SAN FRANCISCO (KPIX 5) – There are many ways to obtain these air quality ratings that have given Bay Area residents an indication of how good the air is.
Looking at a hazy, ash-filled, gray sky, or even trusting your sense of smell, are not the best ways to determine how long you should be outside.
The Environmental Protection Agency is based on more than 250 surveillance sites across California and one in each of 9 Bay Area counties.
“They are placed in areas that should be representative of typical area conditions,” said Michael Flagg of the Bay Area Air Quality Management District.
The state-owned California Air Resources Board says it is gathering more air quality information than ever.
Air quality resources:
Purple Air – Track particles, sensors can register higher numbers than actual air quality.
Mary Prunicki, director of air pollution and health research at Stanford University, uses a combination of government regulatory monitors and low-cost commercially available sensors.
“What we’re trying to do now is get people to wear personal air pollution meters to try and get a better estimate of what people are actually exposed to.” , Prunicki explained.
The operation of expensive devices is quite simple. Air is drawn into the machine, then a computer network performs the analysis.
“There is a filter that is weighed in one monitor, then in the other type of monitor, the particles are deposited on the filter and the beta attenuation of those particles is measured by the sensors in the analyzer which results in a mass,” Flagg said.
Regulatory monitors, which cost tens of thousands of dollars, calculate particulate matter, gaseous pollutants like nitrogen dioxide and ozone, then publish AQI numbers every hour through AirNow, which is managed by the EPA.
As wildfires devastated millions of acres last month, the EPA and the U.S. Forest Service have launched a pilot program, adding data from low-cost sensors like Purple Air, which use laser and light technology to pump digits every ten minutes.
“Looking at a number of different things is how I look at air quality and I encourage people to do that too,” Flagg said.
The new charter is intended to help people make decisions to protect their health in the event of a fire.
The EPA will not use the data collected for this program to make regulatory decisions, as it relies in part on commercially available low-cost air quality sensors.
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