On the worst pollution day that year, when particulates inched toward unsafe levels, asthma deaths jumped 40 percent and asthma attacks increased 36 percent. Researchers don't know exactly what causes asthma. Even in Phoenix, where people worry increasingly about the Brown Cloud, some air pollutants have declined. Carbon monoxide levels have not violated federal health standards for years. Ozone levels have stayed within the guidelines for three years.
Particulates remain a problem, however, worsened by increasing vehicle exhaust and construction.
To clear the air, Gov. Jane Hull's Brown Cloud Summit has proposed requiring a cleaner burning diesel fuel, banning leaf blowers and other measures. Lawmakers are debating the plans. Something must be done, the task force concluded. Abstract goes here. All rights reserved.