Environmental Health

1. Environmental Health KEMU 2014

2. Improvements in Public Health achieved in the 20th century • Water , food and milk sanitation • Reduced physical crowding • Improved nutrition • Central heating with cleaner fuels

3. Selected Wake-up Calls Environmental catastrophes • London killer smog (1952) - air pollution from coal burning • Minamata Disease ( 1953-61) - methyl mercury poisoning • Deaths from Typhoid fever (Philadelphia , PA 1906, 1913) - filteration and chlorination • Cuyahoga River (1969) - River caught on fire in Cleveland, Ohio • Bhopal (1984) - 16.5 tons of toxic pesticide released • Chernobyl (1986) - nuclear reactor accident • Milwaukee incident ( 1993) • - cryptosporidium in drinking water

4. Chemicals in the Environment • Increased production of synthetic organic chemicals (dyes, plastics and solvents etc.) - from less than 0.15 billion kg (1935) to more than 150 billion kgs - more than a 1000 fold in the US alone • Roughly 70,000 different synthetic chemicals are on the global market , many others are emitted as by products of their production , use or disposal

5. Air Ventilation • Composition of Air : - Nitrogen 78% in Fresh air – 78 % in expired air - Oxygen 20.93% in fresh air – 16.9 % in expired air - CO2 0.03 % in fresh air – 4.4% in expired air Trace Gases : minute amount of other gases like argon, krypton, xenon and helium are also present Air also contains water vapours, traces of ammonia and suspended matter such as dust ,bacteria , spores and vegetable debris.

6. Composition of air is remarkably constant – brought about by self cleansing mechanisms such as movement of air, sunlight , rain , atmospheric temperature and plant life. • Role of Air in Human Health • - vital role , performs various functions: • Supply oxygen for living organisms • Supply CO2 to plants • Helps in smelling • Helps in listening • Keeps body cool

7. Causes of Air Pollution • Changes due to respiration • Changes due to combustion • Dust and bacteria • Industrial pollutants • Organic decomposition and agricultural process

8. Changes due to Combustion • Occur as a result of : • Combustion in domestic fires: impurities are CO2, CO, SO2, H2SO4, CS2, H2S and moisture .% AGE of soot or smoke is greater in the use of firewood than in coal. • Use of Illuminates: common illuminates are coal gas , oils and electricity • Exhaust fumes from motor vehicles : contain CO (4 – 12%), CO2 (upto 100%), hydrocarbons (4%)

9. Dust and Bacteria • In ill ventilated rooms, atmospheric dust contains soot, silica , decaying leaf, animals excreta , eggs of parasites and bacteria • INDUSTRIAL POLLUTANTS fromfumes containing toxic gases or discharge of industrial wastes containing chemicals. • ORGANIC DECOMPOSITION AND AGRICULTURAL PROCESS: burning of refuse, agricultural activities such as crop spraying , pest control and nuclear energy programs also contribute to air pollution

10. Indicators of Air Pollution • SO2 • CO • OXIDANTS • SMOKE • NITROGEN DIOXIDE • LEAD • SUSPENDED PARTICLES

11. Harmful side effects of Air Pollution • Nausea , vomiting , fever etc. • Anemia, bronchitis, TB • Due to Chemicals : pneumoconiosis is a group of diseases due to inhalation of suspended dust particles. Leads to irreversible fibrosis in lungs eg. Asbestosis, silicosis, siderosis • Global Effects: - ozone depletion - green house effect - acid rain

12. Ozone Depletion • O3 – present at distance of 15- 50 km from earth (encircles the earth like a jacket) • Prevents waves of ultra violet radiation (from sun and is harmful to health) • Causes of Ozone depletion: • - depleted because of chlorofluorocarbons • - CFCs chemically interact with ozone and lead to thinning of ozone layer, present in ACs, aerosols, refrigerators • - hazards: UV rays cause skin cancers, melanomas, cataracts

13. Acid Rain • Areas where SO2 and NO2 are present in environment , the rain becomes acidic and called acid rain.SO2 and NO2 are produced as a result of fuel combustion and organic decomposition • Harmful side effects: • - damage to crops • - rusting of metals • -skin cancer • - damage to marine life • - lead poisoning due to damage to lead pipes • - discoloration of houses • Prevention: • - Treatment of Industrial smoke • - increases forestation • - treatment of vehicle smoke

14. Green House Effect • Small glass / closed huts in hilly areas or agricultural processing areas • Process which causes the surface of the earth to be warmer than otherwise, due to retention of heat/light waves in the green house • Enhanced effect of green house effect on a mega scale is referred to as ‘ Global Warming’ • In the absence of atmosphere , the temperature of earth on an average would be 30- 50 degrees F below than it is present , so life wouldn’t have existed

15. Causes of Green House Effect • Green house effect of atmosphere is due to green house gases • Energy from the sun heatens the earth surface , in return the earth radiates energy back into the space • Atmospheric green house gases trap suns outgoing energy so environmental heat is retained • Problematic when atmospheric concentration of green house gases increase . Annual increase ( CO2 0.4%, CH4 1%, CO .2%, CCL2, NO2, CFCs) • Harmful Side Effects: • - directly causes sunstroke, heat exhaustion • - heart pts. More at risk due to dehydration • - lung tissue damage - increased incidence of asthma • - Increased risk of infectious diseases

16. Water Resources • - dry soil • - poor water quality • - water quantity decreases overtime leading to decreased hydroelectric power generation • - elevation of 1.5m sea level – inundates 5000 sq. miles of land • Reduction in snow cover and melting of glaciers leads to increase in temperature • Deforestation and resultantly decreased wild life • Prevention : - decrease industrialization • - treatment of industrial smoke • - automobile emissions • - encourage forestation

17. Purification of Air • Carried out naturally • - Natural Methods: • - winds purify air by dilution • - sunlight purifies air by neutralizing bacteria and other noxious agents • - rain settles down suspended air particles • - plants purify air by photosynthesis • - Artificial Methods: • - Containment: means arresting polluted air at source , neutralizing and detoxifying and releasing the less toxic air into the atmosphere • - Replacement: of process leading to impurificationeg. Use of electricity in place of coal • - Dilution: establishment of green belts in residential areas is an attempt at dilution • - Disinfection: methods employed are UV Radiation – for disinfection of operation theaters and wards • Chemical Mist – triethylenevapours are effective bacteriacides • Dust Control: application of oil to hospital floors reduces accumulation of bacteria

18. Air Sampling and Inspection • Process: take a large wide mouthed jar • clean it with HCL/Distilled water • fill with distilled water completely and put lid correctly • take it to the place of sampling • pour off water • let it dry • again put the lid on and label the bottle for Time of sampling, place of sampling, purpose of sampling, location of place, person taking the sample, occupants at time of sampling, methods of ventilation at the place. Send it to a laboratory for examination for bacteria, carbonic acid, organic matter, CO2, CO, Ammonia, water vapours

19. Ventilation • Process of used and stagnant air with fresh and moving air • Standards: • there should be 1000-1200 cubic feet air space/person • 2-3 times air change/ hr in living rooms and 4-6 hours in workplace is important • windows should be 1/5 or 20% of total floor area • doors plus windows should be 40% of total floor area • ensure cross ventilation • Types: • - External • - Internal