eMission control – Focus: PM 2.5 in the San Joaquin Valley

It’ll be really interesting come American Lung Association “State of the Air” (2016) reporting time and learning what the ALA’s assessment of fine particulate matter pollution (PM 2.5) is for the San Joaquin Valley which, by the way, is consistently ranked the worst in the nation for this particular pollutant. Will the Valley once again be declared the most troublesome spot for soot? We should know in the coming months.

Until that time is upon us, here are several Valley PM 2.5-related facts.

Those paying close attention to (tracking) the region’s fine particulate matter trends, should take some comfort in knowing that with regard to this harmful emission’s presence in area air, between Aug. 2015 and Feb. 2016, 57 exceedances of the average, 24-hour PM 2.5 (at highest site) National Ambient Air Quality Standard were recorded. This compares only slightly more favorably to the period from Aug. 2014 to Feb. 2015 which recorded 59 such exceedances.

Fireplace_Burning[1]Moreover, with regional fireplace and woodstove wood-burning regulations in effect from the beginning of November until the end of February (keep in mind that not everyone in the Valley who uses a fireplace or woodstove or both, strictly follows the rules), between Nov. 1, 2014 and Feb. 28, 2015, the number of said exceedances numbered 56. Meanwhile, between Nov. 1, 2015 and Feb. 29, 2016 (2016 a leap year), exceedances totaled 27, less than half what there were in the previous year for the same period.

As to the improvement, the San Joaquin Valley Air Pollution Control District in a news release responded: “While registered devices could be used more often, the Valley saw significant improvements this winter and the ‘No Burning For All’ curtailment that prohibits both registered and non-registered devices from burning when PM 2.5 levels become critically unhealthy, was not needed. Comparatively, last winter, there were a total of 36 ‘No Burning For All’ curtailments throughout the air basin. Additionally, there were far fewer days during which the fine-particle level exceeded the federal health standard of 35 micrograms per cubic meter.”

Presumed to partly account for that marked improvement were more favorable meteorological conditions – between Oct. 1, 2015 and Feb. 28, 2016 compared to that which fell during this same period between Oct. 1, 2014 and Feb. 28, 2015, the Valley received essentially double the rainfall amount (or 9.95 versus 4.51 inches, that is, in the Fresno area, at least). As it may relate, there was no mention made whatsoever in the news release in question that weather could have been a contributing factor in said air quality improvement.

In Aug. and Sept. 2015, to try to explain why the reason for the higher-than-usual number of exceedances, it is probably safe to say that this can be attributed mostly to the presence of wildfires burning in the Sierra Nevada Mountains during this time, smoke from these drifting into parts of the Valley at times, more so on the Valley’s east side. What’s more, in California and the south state especially, the month of July 2015 was uncharacteristically wet, which probably helped prevent exceedances related to the fires from numbering higher.

All in all, for 2015 vs. 2014, it was pretty much even-steven with a total of 61 exceedances tallied last year versus 2014’s 59.

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