Document Type


Publication Date

Winter 12-10-2017

Publication Title

Air Quality, Atmosphere, and Health







Publisher Name

Springer Netherlands

Publisher Location



Aerosol, trace gas, and meteorological data were collected in Chicago, Illinois during 2010–2012 summer air studies. Ozone, nitrogen oxides, acetate, formate, chloride, nitrate, sulfate, and oxalate concentrations as well as temperature, wind speed, wind direction, and humidity data were explored by both principal component analysis (PCA) and canonical correlation analysis (CCA). Multivariate statistical techniques were applied to uncover existing relationships between meteorology and air pollutant concentrations and also reduce data dimensions.

In PCA, principal components (PC) revealed a relationship of ozone and nitrate concentrations with respect to temperature and humidity, coupled with transport of species from the south in relation to the sampling site (PC1). PC2 was a measure of secondary aerosols but also suggested acetate and formate presence was a result of primary emissions or transport. Both PC3 and PC4 contained residual information with the former representing days of lower pollution and the latter representing northerly wind transport of chloride, nitrate, and ozone to the sampling site.

In CCA, three canonical functions were statistically significant. The first indicated high temperature and low wind speed had a strong linear relationship ozone, oxalate, and nitrogen oxides concentrations whereas the second function showed a strong influence of wind direction on acetate, formate, and chloride concentrations. Residuals of temperature, wind speed, trace gases, and oxalate also were in the second function. The only new information in the third function was humidity. Overall, PCA and CCA bring forth multi-variable relationships, not represented in descriptive statistics, useful in understanding pollution variability.


ISSN 1873-9318


Author Posting © Springer Nature B.V., 2017. This is the author's version of the work. It is posted here by permission of Springer Nature B.V. for personal use, not for redistribution. The definitive version was published in Air Quality, Atmosphere, & Health, Volume 10, Issue 10, December, 2017.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.