BIG DUE DATES! IA “RAC” Due: JANUARY 19th (FRIDAY) QUIZ: JANUARY 25th (THURSDAY) Acid Deposition A.S: N – R Ozone Depletion A.S: S – W Last Chance to See Due 3rd marking pd Chapter Summaries & Favorite Quote Come sign out a book!!

Urban Air Pollution & Monitoring Topic 5: Atmosphere A.S. : X – CC

What is Air Pollution? Air pollution is the introduction of many kinds of gases, chemicals, particulate matter or biological materials into the atmosphere by humans

Causes The combustion of fossil fuels produces primary pollutants such as: Carbon monoxide Carbon dioxide Black carbon (soot) Unburned hydrocarbons from the incomplete combustion of engine exhaust or VOCs (Volatile Organic Compounds) NOx SOx

Photochemical Smog In the presence of sunlight, secondary pollutants are formed when the primary pollutants undergo reactions with other chemicals already present in the atmosphere. Photochemical Smog is a mixture of about 100 primary and secondary pollutants formed under the influence of sunlight. Tropospheric Ozone is the main pollutant!

Sources of Tropospheric Ozone                                                                                                                                                                       EPA Graphic

Formation of Tropospheric Ozone Tropospheric Ozone = “Bad Ozone” Burning of fossil fuels emitted by automobiles, gasoline vapors, and power plants creates NO (nitric oxide), The NO reacts with Oxygen (is oxidized) to form NO2 (nitrogen dioxide) a brown gas that contributes to urban haze. NO2 gets hit with a UV ray, breaking off a free oxygen atom. This combines with an oxygen molecule (O2) to form Tropospheric Ozone (O3). - When will ozone levels reach their peak in an urban environment? - Is T. Ozone a primary or secondary pollutant? SECONDARY!

Thermal Inversions The levels of photochemical smog can vary by: population density, fossil fuel usage, climate, and topography. Under normal conditions air rises and disperses pollutants. A thermal inversion, occurs where a layer of warm air sits over a layer of cooler air, which prevents the dispersal of the pollutants. The trapped dense, cooler air becomes stagnant and accumulates more and more pollutants. Occurs in cities located in valleys surrounded by mountains, with light winds and lots of people driving cars! Ex. Los Angeles, Mexico City, Beijing What will get rid of the pollutants?

Thermal Inversion

LOS ANGELES, MEXICO CITY, RIO DE JANEIRO, BEIJING, AND EVEN DENVER, CO & SEATTLE, WA London’s Great Smog of ’52

Los Angeles Overtime A is from 1940’s B is from 1960’s C is from 1990’s

Face Masks in Beijing

Photo taken by Bobak Ha'Eri                                                                                                                                                                  Beijing, China air on a day after rain (left) and a sunny but smoggy day (right) August 2005. Photo taken by Bobak Ha'Eri Sunday 11/8/15 CNN Report

Tropospheric Ozone Effects Respiratory irritation bronchial constriction asthma coughing/wheezing Eye irritation Decreases crop yields slows plant growth Damages plastics, rubber and nylon Has a harsh odor

Photochemical Smog

Direct method of monitoring air pollution Schoenbein Paper = ozone - using a mixture of starch, potassium iodide, and water spread on filter paper - The paper will vary in color depending on the amount of the oxidation. - Those that have a lavender appearance were exposed to more ozone, and those that look dark purple had high ozone exposures. - This is a qualitative test for comparison purposes - Relative humidity can affect results Evaluate this method:

Management Strategies for Urban Air Pollution Alter Human Activities – Regulate – The U.S. Congress passed Clean Air Acts in 1970, 1977, and 1990. Brought on by smog deaths in PA National Ambient Air Quality Standards (NAAQS) were established for six outdoor “criteria” (main) pollutants. Two limits were established: a primary standard is set to protect human health and a secondary standard is set to prevent environmental, property and crop damage. Restore – Alter: alternative energies, energy-efficient technologies, use public transportation, walking, biking………….Use of Catalytic converters Regulations: government taxation, emissions tests on cars, government fuel efficiency standards/regulations Restore: Waiting for rain, reforestation/regreening to sequester carbon dioxide.