mod 43-44 RQ smog + indoor air pollution

photochemical smog

• smog that is dominated by oxidants such as ozone. Also known as Los Angeles–type smog; brown smog

sulfurous smog

• Smog dominated by sulfur sulfur dioxide, sulfate compounds, and particulate matter. Also known as London-type smog; gray smog; industrial smog

economic effect of smog

economic harm since poor visibility = less tourism revenue and income for hotels and restaurants

why is smog a complex problem that can’t be solved easily

based on intensity/duration of sunlight, water, and VOCs

3 steps for the chemical process of photochemical smog

1. during the day, UV warms the atmosphere

2. lots of NOx (little VOCs) → splits into NO₂ and free oxygen O

3. energy from sun makes O combine with O₂ into ozone O₃

complete the relationship: as nitrogen dioxide increases…

ozone accumulates

when are nitrogen oxides and smog highest in concentration

• early morning

• mid/late afternoon

describe ozone destruction

even when sunlight intensity decreases, nitrogen oxide is still present, and the ozone combines with NO to make O₂ and NO₂

VOC chemicals do either what two things

evaporate

sublimate

evaporate

• The process of converting from liquid to a gas or vapor

sublimate

• The process of converting from a solid to a gas or vapor

list 4 sources of VOCs

trees/forest fires

gasoline

formaldehyde

formaldehyde

• naturally occurring compound used as preservative and adhesive in plywood and carpeting

how do VOCs prevent ozone destruction

combine with nitrogen oxide to a stronger bond and can’t combine with ozone, causing larger accumulations of ozone in urban areas and rush hour

how does temperature affect VOCs

emissions of VOCs and evaporation of liquid VOCs increase

NO emissions increases bc more cooling

4 impacts of VOCs on human health

• lung irritation

• aggravates existing respiratory conditions

• risk of infection

• itchy eyes

thermal inversion

• atmospheric condition in which a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below

inversion layer

• The layer of warm air that traps emissions in a thermal inversion (cities bc of exhaust n industry)

4 natural sources of pollutant compounds

volcanoes, lightning, fire, and plants (tree VOCs = smog mountains)

3 sources of PM spreading

• large agricultural field plowing (dust storms)

• volcanic ash

• forest fires

• PM₁₀

• Particles smaller than 10 μm are called Particulate Matter-10 and are not filtered out by the nose and throat and can be deposited deep within the respiratory tract

• PM_2.5

• Particles of size 2.5 μm and smaller can travel further within respiratory tract and are of even greater health concern

how does particulate matter concentration affect sunlight

• high concentrations after forest fires or volcanic eruptions can reduce solar radiation enough to limit photosynthesis

what causes haze

• light scattering by particulate matter, with ozone and photochemical oxidants also contributing indirectly to haze formation

4 sources of carbon dioxide

• anaerobic respiration

• aerobic respiration

• decomposition

• combustion

2 major natural global sources of carbon dioxide

• decomposition with or without oxygen and the combustion of biomass in fires

anaerobic decomposition formula

• sugar → carbon dioxide + methane + less energy

indoor air pollutants

Compounds that adversely affect the quality of air in buildings and structures

3 sources of indoor air pollutants

• combustion inside buildings

• off-gassing from building materials

• transfer of outdoor pollutants into indoor spaces

2 examples of indoor air pollutants shared w outdoor

• carbon monoxide and particulates

2 examples of indoor air pollutants mainly an indoor concern

• radon and asbestos

describe carbon monoxide poisoning 2

• extremely dangerous indoors

• binding to hemoglobin more effectively than oxygen and causing oxygen deprivation, headaches, dizziness, nausea, loss of consciousness, or death

carbon monoxide sources and risks in developed countries 2

• malfunctioning natural gas heaters or furnace exhaust systems → living spaces

• hard to detect esp during sleep → get detectors

carbon monoxide sources and risks in developing countries 3

• burning biomass in open-pit fires with little or no ventilation

• poor combustion and absence of exhaust systems make CO and particulate matter major hazards

• children at higher risk due to faster respiration rates

sources of smoke and soot

• fires inside or outside buildings, as well as tobacco smoke, are major sources of indoor particulate matter

effects of smoke and soot

• prolonged exposure can cause respiratory infections and cancer

• second-hand smoke exposes non-smokers to high concentrations of particulate matter, increasing health risks

what does household dust contain

• particulate matter, pollen, bacteria, and dust mite waste, fueled by human shedding

sources and effects of dust mites

• bedding, pillows, flooring, and carpets, and their body fragments and droppings contribute to asthma and allergic reactions

sources and effects of mold

• grows on damp organic matter indoors behind walls, and exposure can trigger allergies, lung inflammation, and asthma

asbestos

A long, thin, fibrous silicate mineral with insulating properties, which can cause cancer when inhaled

describe the dangers of asbestos

• respiratory diseases such as asbestosis and mesothelioma

• safe when undisturbed, but old or damaged materials release fine fibers → careful removal

radon-222

radioactive gas that occurs naturally from the decay of uranium and is an indoor air pollutant

where does radon enter from

• foundation cracks or contaminated groundwater

what does radon decay into and why is that bad

• decays into polonium-210, which can attach to dust and be inhaled, increasing the risk of lung cancer

health effects of radon 222 and 4 solutions

• second leading cause of lung cancer, and recommends testing, ventilation, mitigation systems, and sealing cracks to reduce indoor exposure

describe 5 sources and 3 effects of VOCs

• building materials, furniture, paint, glues, fabrics

• asthma irritation cancer

source and effect of lead

• from old lead-based paint, demolishing these buildings

• can come from outside soil or air, but ingestion of paint chips remains the greatest exposure risk for young children

sources of NOX and SOX

• can also accumulate indoor via poorly insulated or loosely sealed buildings

• NOX from indoor combustion sources like cooking

sources of indoor air pollution in developing countries

• burning wood, animal manure, or coal indoors for heat and cooking produces high concentrations of PM

• poor building insulation and ventilation may allow some pollutants to escape, but if outdoor air quality is also poor, ventilation provides only limited improvement

why is indoor air quality important in developed countries

• people spend more time indoors and buildings are more tightly sealed for energy efficiency, trapping pollutants inside

sources of indoor air pollution in developed countries

• widespread use of VOC materials, formaldehyde, plastics, and petroleum-based products leads to off-gassing of chemicals

sick building syndrome

• buildup of toxic pollutants in weatherized spaces, such as newer buildings in the developed world; ventilation is inadequate and contaminants accumulate, headaches, nausea, irritation