I'm doing a research project for school on air pollution and part of it is studying pollution caused by aviation and I have found a table of data for the emission indices of various pollutants but I'm not 100% certain, if I'm correctly reading the numbers.

The unit is $\mathrm{g\, kg^{-1}~of~fuel}$ and the numbers are like 1.64E-02 or 2.25E+00. I'm interpreting it as E being for Exa, so in short scale 1.64E would be 1.64 quintillion and that it means 1.64 quintillion particles per g per kg of fuel. Is that the correct meaning? I have no idea what the second bit of the numbers means so please could you explain for me?

screen shot of table

  • $\begingroup$ @Martin-マーチン Added image $\endgroup$ – A. Student Jan 14 '16 at 5:12

The format refers to a quite common scientific notation, where the $\mathrm{E}$ refers to exponent of $10$. It is often used when superscripted values become tedious to read and or write. It is widely known in computational sciences and was introduced for an easier display of huge or tiny numbers.

You can interpret the $\mathrm{E}$ as "times ten raised to the power of", hence the format can be interpreted like this: $$n\mathrm{E}m = n\times10^{m}$$

Therefore $1.64\mathrm{E}-02 = 1.64\times10^{-02}= 0.0164$ or $2.25\mathrm{E}+00=2.25\times10^0=2.25$.


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