• 280 likes • 466 Views
OZONE ATMOSPHERIC POLLUTION. Ozone in urban smog. J (Hans) van Leeuwen. Ozone in the atmosphere. Ozone: stratospheric good; tropospheric bad Ground-level ozone resulting from NO x +VOC +sunlight Statospheric ozone is formed naturally and screens out harmful UV
E N D
OZONE ATMOSPHERIC POLLUTION Ozone in urban smog J (Hans) van Leeuwen
Ozone in the atmosphere • Ozone: stratospheric good; tropospheric bad • Ground-level ozone resulting from NOx +VOC +sunlight • Statospheric ozone is formed naturally and screens out harmful UV • Ozone pollution is a regional problem as it travels 100s of miles
Photochemical smog reactions • N2 + O2 2NO • 2NO + O2 2NO2 • NO2+ h NO + O • O + O2 + M O3 + M • O3 + NO NO2 + O2 These reactions are cyclical with little net O3 Hydrocarbons and water can remove NO
Ozone production from NOx Oxygen atoms freed from nitrogen dioxide by the action of sunlight attack oxygen molecules to make ozone. Nitrogen oxide can combine with ozone to reform nitrogen dioxide, and the cycle repeats.
Free radical reactions in air • O + H2O 2OH. • RH + OH. R. + H2O • R. + O2 RO2. • RO2. + NO RO. + NO2 • RO. + O2 HO2. + R’CHO • HO2. + NO NO2 + OH. Build-up of NO2, O3 and aldehydes results - also PAN – peroxyacetyl nitrate
Hourly Air Quality Report http://www.airnow.gov/
http://www.sonomatech.com/smogcity/ Use this to see the effects of weather And human activities on ozone levels
Ozone damage to lungs This photo shows a healthy lung air way and an inflamed lung air way. Ozone can inflame the lung's lining, and repeated episodes of inflammation may cause permanent changes in the lung.
Ozone Concentration (ppm) Air Quality Air Quality(8-hour average, unless noted) Index Values Descriptor 0.0 to 0.064 0 to 50 Good 0.065 to 0.084 51 to 100 Moderate 0.085 to 0.104 101 to 150 Unhealthy (sensitive groups)0.105 to 0.124 151 to 200 Unhealthy 0.125 (8-hr.) to 0.404 (1-hr.) 201 to 300 Very Unhealthy
This map shows ozone levels in the eastern United States on August 24, 1998
61-79ppb 80-99ppb 100-110ppb