Chapter 19: Air Pollution and Noise Living and Working in a Healthy Environment

Sources of air pollution Image from www.collegesherbrooke.qc.ca/~graphycs/martinaube.html

Sources of air pollution Emissions Anthropogenic (manmade): Fossil fuel combustion, biomass burning, industrial processes, etc. Biogenic: Emissions from vegetation, soil, wildlife, forest fires, etc. Other natural: Volcanos, lightning, sea salt, meteors, windblown dust, etc. Photochemical production from other compounds in atmosphere (“secondary source”) Transport: If considering only troposphere, then transport from stratosphere is a source

Primary & secondary pollutants CO2, etc. CO, VOC HO2 OH NO NO2 O3 Secondary VOC NOx O3 Primary (e.g., lead) Primary: Emitted directly to the atmosphere Secondary: Forms in the atmosphere

Sources of the 5 major pollutants in the U Sources of the 5 major pollutants in the U.S Note: Historically, the 6th Major Pollutant was lead.

Source and Composition of Particulates meteoritic material soot sulfates, ash Soot, sulfates, VOCs soot sea salt Soot, organic Soot, NOx, VOCs methane, ammonia Minerals, clays

Emission events (Nov. 18, 2008) Textruve Plant on 2001 Sheldon Road (Channelview, TX) Picture taken at 6:00 pm on site Picture taken at 4:00 pm from 20 miles away

Impacts: Ozone and PM2.5 Non-Attainment U.S. EPA, 2006 Source: U.S. EPA

Fine PM levels in Clinton Drive (Houston, TX) Very close to non-attainment

Primary standard: Necessary to protect the public health Texas Air Quality Let’s consider those compounds that the Federal Government regulates  National Ambient Air Quality Standards (NAAQS) Secondary standard: Necessary to protect the public welfare and the environment The Clean Air Act requires these standards to be set at levels that protect public health with an adequate margin of safety and without consideration of cost. Primary standard: Necessary to protect the public health 10 The light gray standards have been recently added.

Lecture 32 Texas Air Quality http://www.airnow.gov/index.cfm?action=airnow.national

U.S. Federal Regulation of Air Pollution Air pollution Control Act of 1955 Clean Air Act of 1963 Amendment to CAA - Motor Vehicle Air pollution Control Act of 1965 1970 Clean Air Amendments and formation of the EPA. 1975 catalytic converter developed.

Signs that regulation works! U.S. pollution trends since 1977

Stratospheric ozone—The good ozone

Types of SMOG 1.Industrial London Smog – combination of smoke and fog At the end of the 1800’s, 40% less sunlight in London than surrounding towns Health effects Vitamin D deficiency, Rickets, Tubercolosis

2. Photochemical Smog Consists mainly of secondary pollutants: Ozone (O3), NO2, VOCs Forms when sunlight induces chemical changes in gases and aerosols Causes poor visibility, burning eyes, sore lungs, worsen conditions of the heart and lungs, possible mortality.

Photochemical and Industrial Smog “London Smog or Industrial Smog” Gray-air in New York City “LA Smog”: Brown-air smog in Los Angeles © Dean D. Fetterolf/ShutterStock, Inc. © Chad Littlejohn/ShutterStock, Inc.

Houston Case Which kind of smog do you think Houston has? Why is Houston different from London or LA case? How much do you think pollution from Houston will influence College Station?

Ozone (O3) in the Troposphere Photochemical Smog Ozone (O3) in the Troposphere Most problematic air pollutant in many areas of the U.S. Ozone is not directly emitted into the atmosphere, but instead forms through a complex series of reactions. It is largely because of this complexity that ozone is so difficult to control. I usually apologize for the excessive chemistry here, but explain that it’s impossible to discuss tropospheric ozone without it. Explain that hn simply indicates that a photon is absorbed by the molecule, which leads to decomposition (i.e., photolysis). The n is just frequency.

Ozone chemistry (gas-phase only) NO3 N2O5 hn O3 NO2 NO HNO3 HONO HO2 RO2 H2O hn H2O2 VOC This represents a simplistic overview of the gas phase reactions involved in ozone production. I highlight NOx and VOCs since these are the precursors that we can control.

The next two slides are meant to accompany a discussion of how emissions rates are measured. Measuring what comes out of a stack is pretty straightforward. Measuring the thousands of small leaks in a massive refinery such as those in Houston is more challenging. During TexAQS2000 aircraft measurements indicated that VOC emissions from many of the refineries in Houston far exceeded the reported values.

What’s a dynamometer? Measuring auto and truck emissions is usually accomplished by either putting the vehicle on a dynamometer and sampling the exhaust, or by sampling pollutant levels in tunnels. The Caldicott tunnel shown above (near San Francisco) has been used extensively for the latter type of study since it has two bores, one of which is used only by cars. This permits separation of the auto emissions from those from diesel trucks Measuring auto and truck emissions is usually accomplished by either putting the vehicle on a dynamometer and sampling the exhaust, or by sampling pollutant levels in tunnels. The Caldicott tunnel shown above (near San Francisco) has been used extensively for the latter type of study since it has two bores, one of which is used only by cars. This permits separation of the auto emissions from those from diesel trucks.

NOx and VOC sources in the Greater Houston Area The take-home message from these figures is that NOx is emitted almost entirely as a result of combustion, whereas VOC emissions are often dominated by other sources such as trees, especially in the HOUSTON AREA…. The refineries and chemical plants in Houston are important sources of a range of VOCs. The take-home message from these figures is that NOx is emitted almost entirely as a result of combustion, whereas VOC emissions are often dominated by other sources such as trees. The refineries and chemical plants in Houston are important sources of a range of VOCs.

This is called an ozone isopleth diagram, and shows the ozone concentration that will result from different NOx / VOC mixtures. The plot on the previous slide essentially represents a vertical line here.

What is a unique hour.(just one hour at a time?) What is AQMD ?? I think H-G-B is Houston Galveston Beaumont Explain how sunlight drives photochemistry and causes high OZONE This shows the number of exceedances in Houston over the past 9 years. Most high ozone days occur in the summer when there is plenty of sunlight to drive the photochemistry, warm temperatures accelerate some of the reactions, and temperature inversions often limit vertical mixing. After taking the lead in 1999 and 2000, Houston has dropped back below Los Angeles in the number of annual exceedences. The annual variability is caused primarily by meteorology. This shows the number of exceedances in Houston over the past 9 years. Most high ozone days occur in the summer when there is plenty of sunlight to drive the photochemistry, warm temperatures accelerate some of the reactions, and temperature inversions often limit vertical mixing. After taking the lead in 1999 and 2000, Houston has dropped back below Los Angeles in the number of annual exceedences. The annual variability is caused primarily by meteorology.

Ozone Non-attainment: Old standard

Ozone Non-attainment: New standard

19.2 The Effects of Climate and Topography on Air Pollution Air pollution levels in a region are affected by a number of factors, among them: Temperature Sunlight Wind Other climate factors They are also affected by the topography.

FIGURE 05a: Temperature profiles: normal pattern

FIGURE 05b: Temperature profiles: temperature inversion

The Health Effects of Air Pollution FIGURE 6: Urban air pollution and incidence of emphysema in Winnipeg and St. Louis Air pollution: adversely affects human health damages the environment and the organisms that live in it damages buildings and a wide assortment of materials, costing billions of dollars a year Air pollution causes many immediate effects, such as: shortness of breath eye irritation upper respiratory tract irritation Few people are aware of the source of these problems. In extreme cases, pollutants can become lethal Long-term exposure to air pollution may result in a number of diseases, including: Bronchitis Emphysema Asthma Lung cancer Three groups are generally the most susceptible to air pollution: The young The old The infirm (sick)

Effects on Plants and Nonhuman Animals FIGURE 7: Trees killed by acid deposition in Pisgah Nation Forest, North Carolina © Jerry Whaley/age fotostock

Power Plant NOx Control: Staged Combustion Low-NOx Burners: Precisely control combustion to reduce NOx Natural gas reburn: Creates fuel-rich zone and radicals which destroy NOx Over-fire air: Completes the combustion Together, can reduce NOx by ~50-75% US DOE NETL

Power Plant Sulfur Dioxide Control Initially dispersed by tall chimneys “Solution to pollution is dilution” Low sulfur coal Some coals (e.g., Western U.S.) contain less sulfur Flue Gas Desulfurization Sorbent such as limestone or lime is injected to remove 80-98% of SO2 Cobenefit of reducing mercury emissions Byproduct can be used in wallboard, cement 3-7% energy penalty Parish Power Plant Unit 8 FGD System

Power Plant NOx Control: Selective Catalytic Reduction (SCR) Ammonia is injected after boiler to convert NOx to N2 and water Requires catalyst Specific temperature range ~85% NOx reduction www.de-nox.com

Automobile Emission Controls 3-way catalytic converter Reduces NOx, oxidizes CO and hydrocarbons Oxygen sensor: Controls air-fuel ratio Diesel particulate filters and oxidation catalysts Cleaner burning fuels Unleaded gasoline: No lead emissions; preserves catalyst Low sulfur fuels: Preserves catalyst Added oxygenates: Reduce CO

Catalytic Converters A. Reduction Catalyst: B. Oxidation Catalyst: 2NO  N2 + O2 B. Oxidation Catalyst: 2CO + O2  2CO2 CxHy + (x+y/4)O2  xCO2 + (y/2)H2O CO2 is dominant component of exhaust, not significantly affected by controls 19.4 lb CO2/gal gasoline; 22.2 lb/gal diesel 37

Diesel Particulate Filter Volkswagen

Electrostatic Precipitator (ESP) Suspended particles are charged by electron field Particles travel to collection plate Plates are rapped to make PM fall to hoppers ~99% efficiency ceenve3.civeng.calpoly.edu/cota/ENVE411-ESP.html

19.5 Noise: The Forgotten Pollutant Sound is characterized by loudness (measured in decibels) and pitch (how high or low it is).

How Loud is Too Loud? www.warrencenter.org/howloud.html Prolonged exposure to any noise above 85 decibels (dB) can cause gradual hearing loss. At higher decibel levels, hearing protection is strongly recommended. 100 decibels - no more than 15 minutes prolonged exposure recommended 110 decibels - regular exposure of more than one minute risks permanent hearing loss without hearing protection. www.warrencenter.org/howloud.html

FIGURE 14: Radon protection Indoor Air Pollution FIGURE 14: Radon protection