6. Speciation Analysis and Source Apportionment

We want to do the composition of PM, you have 2 options again you can look at organic or inorganic. So we are looking at organic you know the instruments that are used for organic we saw that already in terms of the water, if you want to look at organic chemicals, there are a set of instrumentation that you can use starting from the GC or LC or any of those instrumentation.

In speciation analysis, we focus on identifying and quantifying different types of particulate matter (PM) found in the air. Two primary types of composition are examined: organic and inorganic. Organic analysis involves using various instruments such as Gas Chromatography (GC) or Liquid Chromatography (LC) to detect organic chemicals in air samples. These tools help in extracting organic components from PM for further investigation.

Think of PM as a mixed bag of different candies. If you want to know how many chocolates, gummies, and sour candies are in the bag, you need to separate and analyze them. Similarly, in environmental science, researchers separate PM into organic and inorganic components to understand their sources and effects.

So, let us say a particle is there, this particle itself maybe an organic particle, which means that you have to dissolve the entire particle into a solvent. So, that is one option. Second option is if the organic material is adsorbed on other particles and when you have to pull these particles out, you have to dissolve or desorb.

When analyzing organic PM, scientists have two main methods to extract the necessary information. The first method involves dissolving the organic particle completely into a suitable solvent. The second method is when the organic material is attached to other particles; in this case, it is necessary to either dissolve or desorb the organic component to analyze it effectively.

Imagine trying to extract honey that has stuck to a piece of bread. You can either scrape it off (desorb) or mix the whole bread into warm water to dissolve the honey. In air pollution studies, similar techniques are used to pull out organic materials from particles in the air.

When you do organic analysis for PM we do what is called us OC, EC, analysis is called organic carbon, elemental carbon. What we mean by organic carbon is the carbon that is part of CHNO and so on.

In PM analysis, distinguishing between Organic Carbon (OC) and Elemental Carbon (EC) is crucial. Organic Carbon refers to carbon that is part of organic compounds (like those containing carbon, hydrogen, nitrogen, and oxygen), while Elemental Carbon refers to pure carbon forms, often emitted from incomplete combustion processes. Understanding these components helps researchers identify pollution sources.

Think of OC as ingredients in a soup (various nutrients) and EC as the pots and pans you cook with (pure carbon). Just like evaluating what's in your soup can tell you about what you eat, analyzing OC and EC provides insights into pollution sources and impacts.

In inorganic analysis, you can do 2 kind of things you can do elemental analysis or you can do ions, you can get what is present on the particle by either of these methods.

Inorganic analysis of PM focuses on two major approaches: elemental analysis and ion analysis. Elemental analysis determines the presence of specific elements such as sodium, potassium, and heavy metals in the particulate matter. In contrast, ion analysis focuses specifically on ions, such as cations and anions, to identify their concentrations in the samples. Together, these methods provide a comprehensive understanding of the inorganic content of PM.

It's like a toolbox. The elemental analysis gives you the individual tools (like each hammer or screwdriver), while ion analysis focuses on smaller bits like screws and nails. Together, they help you understand all the hardware you have to work on a project.

So the filter paper choice depends on what you want to analyze you cannot do one for all, you can do one for all but it will be full of errors.

Choosing the right filter paper is essential for collecting PM samples accurately. Depending on whether one is analyzing for organic compounds, metals, or ions, different types of filters (like quartz, glass, or polymer-based filters) are preferred. Using the wrong filter could lead to contamination or loss of data accuracy, so specific filters tailored to each analytic method are crucial.

Imagine trying to filter tea through different materials. If you use a paper towel, it's likely to tear, letting bits of tea leaves through, while a fine mesh strainer will catch all leaves without leaking. Similarly, picking the right filter ensures you only collect the desired particles.

So, to do this there is what is called as the speciation sampler commercially available, so it is a multi-channel sampler.

Multi-channel speciation samplers are specialized devices that simultaneously collect multiple types of particulate matter for analysis. These devices allow researchers to gather data on various pollutants from the same location at the same time, improving efficiency and accuracy in source apportionment studies.

Think of this multi-channel sampler as a car with several compartments, each designed to keep different items separate (like groceries, sports gear, and kids’ toys). It allows you to gather all your needs in one trip without mixing them up, just as the sampler collects various air pollutants without interference.

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