County official admits to manipulating air quality forecasts
August 1, 2011
Manipulations of air quality forecasts in a south San Luis Obispo County region caused as many as 100 days to be given “yellow,” moderate alert, rather than “green,” safe air quality, status.
An official at a San Luis Obispo County Air Pollution Control District board meeting last week admitted the air quality status in Nipomo and Oceano had been tweaked to project moderate alerts—requiring caution in asthmatics—on at least 100 days when they should have been green, or safe.
The Air Quality Index (AQI), a federal standard, simplifies pollution levels on any given day to a color code for public health notices: “green” is good; “yellow” signifies a moderate alert; “orange” is unhealthy for sensitive groups; “red” represents unhealthy for everyone; and “purple” means the air is very unhealthy to breathe.
At a July 27 district board meeting, Air Pollution Control Officer Larry Allen confirmed they have been adding five points to the daily air quality index forecast for the Nipomo and Oceano region.
Offsetting the index has frequently resulted in wrong predictions, issuing “yellow,” or moderate alerts, when in actuality at least 100 of those alerts were “green” safe air days.
The fact was disclosed during the public comment session of the meeting, where Kevin Rice, an advocate for off-road recreation at the dunes, presented an analysis of air quality forecasts compared to final daily actual indexes over the last 10 months.
Rice found the air quality predictions appeared to be artificially fixed, in some cases making people believe they were breathing bad air.
In the Nipomo West region, nearly one-third of the time the district was informing the public pollution levels would be moderate, coded as a “yellow” health alert, when in fact it turned out to be a “green,” healthy air day. At that rate, 100 days a year are miscoded to a higher level, Rice explained noting that this is the only area of the county where the numbers are increased.
Allen confirmed Rice’s findings but defended the strategy as “playing it safe” to protect children and sensitive members of the public.
“We have gone on the side of conservatism, and gone slightly down below, so that we can forecast a violation of the state standard using the AQI system,” Allen said. “I actually kind of like the results that he [Rice] showed because you know, we’re pretty darn close in our forecast. So that explains the difference.”
However, the district uses the federal AQI color system rather than a state program to communicate air pollution levels.
In addition, within the last year more than 90 percent of the “yellow” health alert days for the Nipomo West region were caused because of PM 2.5 (particles less than 2.5 micrometers in diameter) pollution levels. And the state does not have a daily standard for this pollutant. The Nipomo West region includes Nipomo, west of U.S. Highway 101, Nipomo Mesa, Oceano and the Oceano State Park.
Through nine stations around the county, the district constantly monitors levels of pollutants in the air including ozone, particulate matter, nitrogen oxides, sulfur oxides and carbon monoxide.
A moderate forecast means the air quality is acceptable, but for people who are unusually sensitive to ozone, such as those with severe asthma, they may experience respiratory symptoms. These people may opt to stay indoors and limit physical activity on these code “yellow” days, as opposed to code “green” forecasts where air pollution is expected to pose little or no risk.
Critics, like Rice, contend the public is being misinformed and that forecasts should be distributed as true and actual, not inflated, predictions.
Some county schools participate in the pollution control district’s “Clean Air Kids” marketing program and are regularly alerted of the forecasted air quality color code. Some schools post colored flags to inform students and parents of whether it is safe to be outside and breathe the air.
Daily air quality forecasts are also distributed to residents through the Environmental Protection Agency’s (EPA) Air Now website and email subscriber system, in addition to other media when unsafe air conditions are anticipated.
Distributed through Air Now, a recent forecast that predicted code “yellow” and windy conditions warned: “Very sensitive individuals such as infants, as well as children and adults with existing respiratory or heart conditions may experience adverse health effects during blowing dust periods. If blowing dust and sand is visible in the air, county officials recommend all adults and children avoid strenuous outdoor activity, remain indoors as much as possible, and set any heating/air conditioning/ventilation systems to recirculation.”
“The public relies on these forecasts and largely does not see the actual AQI reported at the end of the day, resulting in misconception, alarm and misinformation about our local air quality,” Rice said.
Rice has complained to the EPA and informed some local school districts of the bias in forecasting.