Q. The dust from road construction seems worse than it ever has been on Division Street. There's a coat of dust on everything. People have to keep their doors and windows closed. Children can't play outside. Why is it so bad this year? What is the dust made of and what kind of health hazard exists from breathing or ingesting this stuff? — William, Davenport
A. The city of Davenport is using a process called cape sealing. According to a May 11 news release provided by Jennifer Nahra, communications director, "Drivers may encounter dust and gravel from the process.
"Drivers on a cape sealed roadway will experience limestone dust, similar to driving on a gravel road. Motorists are encouraged to drive a bit slower and allow for more stopping distance. The roads will remain open during this entire time, because driving on the roads actually helps the process by embedding the limestone into the oil."
"To help mitigate dust effects over the weekend, the City of Davenport Streets Division will be frequently watering these roads during peak activity."
We contacted the Iowa Department of Public Health regarding your question about possible health hazards. Stuart Schmitz, state toxicologist said, "There are new OSHA rules regarding the standards of exposure. The new permissible exposure limit (PEL) for respirable crystalline silica is 50 micrograms per cubic meter of air (50 ug/m3) averaged over an 8-hour shift. This applies to the workers, and can be achieved with engineering controls or respiratory protection.
"This is a link to these rules: https://www.osha.gov/silica/. City and county officials should be aware of these rules and may wish to not only require these standards to be implemented when this rule goes into effect, but to require some type of controls to prevent excess exposure to the public.
"The new occupational level of silica dust exposure is based upon health and epidemiological studies that have completed on individuals who have been exposed to respirable silica levels over many years of working in that industry. One of these studies estimated 2 percent of workers exposed at 50 ug/m3 for 40 years developed silicosis. Another study estimated that a worker is exposed at 50 ug/m3 for 25 years had a 9 percent chance of developing silicosis. In an additional study an exposure level of 50 ug/m3 was estimated to cause an addition risk ranging from 0.4 percent to 0.9 percent after 40 years of exposure.
"I am uncertain of the impact that the short term exposure to fine particles of silica dust would have on the long term health impact of community members that were exposed to the dust from the road construction activities. The development of silicosis would take many years of exposure. There will be short term health impacts such as eye and lung irritation. People will underlying respiratory issues and the very young and very old will be impacted to a greater degree."
We also contacted Genesis Health Systems and UnityPoint Health regarding your question. To view their responses, visit qctimes.com/askthetimes.