My 4-year-old son gets frequent colds that develop into bronchitis because his lungs are so compromised by the air quality here," says L.A. resident Samantha Slaven. "We have to routinely use a nebulizer every time he gets sick." Because of nitrous oxides and carbon monoxides emitted by Chinese factories, L.A. endures an extra 24 hours each year in which air quality exceeds federal ozone standards.