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air Pollution sampling
- 1. AIR POLLUION sampling Presented by:Haseen Shoukat Atif Roll No: 14 28 16
- 2. POLLUTION Pollution, contaminationof the environment by man-made substances or energy that have adverse effects on living or non-living matter. This contamination of air, water, or soil materials interferes with human health, the quality of life, or the natural functioning of ecosystems. In simple terms, pollution can be seen as the wrong substance in the wrong place in the wrong quantities at the wrong time.
- 3. Air pollutants • Humanactivities that are major sources of outdoor air pollution, include: • Fuel combustion from motor vehicles (e.g. cars and heavy-duty vehicles) • Heat and power generation (e.g. oil and coal power plants and boilers) • Industrial facilities (e.g. manufacturing factories, mines, and oil refineries) • Municipal and agricultural waste sites and waste incineration/burning • Residential cooking, heating, and lighting with polluting fuels
- 4. Types of pollutants •Particulate matter (PM) Particulates can be further subdivided into five types: Aerosols Dusts Fumes Smokes Mists • Black carbon • Ground-level ozone • Nitrogen dioxide • Sulfur dioxide ( SO2) • Carbon monoxide (CO)
- 5. Sampling Air sampling: Capturingthe contaminant from a known volume of air, measuring the amount of contaminant captured, and expressing it as a concentration Air pollution sampling : Related to analysis of pollutants in a given volume of air.
- 6. AIR SAMPLING METHODS Airpollutant sampling are of two types :- Air sampling based on the particulate pollutant Air sampling based on the gaseous and vapor pollutant Air sampling techniques for particulate pollutants SEDIMENTATION FILTRATION IMPINGEMENT PRECIPITATION • THERMAL PRECIPITAION
- 7. • A liquidis added to collector to prevent the solids blown out from the Jar by air • Sampling period is 30 days • Collected dust is evaporated to dryness and then weighed in mg
- 9. are glass bubbletubes designed for the collection of airborne particles into a liquid medium Impinger
- 13. • Gaseous pollutantsare adsorbed on the solid surface of activated carbon, silica gel, activated alumina and molecular sieve • As the surface area increases the adsorption increase
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- 17. Spectrophotometry Spectrophotometry is basedon the absorption of radiation by gases at different wavelengths. When a light with a known intensity spectrum passes the sample, the exiting radiation’s intensity spectrum can be used to determine the composition of the gas. Spectrophotometry consists of two main parts: infrared spectrophotometry at wavelengths larger than 800nm, which relies on molecular rotation and vibration excitement; and ultraviolet-visible spectrophotometry in the wavelength range of 200–800 nm that is based on electron excitement and atomic absorption. Infrared spectrophotometry is primarily used for emission measurements of most pollutant gases, like CO, CO2, NO, SO2 and hydrocarbons. It is also widely used for CO and CO2 measurement for ambient and indoor air quality investigations Ultraviolet spectrophotometry is applied for the investigation of gases that have a significant absorption in the UV range, mostly NO and O3.
- 18. UV fluorescence • UVfluorescence is similar to UV spectrophotometry in a way that ultraviolet radiation is emitted into the sample. • UV fluorescence is mostly used for SO2-measurements, which absorbs 215 nm UV radiation and then emits fluorescent radiation between 240–420 nm with a peak of 320 nm.
- 19. Chemiluminescence • Chemiluminescence isthe most common way to measure the photochemical NO, NO2 and NOx concentrations. The method is based on the fact that during the reaction of NO with ozone, the resulting NO2 molecule is excited and releases radiation at 1100 nm wavelength • The measurement is carried out in two steps: at the beginning, the sample is split and the first part passes through a converter which reduces all NO2 to NO. • Then it gets into the measurement chamber where ozone is added at a constant rate. • due to cost and safety reasons, UV-spectrophotometry is more widely used for ozone concentration measurement
- 20. Gas chromatography • Gaschromatography is a measurement technique for most greenhouse gases like CO2, CH4, SF6 and N2O as well as for CO.
Editor's Notes
- #3 any contamination of the atmosphere that disturbs the natural composition and chemistry of the air. measurement of concentration of air pollutants, advantages of measurement of air pollutants, toxic gaseous pollutants, sulfur dioxide as a pollutant, nitrogen dioxide, carbon monoxide, methane (greenhouse gas) suspended matter and photochemical smog, analysis of suspended matter, analysis of photochemical smog, determination of other pollutants
- #5 Particulate matter (PM) are inhalable and respirable particles composed of sulphate, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water. Particles with a diameter of less than 10 microns (PM10), including fine particles less than 2.5 microns (PM2.5) pose the greatest risks to health, as they are capable of penetrating peoples’ lungs and entering their bloodstream. Sources of PM include combustion engines (both diesel and petrol), solid-fuel (coal, lignite, heavy oil and biomass) combustion for energy production in households and industry, as well as other industrial activities (building, mining, manufacture of cement, ceramic and bricks, and smelting). Black carbon is a major component of PM2.5 and driver of climate change, also known as a “short-lived climate pollutant." SLCPs persist in the atmosphere for a shorter period compared to CO2. Despite its short atmospheric lifetime, black carbon is one of the largest contributors to global warming after CO2. It also known to decrease agricultural yields and accelerate glacier melting. Ground-level ozone is one of the major components of photochemical smog and a key health risk linked to breathing problems, asthma, reduced lung function and respiratory diseases. It is a secondary pollutant, meaning that it is not directly emitted. Instead, it is produced when carbon monoxide (CO), methane, or other volatile organic compounds (VOCs) are oxidized in the presence of nitrogen oxides (NOx) and sunlight. In addition to their role as ozone precursors, CO, VOCs and NOx are dangerous air pollutants themselves. Major sources of NOx and VOCs include emissions from motor vehicle exhaust, industrial facilities, and chemical solvents. Major sources of methane include waste and the fossil fuel and agricultural industry. Aside from its health impacts, tropospheric ozone is a short-lived climate pollutant and one of the most important greenhouse gases. Nitrogen dioxide mainly emitted by power generation, industrial and traffic sources, is an important constituent of particulate matter and ozone. There is growing evidence that independently, it can increase symptoms of bronchitis and asthma, as well as lead to respiratory infections and reduced lung function and growth. Evidence also suggests that NO2 may be responsible for a large disease burden, with exposure linked to premature mortality and morbidity from cardiovascular and respiratory diseases. Sulfur dioxide ( SO2) is primarily produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores that contain Sulphur. Exposure to SO2 affects the respiratory system and the function of the lungs, and causes irritation of the eyes. Inflammation of the respiratory tract from SO2 can aggravate asthma and chronic bronchitis, as well as increases the risk of infection, leading to increased hospital admissions and visits to emergency rooms. SO2 also combines with water in the air to form sulfuric acid - the main component of acid rain. Carbon monoxide (CO) a colorless and odorless gas, which at high levels can be harmful to humans by impairing the amount of oxygen transported in the bloodstream to critical organs. Although high concentrations of CO are more of a concern indoors, emissions outdoors, particularly in developing countries can be high. New evidence also reveals that long-term exposure to low concentrations is also associated with a wide range of health effects. The main sources of ambient CO include motor vehicle exhaust and machinery that burn fossil fuels. Aerosol : Dispersion of solid particles of microscopic size in air. Dust: Solid particulate capable of temporary suspension in air. Fume: Solid particles produced by condensation from the gaseous phase. Fumes are usually derived from the heating of a solid to its melting point and the subsequent cooling of the gas produced. Smoke: Particles resulting from the incomplete combustion of organic matter consisting predominantly of carbon and oxides of carbon. Mist: Dispersion in air of liquid droplets usually large enough to be seen by the naked eye. Vapour: Gaseous phase of a substance that usually exists as a liquid or solid at normal room temperature and pressure. Gas: A substance which does not normally exist as a liquid or solid at normal room temperature and pressure.
- #6 The air is passed through a filter medium (normally a paper for solid & liquid contaminants and a sorbent for gases). The volume of air is measured against the amount of contaminant captured. This gives the concentration, which is expressed either as milligrams per cubic metre (mg/m3 ) or parts per million (ppm). The volume of air is calculated by multiplying the flow rate through the filter medium by the time in minutes.
- #8 volume of air is collected in a bag or steel or glass container.
- #11 A slope an increase or decrease in the magnitude of a property like temperature pressure etc
- #14 by adsorption onto container walls can be a problem with this technique. Essentially, all pollutants may be removed from an air sample by freezing or by liquifying the air in collectors maintained at a low temperature.