Env 11: Air Pollution

What is a temperature inversion, and what effect do temperature inversions have on air pollution?

- usually, air becomes cooler as you move higher into the atmosphere (warm air near the surface is less dense, so it rises, taking much of the air pollution away with it) - HOWEVER, during a thermal inversion, this normal pattern switches. A pocket of cool air is trapped below a layer of warmer air, causing for air pollution to also be trapped in this pocket of air

What are primary and secondary air pollutants? Be able to name some of them.

1) Primary air pollutant - a harmful substance that is emitted directly into the atmosphere (ex. Carbon Dioxide, Carbon Monoxide, Methane, and Nitrogen oxide) 2) Secondary air pollutant - a harmful substance formed in the atmosphere when a primary air pollutant reacts with substance normally found in the atmosphere or with other air pollutants. (Ozone and Sulfuric acid)

What are some of the health effects associated with exposure to biomass burning?

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Who are the two primary populations affected by biomass combustion, and what are some specific health effects associated with each group?

Adults (mothers): chronic obstructive pulmonary disease (COPD), lung disease, cancer, blindness, TB, and heart disease Children: pneumonia, asthma, low birth weight, early infant death, cognitive impairment

How is biomass combustion harmful to human health?

Biomass combustion is very harmful to human health because it is incomplete - creates large amounts of toxic by-products which is inhaled (Carbon Monoxide and PM 2.5)

Ozone

Ozone is in the stratosphere where it plays an important role in protecting us from Sun's radiation. However, ozone can also exist in the troposhere (where we live) and once its there it is considered to be a pollutant because it can act as a respiratory irritant. Nitrogen oxide (NO2), another pollutant, reacts with ozone in raections

What are the sources of VOCs?

Sources of VOCs (volatile organic compounds) are paints, paint strippers, and other solvents as well as car exhaust

What did the Clean Air Act do? What are some environmental, health or economic benefits from the CAA?

The Clean Air Act (CAA) required the EPA to set and enforce limits for 6 criteria pollutants, considered to be the most significant to human and environmental health. ○Environmental, health, and economic benefits from the CAA. ○CAA was amended in 1990 to include acid rain, urban air pollution, and toxic air emissions. ○CAA encourages the use of market-based principles, pushed for use of cleaner fuels and promotes energy conservation.

Atmosphere

The earth's atmosphere is a very thin layer. We live in the troposphere which is only 4 to 12 miles thick. Air Pollution occurs in the troposphere. As discussed before, the atmosphere has several layers. The ozone layer lies within the stratosphere. We live in the troposhere (troposphere -> stratosphere -> mesosphere -> ionosphere)

Which size of particulate matter is the most threatening to human health?

The size of the particulate matter that is the most threatening to human health is less than 2.5 microns in diameter (labeled PM 2.5) - causing asthma and other related lung diseases. The smaller particles can penetrate deep into the lung.

Know the two primary designs of epidemiological studies used to investigate air pollution health effects.

Two primary epidemiological study designs: time series studies of acute effects and cohort/cross-section studies of chronic effects.

What are some commonly used biomass fuels?

dried leaf, cow dung and sea weed, wood, and hay

Smog

is a secondary pollutant, formed by sunlight reacting with air pollution. is composed of nitrogen oxides, volatile organic compounds (VOCs), ozone, and peroxyacytyl nitrates (PANs)

What are some health effects attributable to biomass burning?

○ Health effects attributable to biomass burning are non-communicable diseases including stroke, ischemic heart disease, chronic obstructive pulmonary disease (COPD), and lung cancer. ○ Over 4 million people die prematurely from illness attributable to the household air pollution from cooking with solid fuels (incomplete combustion) ○ Children account for half of those deaths (pneumonia).

What evidence was given to show that sulfuric acid/acid rain is decreasing?

○Acid rain decreased significantly as there were more controls placed on emitter of sulfur dioxide and nitrogen oxides, particularly coal burning plants ○Map shows USA in 1985 compared to 2008 - sulfate ion concentration went down dramatically in New England states.

Know why biomass is a low efficiency energy system (two factors).

○Biomass is a low efficiency energy system because it is not clean, convenient, and cheap, and commonly used among low SES communities.

What is the historical evidence that air pollution causes major health problems (Donora and London)

○Donora, an industrial town near Pittsburgh producing zinc metal from ore, had a lot of metal smelting plants which produces A LOT of pollution since these plants burned coal to generate enough heat to smelt and purify their products. Thermal Inversion occurred during the fall of 1948. A thick smog, with particulate matter and many toxic gases began to build. This lasted for five days and dissipated after a rainstorm. 20 people died and many were sick. US Steel and American Steel settled lawsuits but never took responsibility for it. ○In London 1952, was an unusually cold winter happened and people were burning more coal (high in sulfur) to keep warm. This caused a thermal inversion to settle over London as lots of emissions from thousands of chimneys began to build up. About 4,000 people died during the smog with thousands more becoming ill from upper respiratory tract infections. (Many people died even after the smog cleared - dying from chronic)

What are the challenges associated with studies on biomass exposure and health? Know some confounders in these studies.

○Everyone is exposed - its hard to define a control group ○Exposures are difficult and costly to measure ○Health outcomes are also difficult to measure, especially pneumonia ○Confounders - families that use dirtier fuels (high exposure) may be poorer than those using cleaner fuels (low exposure). Poor families may be generally less healthy, leading to potential positive bias in effect estimate. Poor families may be less likely to use a clinic when illness occurs, leading to potential negative bias in effect estimate.

In general terms how is ground level ozone created? Why is ozone called a secondary pollutant?

○Ground level ozone, a secondary pollutant, is formed by reacting nitrogen oxide (NO) and volatile organic compounds (VOCs) in the presence of sunlight. ○Nox+VOCs=O3 (baked in sunlight) ○Highest level of Ozone are often highest downwind of source regions ○Ozone is a strong oxidant that damages vulnerable cells deep in the lungs.

Name the six criteria pollutants

○Sulfur dioxide (comes from coal burning) ○Carbon monoxide (comes from vehicle exhaust - it is the most dangerous!) ○Particulates (small particles of dust, ash, soot which are inhaled) ○Ozone (a secondary pollutant) ○Nitrogen oxides (NOx comes from combustion of fossil fuels) ○Lead (Today we would add hydrocarbons in place of lead as a major pollutant since petroleum doesn't contain lead anymore)