Air Quality Flashcards
(35 cards)
Globally, how many premature deaths can be attributed to ambient air pollution and how does air pollution rank as a risk factor?
Globally, 4.5 million premature deaths can be attributed to air pollution and air pollution ranks as the 5th highest risk factor for premature death.
How does air pollution affect human health?
Air pollution can contribute to a premature death due to damage caused in the cardiac and respiratory system.
What factors can influence LOCAL air quality?
Proximity to power plants, highways, industry, and mountains significantly influence local air quality.
What factors influence REGIONAL air quality?
Global air circulation patterns, latitude, and air temperature profoundly influence regional air quality.
What are the roles of scientists and engineers in regard to air quality?
Scientist and engineers calculate the amount of pollutants emitted from a point source, they analyze how those pollutants may be transported to expose a population downwind from the the source. They can also help to determine what health effects may be incurred by the exposed population and what technologies may be used to reduce emissions and exposure.
What is the composition of clean air?
Clean air is made up primarily of nitrogen (78.08%), oxygen (20.95%), and argon (0.93%). The remaining components of the air that are of concern as environmental pollutants are present in quantities of less than 1% in the atmosphere.
How is an air pollutant classified?
Any chemical or substance that is present in the atmosphere in quantities that negatively impact human health, the environment, and the economy, or unreasonably interfere with the enjoyment of life, property, or recreation.
What are some sources of pollutant emissions?
Pollutants are emitted as a result of processes producing energy for heat, work, or electricity. As a result, growing cities, climate change, population growth, and an increase in demand for energy have resulted in poor air quality in many locations.
What are some important aspects of the Clean Air Act of 1963 and 1970?
- The Clean Air Act (CAA) of 1963 was the first federal act in the United States to allow regulations for the control of air pollutants.
- The CAA of 1970 was the first comprehensive step by the federal government to limit emission of air pollutants from both stationary and mobile sources (i.e. buildings and vehicles).
- The 1970 CAA also established National Ambient Air Quality Standards (NAAQS).
What are the National Ambient Air Quality Standards (NAAQS)?
The NAAQS are goals set to achieve reasonable air quality in all regions of the United States. The 1977 CAA Amendments focused on improving air quality in regions where the concentrations of pollutants in the air were found to be higher than the target goals of the NAAQS. In 1990, the program was expanded to bring regions into compliance with the NAAQS, set more stringent standards for new sources, and included provision for stratospheric ozone protection.
What does the CAA (Clean Air Act) require of regions that are either above or below the NAAQS?
The CAA requires all regions in the Unites States to develop Prevention of Significant Deterioration (PSD) standards to maintain air quality in regions that are in compliance with the NAAQS. However, if a region is not in compliance, the CAA requires that it develop a State Implementation Plan (SIP) to improve air quality.
What are ‘primary pollutants’?
These pollutants have demonstrable negative effects on human health.
NAAQS are defined for (6) Carbon monoxide, Lead, Nitrogen dioxide, Ozone, Particulate Matter (PM2.5 & PM10), and Sulfur Dioxide.
What are ‘secondary standards’?
Secondary standards are required for air pollutants that may have potentially negative environmental effects, including plant damage, decreased visibility, and architectural damage.
What is the Air Quality Index?
Developed by the Environmental Protection Agency, the air quality index (AQI) was developed to help communicate air quality trends to the public and to provide warnings to the public on days that a region is not in compliance with the NAAQS. The AQI relates daily air pollution concentrion for ozone, particulate pollution, NO2, CO, and SO2 to health concerns for the general public. AQI below or at 100 is fine, above is unhealthy, especially for sensitive populations.
Who cares about air pollution?
Cleaner air leads to better health and higher productivity for workers; AND better health saves money on medical expenses.
How exactly does air pollution affect human health?
Pollutants enter the body through the respiratory system. Acute (short-term) systems can affect those predisposed to adverse respiratory conditions. Chronic or long-term effects of exposure to air pollution can include chronic inflammation of the bronchial tubes, sustained airway constriction, or pulmonary emphysema (the condition resulting in shortness of breath due to the destruction of the alveoli membranes in the lungs).
What are some respiratory distress symptoms?
Hypoxia: caused by an inadequate supply of oxygen to the body
Hypercapnia: a condition that occurs when too much carbon dioxide builds up in the bloodstream causing distress
Constricted Airways: may lead to edema and secondary infections in the lungs
Damage Cell Tissue: prevents airways from transferring oxygen and CO2 from the blood stream, leading to necrosis and edema
Effects and explanation of carbon monoxide pollution
CO is similar in size and molecular mass to O2 and will replace oxygen in the bloodstream if present in the air at high concentrations. This reduces oxygen transport to the brain, organs, and muscles. As CO levels increase in the blood stream individuals experience headaches, reduced hand-eye coordination and can result in fainting, coma, and death.
A majority of carbon monoxide emissions are from mobile sources.
Effects and explanation of Lead pollution
Major emission sources of lead in the United States include lead smelters, ore and metal processing facilities, and aviation fuel.
Ingested dust form lead-based pain in older homes is one of the primary routes of lead exposure. Lead negatively affects the nervous system, kidney function, immune systems, and the oxygen-carrying capacity of the blood. Infants and children under the age of 5 are especially vulnerable to the neurological effects of lead exposure.
Effects and explanation of Nitrous Oxides (NOx)
NOx is formed from the emission of combustion processes from both mobile and stationary sources.
NOx contributes to the levels of ground level ozone and are linked to adverse human health effects.
NO2 is a known irritant to the alveoli after exposures of 30 min to 24hrs.
NOx in the air increases an individuals susceptibility to pulmonary infections.
NOx reacts with volatile organic compounds (VOCs) to form ozone in the presence of heat and sunlight.
What are primary and secondary pollutants?
A primary pollutant is emitted directly to the atmosphere and the original chemical form has negative impacts on people or the environment.
Secondary Pollutants (such as tropospheric ozone) are produced in the atmosphere via chemical reactions.
Describe the process of how tropospheric ozone forms.
Ozone in the troposphere forms on warmer days when the chemical precursors to ozone are prevalent. Gasoline and diesel engines emit VOC’s and NOx from automobiles. So, ozone concentrations are highest during the day and decreased in intensity in the evening ultimately stopping. However, NO2 concentrations increase and build back up in the evening when ozone formation ceases.
Ozone can also be transported long distances by wind which worsens air quality in rural areas.
Ozone in concentrations as low as 1ppm(v) constrict and irritate the airways in the lungs.
Effects and explanation of Particulate Matter
Particulate matter are very small airborne solid or liquid mixture that may contain acids, organic chemicals, soil or dust. Size of the particle is directly related to the particles potential to cause negative health effects.
The EPA groups PM into two categories: PM10 and PM2.5.
PM10 is between 2.5 and 10microns in size, an example could be dust.
PM2.5 are 2.5 microns in diameter and are referred to as fine particles. An example could be particles emitted from forest fires.
Exposure to PM can lead to airway irritation, difficulty breathing, decreased lung function, aggravation of asthma, irregular heartbeat and heart attacks.
Effects of PM on the environment include reduced visibility, increased sedimentation in water bodies, depletion of nutrients in the soil.
Effects and explanation of Sulfur Oxides
Fossil fuel combustion accounts for 73% of Sulfur Oxides (SOx) emissions. Other industrial sources account for 20% of SOx emission. Sulfur oxides are highly soluble and are absorbed in the upper respiratory system where they irritate and constrict the airways. SOx is significantly more harmful when it absorbs particulate matter forming an an aerosol.
