those most affected, leading to cardiovascular, respiratory, and neurological toxicity.

People exposed to low CO levels for a short time may experience fatigue, headaches, nausea, dizziness, disorientation, and visual and coordination impairment. At higher levels or longer exposures, CO can cause angina (chest pain), severe impairments in vision and cognition, and even death.

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Lead
Historically, lead in ambient air came largely from leaded fuel, that is, fuel with lead added as an antiknocking agent.

Most countries have already phased out leaded gasoline or have plans to do so. In these areas, nonairborne sources of lead, such as ingestion of leaded paint, are a larger health concern than airborne lead.

Lead can be harmful even at low doses because it accumulates in the body, mostly in the bones.

Exposure to lead can cause damage to the nervous system and kidneys and can interfere with red blood cell formation, reproductive function, and gastrointestinal function.

1. (Automotive Engineering) a compound, such as lead tetraethyl, added to petrol to reduce knocking in the engine
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Mercury

Mercury is a heavy metal found in the environment in three forms, elemental, inorganic, and organic, each with unique chemical and toxicological properties.

The chemical properties of elemental, inorganic, and organic mercury make these substances suitable for many commercial applications. Throughout the nineteenth and early twentieth centuries, mercury nitrate was used in the production of the felt used by milliners. Today, mercury is used in electronics, batteries, thermometers, and medical equipment.

Mercury naturally contaminates fossil fuels, especially coal, so fossil fuel combustion releases mercury into the environment. Coal-fired power plants account for about half of airborne mercury emissions in the United States and globally—the largest source. It is estimated that the concentration of mercury in the air has increased three- to sixfold since the industrial revolution began.

Because mercury bioaccumulates in tissues, fish can have high concentrations of mercury, especially those higher in the food chain, such as shark, swordfish, and king mackerel; this can then be passed on to people when they eat mercury- contaminated fish.

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Mercury
After atmospheric deposition, mercury enters the ecosystem and is widely circulated. People are exposed to mercury through oral, inhalation, and dermal exposure.

When people eat large, predatory fish such as tuna, swordfish, and king mackerel from contaminated bodies of water, they ingest mercury.

High-level exposure to mercury is rare; however, it can lead to severe neurological impacts, including loss of senses, unconsciousness, and even death. More common are low-level, chronic exposures. These types of exposures are most concerning in young children, pregnant women, and women of childbearing age. Because mercury remains in the body for years following exposure, mercury exposures that occur prior to conception affect the developing fetus.

Exposure to low levels of mercury during development is associated with neurological dis s including developmental delays. High-level prenatal exposure to mercury is associated with mental retardation, deafness, blindness, cerebral palsy, and congenital malformations.

Methylmercury- EPA
For fetuses, infants, and children, the primary health effect of methylmercury is impaired neurological development.

Methylmercury exposure in the womb- result from a mother’s consumption of fish and shellfish that contain methylmercury, can adversely affect a baby’s growing brain and nervous system.

Impacts on cognitive thinking, memory, attention, language, and fine motor and visual spatial skills have been seen in children exposed to methylmercury in the womb.

Recent human biological monitoring shows that most people have blood mercury levels below a level associated with possible health effects.

Outbreaks of methylmercury poisonings have made it clear that adults, children, and developing fetuses are at risk from ingestion exposure to methylmercury.

Air Toxics
Hundreds of other ambient air pollutants exist besides those just described.

They include hydrochloric acid, captan, parathion, naphthalene, biphenyl, vinyl bromide, methyl bromide, dioxin, and cadmium.

Exposure to these pollutants can occur through inhalation, but they also enter other environmental media such as water and food.

Health effects of these air toxics include damage to the neurological, immune, respiratory, and reproductive (for example, reduced fertility) systems, as well as developmental problems and some cancers.

Air Pollution Prevention And Control
Air quality management approaches include controlling emissions at the source, by such means as scrubbers at coal-fired power plants; reducing the volume of emissions, by such means as increased use of public transportation to lower vehicular air pollutants or emissions controls for automobiles; and decreasing population exposure.

Reduction of the health effects of air pollution comes from actions at multiple spatial and institutional levels, ranging from personal decisions by individuals, to community and state plans, and to multigovernment agreements.

EPA’s Air Quality Index, which provides a health warning on high air pollution days to encourage sensitive individuals to avoid the outdoors.

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New Delhi 2014

http://www.cnn.com/2016/11/06/world/new-delhi-air-pollution-school-closures/index.html

http://timesofindia.indiatimes.com/city/delhi/Air-pollution-Delhi-shuts-schools-bans-construction-work/articleshow/55273297.cms