Please annotate the 3 following sources for a paper on the causes, effects, and solutions to air pollution: 1) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.02165502) https://journals.plos.org/plosone/article?id=10.1371/journal.pone.01943643) https://www.atsjournals.org/doi/full/10.1164/ajrccm.162.supplement_1.maic-12