Ozone Investigations on the Lower Troposphere

1. Ozone Investigations on the Lower Troposphere by Farhana Nabi Abstract Tropospheric Ozone Stratospheric Ozone Data/Results • Considered as “good ozone”. • Lies from 12 km – 50 km above the sea level. • Formation: • Stratospheric ozone absorbs UV radiation , preventing in turn, skin cancer and cataracts. • It occurs naturally because it is not created by manmade pollutants. • It protects crop and marine life. Continuing investigations of ozone concentrations in the lower troposphere are underway to  ozone concentrations in New York City. The objective of these experiments is to determine factors related to the variability on the concentrations of ozone in the atmosphere. The emphasis of this investigation is on the relationship between the urban heat island effect and ozone concentrations in the New York City metropolitan. Relevant parameters include ozone partial pressure, temperature, humidity, pressure, ozone mixing ratio, wind direction, and wind speed. The data is retrieved from sounding launches at the Brookhaven National Laboratory. The two main instruments for the soundings are a radiosonde and an ozonesonde.  The ozone data is also being correlated with satellite imagery and surface ozone observations from the EPA. • Considered as “bad ozone”. • Lies up to 12 km above the sea level. • Some of the this ozone comes from the stratosphere. However, most of it is created by the chemical reactions between nitrogen oxides and volatile organic compounds (VOCs). • It is a main ingredient of smog. • It damages and reduces lung function. • It aggravates existing lung conditions such as asthma, emphysema, and bronchitis. • It causes chest pain, coughing, congestion. • It reduces crop and forest yield. Figure 2 Figure 1 Figure 3 Figure 1 http://www.odec.ca/projects/2006/pete6o2/Pages/Background.html Figure 1 Figure 4 Figure 5 Figure 6 Background Material Figure 8 Figure 9 Figure 7 What is Ozone? Methodology • A highly reactive gas found in both the troposphere and stratosphere. • It consists of three oxygen atoms bound by a single covalent bond and a double covalent bond. In order to gather data on the concentrations of ozone in New York City, several sounding balloon were launched at Brookhaven National Laboratory. Figure 10 Figure 11 Figure 12 What is the Urban Heat Island Effect? Ozonesonde • The urban heat island effect describes metropolitan areas that are hotter than surrounding rural or suburban areas. • In these areas the temperature is higher than that of surrounding areas, there is more pollution, and a higher energy demand. • This affects ozone concentrations because tropospheric ozone is created by reactions between VOCs and nitrogen oxides in the presence of sunlight and heat, therefore urban heat islands are centers for the growth of tropospheric ozone. • It is an electrochemical cell developed by Walter Komhyr which measures ozone concentration. • Air enters the intake tube, goes through the cathode solution where the ozone in the air reacts with the Potassium Iodide solution to create Iodine. The iodine then passes through the ion salt bridge to the anode cell. • This process produces an electrical current that is proportional to the ozone concentration of the outside air. Figure 13 Figure 14 Conclusion Radiosonde The objective was to determine how meteorological variables affect ozone concentration and to make preliminary observations on the effects of the urban heat island (UHI) on ozone concentrations in New York City. According to the data (Figures 5, 6, 11, and 12) it is determined that temperature and ozone concentration are directly related. However, this correlation is not always exact because other factors such as pressure and altitude also change ozone concentrations. From Figures 5 and 11 it is determined that altitude and ozone concentration are inversely related. From Figures 6 and 12 it is observed that ozone concentration is directly related to pressure. Although there are several factors related to ozone concentration the most significant is temperature. If we compare Figures 1 and 7, we see that in the New York City metropolitan area there was a significant increase in ozone concentration despite there being a temperature difference of only about 5⁰F. From this observation and our knowledge of urban heat islands a hypothesis was drawn that the New York City urban heat island will be a center for the growth of tropospheric ozone. However, when data regarding the temperatures in New York City and it’s surrounding areas was collected, it was observed that even though New York City is an urban heat island, its ozone concentrations were less than that of its surrounding areas. Looking at Figures 13 and 14 it is observed that while the low temperatures in New York City are higher than that of the surrounding areas, the high temperatures in New York City are often lower than that of the surrounding areas. While we are unsure of the reasons why, one theory we came up with was that the changes in temperature and ozone could be due to the fact that New York City is surrounded by water; therefore, in the summer it will be cooler than areas surrounded by land. It can be concluded that, although New York City is an urban heat island, this was not a major factor in the ozone concentration changes in New York City. To draw further conclusions and support our observations, soundings at the Brookhaven National Laboratory will continue to take place and surface ozone concentrations will continue to be observed. • The radiosonde, developed by Robert Bureau, measures pressure, temperature, humidity, wind speed, wind direction, geographical position, and altitude. • It also transmits this information via radio frequency to ground station. • It can be powered by a dry cell battery or a wet cell battery and is interfaced with the ozonesonde. A. Ozonesonde B. Ozonesonde C. Radiosonde http://eetd.lbl.gov/l2m2/cool.html Acknowledgements: Dr. Shermane Austin Dr. Leon Johnson Rita Barley Karina Alventosa Sydnee Cumberbatch Natasha Bollers Jermaine Reid Brandy Busick Sources http://medgareverscollegecuny.basecamphq.com/projects/7294823/file/8471649/ozone%20and%20heat%20island_new.pdf http://www.epa.gov/heatisland/ http://cimss.ssec.wisc.edu/wxwise/heatisl.html http://www.noaa.gov http://www2.fz-juelich.de/icg/icg-2/wccos