Air-pollution-control...pptx

Air Pollution Control

PURE AIR 78.1% N2 20.9% O2 0.9% Ar 0.04% CO2 0.002% Ne 0.0005% He

METEOROLOGY OF AIR POLLUTANTS

0.1% air

little mixing

80% air

well-mixed

4 Strata based on Temp Profile

METEOROLOGY OF AIR POLLUTANTS global wind patterns - differential warming and cooling of eart as it rotates (sun) local winds - differential temperatures between land and water masses ex: sea breeze -progressive warming of the land during a sunny day

METEOROLOGY OF AIR POLLUTANTS very stable

air stability measure of verticar air movement

unstable

• wind - horizontal movement + dispersion of air pollutants • adiabatic lapse rates - warming and cooling at 1 degC/100 m (dry air) • prevailing lapse rates - actual T-elevation measurements

METEOROLOGY OF AIR POLLUTANTS • superadiabatic lapse rate - characterized by great deal of vertical air movement and turbulence

METEOROLOGY OF AIR POLLUTANTS • subadiabatic lapse rate - dampen out vertical movement; limited vertical mixing

METEOROLOGY OF AIR POLLUTANTS • inversion - vertical movement is almost nil

night time

METEOROLOGY OF AIR POLLUTANTS • serious air pollutions accompanied by inversions fog “tiny droplets of water” -converts SO3 to H2SO4; screens the sunlight

METEOROLOGY OF AIR POLLUTANTS

• EXAMPLE

AIR POLLUTANTS CHARACTERIZATION • Particulates - includes dusts, fumes, mists, smoke, spray

AIR POLLUTANTS CHARACTERIZATION Dust  entrained by gases directly from material handled/procesed direct offspring of a parent material undergoing a mechanical operation entrained materials used in mechanical operation (sandblasting)

cement dust 100 µm

AIR POLLUTANTS CHARACTERIZATION • fume, 0.03 - 0.3 µm frequently metallic oxides formed by condensation of vapors by sublimation, distillation, calcination

AIR POLLUTANTS CHARACTERIZATION • mist, 0.5 - 0.3 µm entrained liquid particle formed by condensation of vapors or chemical reaction oil mist (metalworking process)

AIR POLLUTANTS CHARACTERIZATION • smoke, 0.05 - 1 µm entrained solid particles from incomplete combustion of carbonaceous materials

AIR POLLUTANTS CHARACTERIZATION • spray liquid particle formed from atomization of a parent liquid settle under gravity

AIR POLLUTANTS CHARACTERIZATION Measurement of Particulates

• Total suspended particulate (TSP) refers to the totality of small solid matter -primary contributor to air pollution

high-volume sampler (gravimetric)

AIR POLLUTANTS CHARACTERIZATION Example

AIR POLLUTANTS CHARACTERIZATION Respirable Particulates 50% enough particle mass assoc PM10- small to with 4-µ particles enter the thoracic region of human respiratory tract; smaller than 10µm PM2.5 - smaller than 2.5µm; so small and light they tend to stay longer in the air

PM10 sampler (centrifugal)

WHO exposure limits

AIR POLLUTANTS CHARACTERIZATION Gaseous pollutants

Unit: ppm (vol/vol),µg/m3

• Substances that are µg = MW x 100 x ppm gases at normal T&P 3 m 24.5 • Vapors that are L or S • CO, HC’s, H2S, NO, O3 + oxidants, SOx, CO2, CH4

AIR POLLUTANTS CHARACTERIZATION Example

Gaseous pollutants

AIR POLLUTANTS CHARACTERIZATION Gas Measurement Techniques • Wet chemistry method – use of a bubbler and wet chemical techniques

SO2 + H2O2 = H2SO4 then titration

Gaseous pollutants

AIR POLLUTANTS CHARACTERIZATION

Gas Measurement Techniques • Colorimetric (pararosaniline) method – measurement of absorbance

SO2 + TCM (tetrachloromercurate) = complex

Gaseous pollutants

AIR POLLUTANTS CHARACTERIZATION

Gas Measurement Techniques • Emerging techniques

Gaseous pollutants

AIR POLLUTANTS CHARACTERIZATION

Gas Measurement Techniques Emerging techniques  Non-Dispersive Infrared Photometry (NDIR) -preferential absorption of infrared radiation by a constituent, e.g., carbon monoxide (CO) -difference between the amounts of energy reaching the detector via the reference cell and that via the sample cell would be proportional to the CO concentration Chemiluminescence Technique -pollutant reacted with a specific reactant (in large excess) the product molecules formed would be at a higher state of excitation and subsequently release light (energy) -intensity of the emitted light would be directly proportional to the concentration of the pollutant

Gaseous pollutants

AIR POLLUTANTS CHARACTERIZATION

Gas Measurement Techniques Emerging techniques  Conductometric Technique -change in conductivity of the sample (when absorbed in a suitable liquid) would be proportional to the concentration of the pollutant  Coulometric Technique -reacting the gaseous sample with an KI or KBr solution in an electrolytic cell -current proportional to oxidants present Electrochemical Technique -consist of a semi-permeable membrane, an electrolyte film, a sensing electrode and a reference electrode immersed in the electrolyte; voltage difference

Gaseous pollutants

HOMEWORK#1 02/20/2019 • ENVIRONMENTAL REGULATIONS 1. The Philippine Clean Air Act of 1999 (RA8479) – salient features and agency mandates 2. DAO 2013-26 – AT LEAST 5 SENTENCES 3. IRR – REPUBLIC ACT NO. 8749 – AT LEAST 10 SENTENCES 4. MONTREAL PROTOCOL

CHARACTERIZATION OF AIR POLLUTION EMISSIONS QUIZ • True/False: The darker the smoke, the more pollution it brings.

CHARACTERIZATION OF AIR POLLUTION EMISSIONS Measurement of Smoke

CHARACTERIZATION OF AIR POLLUTION EMISSIONS Measurement of Smoke

• In-line capture - sample is sucked through a filter; gravimetric; for slight concentrations • Filter/dilution tunnel - smoke sample is drawn through a tube where it is diluted with air; gravimetric (international method) • Optical scattering – amount of light reflected by particle ~ concentration

CHARACTERIZATION OF AIR POLLUTION EMISSIONS Visibility – reduction in visibility is one of the obvious effects of air pollutants Loss of visibility – condition when it is just possible to identify a large object in bright daylight, or - Just possible to see a moderately bright light at night - Vague… but defines limits of visibility

CHARACTERIZATION OF AIR POLLUTION EMISSIONS Visibility Small particulates – with the most effective reduction in visibility Adsorbs light Scatters the light – reduces contrast between light and darker objects

CHARACTERIZATION OF AIR POLLUTION EMISSIONS Visibility Approximate expression for visibility: Limit of visibility

*Lv, km = 1.2 x 103 C, µg/m3 Particulate concentration

*for atmospheres <70% MC

SOURCES OF AIR POLLUTANTS 1. Natural sources - smoke particles from forest fires, HC’s from terpenes, H2S from amino acids break down

2. People-made sources Stationary combustion processes – oil and coal combustion

Transportation sources – smoke, CO, NOx, HC’s, smoke, Pb particles

Industrial process Solid waste disposal – backyard burning, incinerators, landfills

SOURCES OF AIR POLLUTANTS • HOMEWORK #2 1. Enumerate and discuss the 4 most difficult problems encountered relating air pollution to health.

SOURCES OF AIR POLLUTANTS • Air Pollution to Health correlation threshold - dose response curves mostly non-linear, some unknown total body burden - account for other intake sources (food, water); e.g., Pb time vs dosage - max allowable concentrations for a given time synergism - collective effect; e.g., black lung disease (coal mining + cigarette smoking)

SOURCES OF AIR POLLUTANTS • HOMEWORK

SOURCES OF AIR POLLUTANTS

0.1 µm Particulates  H2SO4 droplets  Pb particles

SOURCES OF AIR POLLUTANTS • SO2 -Irritant, restricts air flow, slows action of cilia Highly soluble mucous membrane (adsorption to tiny particles) Deep lung

SOURCES OF AIR POLLUTANTS

SOURCES OF AIR POLLUTANTS • SOx, NOx, Acid Rain fuels

High-T combustion

 Aquatic effect  Pollution across political boundaries (USA, Brit)

SOURCES OF AIR POLLUTANTS

• Photochemical smog Primary pollutants Secondary pollutants

Ozone, aldehydes, organic acids, epoxy compounds

SOURCES OF AIR POLLUTANTS Photochemical smog

SOURCES OF AIR POLLUTANTS • Ozone depletion ODS: CFCl3, CF2Cl2 (Montreal 1987)

Polar vortex

SOURCES OF AIR POLLUTANTS Global Warming

SOURCES OF AIR POLLUTANTS Global Warming

SOURCES OF AIR POLLUTANTS

Homework #3: Read and discuss Gaia hypothesis in at least 5 sentences.

SOURCES OF AIR POLLUTANTS

Indoor Air quality – a ventilation factor

SOURCES OF AIR POLLUTANTS

Indoor Air quality – a ventilation factor  Secondary smoke (high CO, particulates)  “Sleepy driver” syndrome  Radon – naturally emitted gas entering homes through basements, water, building materials (natural decay chain)

Po, Pb, Bi

Lung cancer

SOURCES OF AIR POLLUTANTS

Indoor Air quality – a ventilation factor

SOURCES OF AIR POLLUTANTS

Indoor Air quality – a ventilation factor

SOURCES OF AIR POLLUTANTS

Indoor Air quality – a ventilation factor

Reading Assignment • Homework#4: CONTROL OF AIR POLLUTANTS (Intro to Envi Engg, Vesilind, et.al p.455-475) • For 02/25-03/01/2019 • problems to follow