Environmental Data Analysis EESC BC  3017

Lab: Dry deposition of particulate matter in New York City - Part 1

Introduction

You probably have noticed that when you leave the window of your room open for several days that a lot of black particles accumulate on your floor and window sill. Constantly, there is a flux of particles ‘raining’ down from the atmosphere. Some of these particles are washed out of the atmosphere by precipitation (wet deposition), some are deposited simply by gravitational settling in the atmosphere (dry deposition). Your task in this experiment is to determine the dry deposition flux in New York City using the provided ‘Scotch’ tape.

Lab instructions

Peel off one (only one!) layer of the provided tape and put it on something flat and heavy with the sticky side pointing upward as demonstrated in class and shown below.

Put it somewhere outside where you think, you will get a representative particle flux. Collect particles for 36 hours, as discussed in class. Then take the scotch tape and fix it on the provided drawing paper, so that at least 5 squares are covered. Intentionally, we do not want to give you a detailed list of instructions. We want you to spend some time thinking for yourself how to best conduct the experiment.

  1. We will determine times during which you should collect the samples in class.
  2. Think carefully about where to put the collection device.
  3. Which parameters may have an influence on the experiment? Please take notes of all the circumstances during the experiment.
  4. Count the number of particles in each of your 5 squares of your sample with the provided magnifying lens and write down the results on an extra sheet. Label the individual counts as XY1...XY5 (XY stands for your initials, two letters only!). Repeat counting particles of the 5 squares without looking at your previous results and note the counts. So you should have 10 numbers completed for each experiment you have performed when you come to class the next time after the experiment was done.


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Sampling sheet

Name: _____________________

Sample name (your initials, two letters only): _____

Sampling site:__________________________________________________

date and time of experiment; begin_______________ end :____________

Please note below whatever you find noteworthy about the site, as well as any parameters that you think may influence the experiment: