Determination of Precipitation Contamination Derek Anderson Teri Wilson

Hypothesis We believe that snow is purer than rain.

The Six Common Air Pollutants Ozone Particulate Matter Carbon Monoxide Nitrogen Oxides Sulfur Dioxide Lead

Nitrogen Oxides (NOx) Most common are: nitrogen dioxide (NO 2 ) and nitric oxide (NO) Primary sources are: kerosene heaters, un- vented gas stoves/heaters, and environmental tobacco smoke Causes eye, nose, and throat irritation National Ambient Air Quality Standard for Nitrogen Dioxide: <0.053ppm

Lead (Pb) A metal found naturally in the environment as well as in manufactured products Once taken into the body, lead distributes throughout the body in the blood and accumulates in the bones Lead exposure affects the oxygen carrying capacity of the blood National Ambient Air Quality Standard for Lead: <0.15μg/m 3

Collection Method Samples were collected outside of Teri’s garage Collected in clean, dry plastic containers Poured into sterile glass jars and covered securely Stored in the refrigerator until testing

Collection of Precipitation SampleType of Precipitation DateOutside Temperature Sample 1Freezing Rain F Sample 2Rain F Sample 3Snow F Sample 4Rain F Sample 5Rain/Snow Mix F Sample 6Snow F

Testing Dionex ICS-90 Ion Chromatography (IC) HP 8453 Diode Array UV/Vis Spectrophotometer Varian Inductively Coupled Plasma (ICP-OES)

IC Experiment Analyte of Interest – Nitrate and Nitrite Standards Used – 7 Anion Standard Standard 1 – 10 ppm Standard 2 – 15 ppm Standard 3 – 20 ppm Standard 4 – 25 ppm Standard 5 – 100 ppm

IC Parameters Pressure: 890 psi Flow rate: 1 mL/min Pressure Gauge: Slightly above 9

IC Nitrite Results TypePeak Height (μS) Standard 110 ppm3.433 Standard 215 ppm4.497 Standard 320 ppm4.907 Standard 425 ppm7.354 Standard 5100 ppm Sample 1Freezing Rain6.867 Sample 2Rain0.465 Sample 3Snow0.043 Sample 4Rain0.052 Sample 5Rain/Snow MixN/A Sample 6SnowN/A

Nitrite Calibration Curve

Calculated Nitrite Concentrations SampleTypeConcentration (ppm) Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix N/A Sample 6Snow N/A * Negative numbers denote negligible values

IC Nitrate Results TypePeak Height (μS) Standard 110 ppm2.308 Standard 215 ppm3.024 Standard 320 ppm3.552 Standard 425 ppm5.177 Standard 5100 ppm Sample 1Freezing Rain4.792 Sample 2Rain0.406 Sample 3Snow0.352 Sample 4Rain0.320 Sample 5Rain/Snow Mix0.472 Sample 6Snow0.288

Nitrate Calibration Curve

Calculated Nitrate Concentrations SampleTypeConcentration (ppm) Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix Sample 6Snow

UV/Vis Experiment Analyte of Interest – Nitrate Standards Used – Standard 1 – 5 ppm – Standard 2 – 10 ppm – Standard 3 – 15 ppm – Standard 4 – 20 ppm – Standard 5 – 25 ppm

UV/Vis Parameters Mode: Standard Task: Fixed Wavelength – 224 nm Data Type: Absorbance & Second Derivative Path Length: 1 cm

UV/Vis Nitrate Results TypeMean Absorbance Standard 15 ppm Standard 210 ppm Standard 315 ppm Standard 420 ppm Standard 525 ppm Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix Sample 6Snow

Nitrate Calibration Curve

Calculated Nitrate Concentrations SampleTypeConcentration (ppm) Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix Sample 6Snow * Negative numbers denote negligible values Results produced indicate method is not compatible and did not work for our purposes.

UV/Vis Nitrate Results TypeSecond Derivative Standard 15 ppm Standard 210 ppm Standard 315 ppm Standard 420 ppm Standard 525 ppm Sample 1Freezing Rain -- Sample 2Rain -- Sample 3Snow -- Sample 4Rain -- Sample 5Rain/Snow Mix -- Sample 6Snow --

Nitrate Calibration Curve

Calculated Nitrate Concentrations Even using the Second Derivative Mode, results indicated the method did not work and was not compatible for our purposes.

ICP Experiment Analyte of Interest – Lead (II) Standards Used – Blank – 0 ppm – Standard 2 – 40 ppm – Standard 3 – 60 ppm – Standard 4 – 80 ppm – Standard 5 – 100 ppm

ICP Parameters Search for Pb(II) at: – – – Used Pb(II) at 220 based upon UV/Vis wavelength obtained

ICP Lead Results TypeIntensity Blank0 ppm Standard 240 ppm Standard 360 ppm Standard 480 ppm Standard 5100 ppm Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix Sample 6Snow

Lead Calibration Curve

Calculated Lead Concentrations SampleTypeConcentration (ppm) Sample 1Freezing Rain Sample 2Rain Sample 3Snow Sample 4Rain Sample 5Rain/Snow Mix Sample 6Snow

Discussion UV/Vis data did not provide results of significance ICP yielded negligible concentrations of lead in samples Overall results support Freezing Rain to contain higher levels of Nitrogen Oxides (NOx)

Troubleshooting Sample Nitrite values are below IC sensitivities IC baseline is below 0.00 UV/Vis protocol not understood

Summary The original hypothesis that snow is purer than rain was rejected based on our findings No specific precipitation type yielded more pure results than another Only that Freezing Rain contained significantly higher concentrations of Nitrogen Oxides

References Evaluation of a second derivative UV/visible spectroscopy technique for nitrate and total nitrogen analysis of wastewater samples Michelle A. Ferree and Robert D. Shannon Water Research (1), p What Are the Six Common Air Pollutants. 2 April 2011.