DESCRIPTIVE ANALYSIS OF PM(2.5) AND PM(10) AT REGIONALLY REPRESENTATIVE LOCATIONS DURING SJVAQS AUSPEX/

SJVAQS/AUSPEX acquired PM(2.5) and PM(10) samples at ten sites in Cent ral California for five ozone episodes over 14 intensive sampling days . Four sample sets per day were acquired for 5 and 7 h durations and m easured for particle mass; elements; water-soluble chloride, nitrate, sulfate, ammonium, sodium, and potassium ions; and organic and element al carbon. Gaseous ammonia, nitric acid, and sulfur dioxide concentrat ions were acquired with absorbent filter material. To guard against co ntamination of these gases after sampling, the filter packs were seale d and refrigerated prior to analysis. Crustal species such as aluminum , silicon, calcium, titanium, iron, and calcium, were found in coarse particles at most sites. Substantial amounts of sodium and chloride we re detected in the coarse particle fraction at the coastal Point Reyes site. Organic carbon and sulfate were the most abundant species in th e PM(2.5) fraction. Elemental carbon concentrations were low at all si tes. Only one 24 h average PM(0) concentration exceeded the U.S. PM(10 ) standard of 150 mu g m(-3) during the study period, and this occurre d at the agricultural-oriented Buttonwillow site. The highest concentr ations of most chemical species were found at sites in the Southern Sa n Joaquin Valley. Copyright (C) 1996 Elsevier Science Ltd