PM Follow-Up: the 2005 Spike and the Midlothian Drop
(Note: Downwinders sent out an air quality alert on Monday urging folks to send their comments 1) into EPA to support the new PM standard, and 2) the federal ATSDR in regards to its "health consultation" in Midlothian. The correct address for the PM comments is "a-and-r@docket.epa.gov" – the same as the alert, but apparently the the whole address didn't get underlined. Use the complete address and you shouldn't have any problem. The ATSDR address for comments used in the alert is cut and pasted from the agency's own website, but was rejecting comments Monday afternoon for some reason. Complaints have been made and we hope they'll actually be allowing comments on Tuesday.)
In covering the PM 2.5 standard announcement, a lot of attention was paid by the media to the fact that only a handful of counties in the US would not be able to meet the new number by 2020. The Obama Administration worked hard to send that message in order to preempt the kind of backlash that killed last year's new smog standards. But what are the actual levels now and how close or far is DFW from ever having to worry about being in non-attainment for PM pollution?
The new standard is an annual average of 13 micrograms per cubic meter of air, expressed as ug/m3. As far as we can tell from the monitoring records TCEQ keeps online, DFW hasn't come close to exceeding that number. But that's not really as conclusive as it might first sound. There are only two PM 2.5 monitors located in the heart of the DFW metropolitan area. One is on /Hinton Street near Mockingbird and Harry Hines in Dallas and the other is at the Haws Athletic Center location just north of downtown Ft. Worth. All others are in far southern Ellis County, Kaufman County, or Johnson County and act as "background" monitors to track PM pollution coming in or leaving urban DFW. In contrast, there are at least nine ozone monitors located in urban/Suburban DFW .
Tracking the two central city core monitors over the last ten years shows a slow but steady rise in the average PM 2.5 levels being recorded, staring at a little below 9 ug/m3 in 2002 and ending with an 11.01 last year. That's an increase of almost 2 ug/m3 in a decade. 2011 was a drought year and so there was probably more dust in the air. But records show other years where annual averages were in the high-10 to 11 ug/m3 range. What they also show is that these higher levels all come after 2005. In fact, across the board, at all the DFW monitors recording PM levels from 2004 to 2005, there was a statistically significant jump from annual averages in the high 8 ug/m3 range in 2004 to over 11 ug/m3 by the end of 2005. And while some monitors came back down, the two central city monitors have stayed up – particularly at the Ft. Worth site. So what happened in 2005? There was a Mexican volcano eruption that summer, but it ended. The higher PM averages in North Texas didn't. It was too soon to see the effects of urban drilling, although that may play a part in keeping the Ft. Worth levels higher now. Whatever it was, it makes a clear bright line that separates the pre-2005 lower numbers from the post-2005 higher ones.
Last year's average of 11.58 ug/m3 at the Dallas site was the highest at that monitor, or any other, in the last ten years. It's less than 1.5 ug/m3 away from breaking the brand new PM standard of 13. That same monitor has already seen a 2.25 ug/m3 increase in annual averages since 2002.
EPA says don't worry, but we'd keep our eyes on those long term trends.
The Obama administration is banking on the impact of new power plant rules, cement plant standards, and other emission-affecting regulations to lower PM levels over the next eight years. And that could be a good bet. One of the things that also sticks out from the limited amount of DFW PM data is how much of a drop there's been at the Midlothian monitor located north of the TXI cement plant over the last five years after reaching a peak in 2008. That was the year TXI decided to shut down its four obsolete wet kilns that burned hazardous wastes and rely solely on its newer and generally less polluting dry kiln. In 2008, the Midlothian monitor recorded an annual level of 10.7 ug/m3. Last year it recorded an annual average of 8.0. That's progress.