On the impact of pollution and it's causes, this article on climate and air pollution explains about some studies are taking place.

In a new study released May 3, 2017 a group from the University of Wisconsin Madison found that in the summer increased electricity demand may play a key role in high levels of ozone, particulate matter and other pollutants.  As shown in the pictures provided in this article, it refers to portable , window air conditioning units. The study shows that although scientists have long known that air pollution is highest in the summer days, few studies have been made on it's contribution to air pollution. The studies show that air conditioning causes emissions of sulfur dioxide, nitrogen oxides and carbon dioxide to increase by hundreds to thousands of metric tons, or 3 to 4 percent per degree Celsius (or 1.8 degrees Fahrenheit). Tracy Holloway who is a professor of environmental studies at the Nelson Institute says researchers plan to continue to study the impact of electricity emissions with other factors affecting pollution formations. It is important to be able to learn more from studies like these to help improve the design and overall performance and impact of air conditioners.       Read more at: https://phys.org/news/2017-05-cool-summer-air-pollution.html#jCp   From <https://phys.org/news/2017-05-cool-summer-air-pollution.html>;