Air Quality Teri L. Conner, Ph.D. Whats your AQ IQ? Some infamous air pollution episodes 2 20 excess deaths 6000 made ill New York City Thanksgiving Day excess deaths London December 1952 >3000 excess deaths Whats common to each episode? Particles Sulfur dioxide (SO 2 ) Some really unfortunate meteorology 3 Problems not limited to air 4 Rail car accident set the oily Cuyahoga River on fire in 1969 Photo Credit: Cleveland State University Special Collections The First Earth Day Wisconsin Senator Gaylord Nelson got it started Called for demonstration on behalf of the environment Spring 1970 nationwide - grassroots Everyone was invited .and EVERYONE CAME! 5 AP Photo The Environmental Protection Agency In 1970, Congress passed the Clean Air Act, giving the federal government legal authority to develop regulations to limit air emissions The EPA was created on May 2, 1971 to implement the various requirements included in the Clean Air Act 6 Clean Air Act 1970: So what did it do? National Ambient Air Quality Standards (NAAQS) Sets limits on certain air pollutants State Implementation Plans (SIPS) Tells how each state will control air pollution New Source Performance Standards (NSPS) standards for new and modified stationary sources National Emission Standards for Hazardous Air Pollutants (NESHAPS) Regulate specific types of toxic air pollutants Control of motor vehicle emissions Regulate fuels, emission control 7 Air Pollutants Can be gases, liquids (aerosol droplets), or solids (particles) Thousands of pollutants not practical to regulate all Choose some that are found everywhere and harm health and environment What was common to those infamous air pollution episodes? EPA chose six criteria pollutants to regulate: Particulate Matter (PM) Ozone (O 3 ) ground-level Carbon monoxide (CO) Sulfur dioxide (SO 2 ) Nitrogen dioxide (NO 2 ) Lead (Pb) Many other hazardous pollutants (Hg, PCBs, pesticides..) 8 Has it worked? 9 What about PM and Ozone? 10 What is Particulate Matter? Complex mixture of solid and liquid particles (yes, liquid), also called aerosols Vary in number, SIZE, shape, surface area, chemical composition, solubility, reactivity and origin 11 What about particle size? Size distribution is TRIMODAL Coarse, Fine, and Ultra-fine different origin, transport, composition, removal 12 What sizes are regulated? This has changed over the years Started with Total Suspended Particulate (TSP) Changed to PM10 inhalable size fraction Added PM2.5 respirable linked to serious health problems Currently still have PM10 and PM2.5 13 More About Particle Size Coarse Particles - PM2.5-PM10 Particles bigger than 2.5 m but smaller than 10 m Inhalable Mainly from resuspension of dust, soil, crustal materials from roads, construction, farming, mining, wind, volcanoes Fine Particles - PM2.5 Particles smaller than 2.5 m Respirable Linked to serious health problems Primary (direct) emissions - combustion from motor vehicles, power generation, industrial processes Secondary (indirect) emissions - formed by reactions of gases (e.g.,SO 2 from coal burning; NO 2 from autos) PM10 includes FINE and COARSE 14 How big is PM2.5, PM10? 15 Human Hair (70 m diameter) Hair cross section (70 m) PM 2.5 (2.5m) PM 10 ( 10m ) Particle size is based on diameter But how do we measure diameter of something small, irregular, and 3-dimensional? We cant use a tiny ruler! Use an effective diameter 16 Based on particle behavior Aerodynamic diameter is commonly used: Particle being measured falls at the same rate as a spherical particle with density equal to 1 (unit) We use air samplers that separate fine and coarse particles based on this concept Particulate Matter Air Samplers 17 Measure mass Measure composition Samples collected on filters Separate fine and coarse Particle Analysis X-ray fluorescence 18 This is an X-ray spectrometer Measures elemental composition Elements from Na to U I have used one of these photo courtesy of PANalytical How XRF Works 19 An x-ray of sufficient energy strikes an atom in the sample, dislodging an electron from one of the atom's inner orbital shells. The atom regains stability, filling the vacancy left in the inner orbital shell with an electron from one of the atom's higher energy orbital shells. The energy difference between the electrons initial and final orbital shells is released as an x-ray. These x-ray energies are element-specific. More Particle Analysis Scanning Electron Microscopy 20 This is a scanning electron microscope Get images and composition of individual particles Ive used one of these too An optical microscope uses visible light and a glass lens to make small objects look big Optical Microscope Scanning Electron Microscope A scanning electron microscope uses electrons (instead of light) and a magnet lens to make small objects look big More magnification than an optical microscope Can also measure elemental composition Common SEM Applications Measure size and shape of particles Salt from marine ai r Baltimore air particles DiatomPollen Fibers and particles from World Trade Center Dust Salt ParticleIron Particle (Steel Plant) Common SEM Applications Determine what the particle is made of Spherical iron particle from steel processing Fly ash from coal combustion Soot from diesel vehiclesMalaysian Forest Fire Emissions Common SEM Applications Figure out where particles come from outdoor air Fine House DustCigarette smoke indoors Common SEM Applications Figure out where particles come from indoor air Whats in your personal cloud? AntiperspirantCotton Shirt Fibers Eye Shadow Air Freshener Questions? (or shall I talk more..)