LECTURE 01 Cast of Characters AOSC 434 Air

LECTURE 01 Cast of Characters AOSC 434 Air Pollution Russell R. Dickerson www. atmos. umd. edu/~russ/syllabus 434. html

London killer smog

Donora, PA October 29, 1948; 2: 00 pm LST

1950’s local – 2000’s global.

Washington Post Jan. 25, 2014 “China’s air pollution prompts creative, sometimes wacky, solutions”

Air pollution, seen here over Mexico City, has many effects that are detrimental to the economy. Joshua Graff Zivin, and Matthew Neidell Science 2018; 359: 39 -40 Published by AAAS

Pollution and Smog Seinfeld & Pandis Ch. 2 Finlayson-Pitts & Pitts Ch. 1 Wark & Warner Ch. 1 Jacob Chapters 12 & 13.

Definitions • Los Angeles Smog (photochemical smog) is the mixture of ozone, hydrocarbons, partially oxidized hydrocarbons, oxides of nitrogen and other trace gases that results from the action of sunlight on automobile exhaust and other pollutants. It is characterized by high temperatures stagnant winds (high barometric pressure), and sunny conditions. • London Smog (particulate, or sulfurous smog) is a mixture of sulfur dioxide and sulfate and sulfite aerosol resulting primarily from the combustion of high sulfur coal followed by conversion of SO 2 to H 2 SO 4. It is characterized by low temperatures, high humidity and stagnant winds.

Air Pollutants Photochemical and London Smog Species Involved Including Criteria Pollutants Limit here refers to the National Ambient Air Quality Standard (NAAQS) established by the US-EPA.

1. Ozone, O 3 (Photochemical Oxidant) criteria pollutant Secondary • Effects: 1. Respiration - premature aging of lungs (Bascom et al. , 1996); mortality (e. g. , Jerrett et al. , 2009). 4%/10 ppb. 300, 000 deaths/yr (Landrigan et al. 2017) 2. Phytotoxin, i. e. Vegetation damage (Heck et al. , JAPCA. , 1982; Schmalwieser et al. 2003; Mac. Kinzie and El-Ashry, 1988) 3. Materials damage - rubber 4. Greenhouse effect (9. 6 m) • Limit: (National Ambient Air Quality Standard) 80 ppb for 1 hr. 1971 120 ppb for 1 hr. 1979 84 ppb for 8 hr 1997 75 ppb for 8 hr 2010 70 ppb for 8 hr 2015 • Ozone is an indicator of smog. • Ozone regulates many other oxidants

Ozone damaged plants.

What does history tell us? • Denora, Pitt, and London were sulfurous smogs. • Early work in Los Angeles focused on SO 2 from refineries – smog got worse. • VOC’s targeted next – smog got worse. • Denora, London, etc. were worse in winter – LA was worse in summer. • Burning eyes in LA. 18

What does history tell us? P. L. Mc. Gill, Stanford Research Institute*, “The Los Angeles Smog Problem” Industrial and Engineering Chemistry, 2476 -86, 1949. “Unquestionably the most disagreeable aspect of smog is eye irritation. ” They blamed elemental sulfur. Mechanism of the Smog: “Weather conditions control the time of occurrence of eye-irritating smog in Los Angeles. ” Meteorology and topography. Identified temperature inversions and stagnant winds as contributors. No mention of combustion, ozone, photochemistry, or automobiles other than as a source of H 2 CO that did not cause eye irritation. *supported by The Western Oil and Gas Association. 19

Haagen-Smit (1952) “Photochemical action of nitrogen oxides oxidized the hydrocarbons and thereby forms ozone…. ” Almost right. 20

Ozone is a national problem

2. Nitrogen Dioxide, NO 2 criteria pollutant Primary Effects: 1. Lungs (acute chemical pneumonia) EPA Criteria Pollutant 2. Phytotoxin 3. Catalyst for ozone formation. 4. Atmospheric acidity (about 1/3 of problem and growing) Limit: 100 g m-3 (53 ppb) annual mean 200 g m-3 (100 ppb) hourly mean (2010)

3. Carbon Monoxide, CO criteria pollutant Primary Effects: 1. Respiration (acute); EPA Criteria Pollutant 2. Cardiovascular system (chronic) 3. Contributor to photochemical smog 4. Changes global HOx cycle (oxidizing capacity of atmosphere). Limits: 9. 0 ppm for 8 hr 35 ppm for 1 hr 50 ppm for 8 hr is the "level of significant harm"

3. Carbon Monoxide, CO (cont…) • • Affinity for hemoglobin 200 times that of O 2. Displaces O 2 at [CO] = 0. 2 x 106/ 200 = 103 ppm. Concentrations above 750 ppm are fatal. Concentrations > 100 ppm cause dizziness, headache, loss of visual & mental acuity. • Cigarette smoke contains ca. 400 ppm CO (also HCN, H 2 CO, Ni(CO)4, NO 2).

4. Peroxyacetyl Nitrate, "PAN" (CH 3 C(O)-O-O- NO 2) not a criteria pollutant Secondary Effects: 1. Eye irritation 2. Respiratory tract (carcinogen? ) 3. Phytotoxin Limits: None (too hard to measure) • Compound "X" in LA smog • NOx reservoir.

An interesting history Smogtown, by Jacobs and Kelly, Overlook Press, 2008. 29

5. Polynuclear Aromatic Hydrocarbons, "PAH" (Also Polycyclic Aromatic Hydrocarbons) See Also Finlayson-Pitts Chapt. 9&10. Primary Effects: 1. Carcinogenic (one of the few known carcinogens in air) Limits: None • Low/moderate vapor pressure; divided between particulate & gas-phases. • Example: Benzo(a)pyrene (Ba. P) • Nitrated PAH even stronger carcinogens.

6. Ethylene, H 2 C=CH 2 Primary Effects: 1. Ozone formation 2. Plant hormone (e. g. oranges) Limits: None • Other biogenic hydrocarbons, isoprene, pinenes. • Some plants when stressed release more ethylene

7. Formaldehyde, H 2 CO Primary and secondary Effects: 1. Ozone formation 2. Eye irritant 3. Mutagen, suspected carcinogen Limits: None • Indoor air pollutant too, (ureaformaldehyde insulation) • Produced by HC oxidation • Represents class of partially oxidized HC

8. Lead, Pb criteria pollutant Primary Effects: 1. Toxic, leads to loss of mental acuity. Limits: 0. 15 µg/m 3 rolling three month average. Now primarily a problem of the developing world.

9. Other Pollutants (toxics) Halogenated Hydrocarbons Example: Dioxin Effects: 1. Teratogen 2. LD 50 in guinea pigs is 0. 5 to 1. 0 g/kg Limits: None • Produced as byproduct in 2, 4 -D and 2, 4, 5 -T synthesis and by incomplete combustion of chlorine containing refuse such as plastics. • "Freons" will be considered as part of stratospheric air pollution.

LONDON-TYPE SMOG 10. Sulfur Dioxide, SO 2 Primary Effects 1. Produces H 2 SO 4 found on particles and in precipitation - Acid Deposition 2. Cloud Condensation Nuclei (climate) 3. Materials degradation 4. Respiratory tract (esp. bisulfites, HSO 3 -) 5. Phytotoxin

10. Sulfur Dioxide, SO 2 (cont…) Limits: Primary 1 -hr Standard: 75 ppb (June 2010) Secondary standard 500 ppb for 3 hr SO 2 (HSO 3 -)aq H 2 SO 4 (+ NH 3) NH 4 HSO 4 (+ NH 3) (NH 4)2 SO 4 • EPA Criteria Pollutant • No catalytic photochemistry • More on chemistry and physics later

11. Fine Particulate Matter (PM 2. 5) Aerodynamic Diameter < 2. 5 μm Limits: 35 μg m-3 for 24 hr 12 μg m-3 annual mean (150 μg m-3 for 24 hr for PM 10) • Primary and secondary pollutants. • Major health effects: • More on chemistry and physics later

Wet deposition of sulfate

12. Carbon Dioxide, CO 2 Primary Non toxic below percent levels. Dominant greenhouse gas.

Health Effects 3 Steps for Estimating • Epi Study determines C-R function • Estimate incidences and change in exposure • Calculate deaths and assign a value

Local, Regional, Global Pollution Before 1950 s: Local Smoke, Fly ash 1970 s-1990 s: Regional Acid Rain, Haze Post- 2000 s: Global Change

Deaths per year, worldwide From Lancet 2017.

Lecture Summary There a vast variety of pollutants, and the problem has changed from local to global. They have health, environmental, climate, and/or welfare effects. You will be expected to know the name and basic facts of each pollutant or pollutant family. This course will provide you with the tools to understand the impact, sources, chemistry, transport, meteorology, trends, and sinks for all of these pollutants – and some that have not been discovered yet.

TROPOSPHERIC Ozone Photochemistry CLEAN AIR (1) O 3 + h O 2 + O(1 D) (2) O(1 D) + H 2 O 2 OH (3) OH + O 3 HO 2 + O 2 (4) HO 2 + O 3 2 O 2 + OH -------------------- (3+4) 2 O 3 3 O 2 NET

DIRTY AIR (3') OH + CO 2 (4') H + O 2 + M HO 2 + M (5') HO 2 + NO NO 2 + OH (6') NO 2 + h NO + O (7') O + O 2 + M O 3 + M ------------------------ (3'-7') CO + 2 O 2 CO 2 + O 3 NET

Similar Reaction Sequence For Methane CH 4 + OH CH 3 + H 2 O CH 3 + O 2 + M CH 3 O 2 + NO NO 2 + CH 3 O + O 2 H 2 CO + HO 2 + NO NO 2 + OH NO 2 + h NO + O 2 + M O 3 + M -----------------------------------CH 4 + 4 O 2 + h 2 O 3 + H 2 CO + H 2 O NET

What Is The Fate Of Formaldehyde? 2 H 2 CO + h H 2 + CO HCO + H H + O 2 + M HCO + O 2 HO 2 + CO ----------------------2 H 2 CO + 2 O 2 2 CO + 2 HO 2 + H 2

This means two ozone molecules are produced per formaldehyde. The grand total for methane is four O 3 produced! Methane is a good model for all alkanes, but by itself reacts too slowly to form much ozone locally, it is, however, important on a global scale. The net production of ozone requires converting of NO to NO 2 without consuming O 2.

International Journal of Chronic Obstructive Pulmonary Disease, 2014

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