Similarities and differences in PM10 chemical source profiles for geological dust from the San Joaquin Valley, California

Chow, Judith C.; Watson, John G.; Ashbaugh, Lowell L.; Magliano, Karen L.

doi:10.1016/s1352-2310(02)01021-x

Cited by 132 publications

(96 citation statements)

References 13 publications

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“…Organic mass [OM = 1.4 × OC to account for unmeasured hydrogen, nitrogen, sulfur, and oxygen, see Watson (2002) for justification] and nitrate were the next largest components, accounting for 18-22% and 15-24% of PM 10 , respectively. Ammonium sulfate, EC, salt (available from Tulare dry lake bed, Chow et al, 2003), and trace elements constituted the remaining PM 10 mass.…”

Section: Resultsmentioning

confidence: 99%

Characterization of Ambient PM10 Bioaerosols in a California Agricultural Town

Chow

Yang

Wang

et al. 2015

Aerosol Air Qual. Res.

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Ambient bioaerosols in PM 10 samples were measured at three sites in Corcoran, an agricultural town in the southern San Joaquin Valley (SJV) of California, during fall of 2000 corresponding to the cotton harvest season. Elevated bioaerosol concentrations were measured near grain elevators (GRA site) and a cotton handling facility (BAI site) as compared to levels in a residential community (COP site), ~2 km northeast of these sources. Average endotoxin levels (13 ± 17 EU/m 3 ) at the grain elevator site were three to eight times higher than averages at the nearby cotton-handling and residential sites. The highest level (47.6 EU/m 3 ) at the grain elevator site was about half of the exposure limit of 90 EU/m 3 set by the Dutch Expert Committee on Occupational Safety. Particle counts of fungal spore (66,333 particles/m 3 ) and pollen grain (2,600 particles/m 3 ) concentrations were more than double those reported in the literature. Average fungal biomarker concentrations of 170 and 131 ng/m 3 for arabitol and mannitol, respectively, were 1-2 orders of magnitude higher than those from nonagricultural areas. The low correlation (r < 0.11) of three fungal markers (i.e., (1→3)-β-D-glucan, arabitol, and mannitol) with fungi counts is consistent with findings by others and indicates that these are insufficient as surrogates to represent fungal exposure. Agricultural activities contributed measureable amounts to PM 10 mass and organic carbon (OC), dominated by fungal spores (i.e., 5.4-5.8% PM 10 mass and 11.5-14.7% OC). The sum of fungal spores, pollen grains, and plant detritus accounted for an average of 11-15% PM 10 and 24-33% OC mass. Bioaerosols can be important contributors to PM 10 mass in farming communities similar to Corcoran, especially during intense agricultural activities.

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Section: Resultsmentioning

confidence: 99%

Characterization of Ambient PM10 Bioaerosols in a California Agricultural Town

Chow

Yang

Wang

et al. 2015

Aerosol Air Qual. Res.

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“…Each of these sources involves either fossil fuel combustion or other human activities in the immediate vicinity of dust sources. Therefore, compared to natural dust, anthropogenic dust aerosols contain higher anthropogenic-originated elements, such as elemental carbon (from fossil fuel or biomass combustion) or heavy metals (such as Zn, Pd and Cu) from industrial operations (Chow et al, 1993(Chow et al, , 2003Reff et al, 2009). For instance, high levels of black carbon, Pb, Zn are found in paved road particles while high levels of nitrate (NO 3 ), Cr and Ni are found in unpaved road dust (Chow et al, 1993).…”

Section: Approach To Identify Local Dust Recordsmentioning

confidence: 99%

“…For instance, high levels of black carbon, Pb, Zn are found in paved road particles while high levels of nitrate (NO 3 ), Cr and Ni are found in unpaved road dust (Chow et al, 1993). Similarly, OC, K and Ca concentrations are high in animal husbandry dust and Ti, V, Mn concentrations in construction dust (Chow et al, 2003). Therefore, we use the concentrations and enrichment factors (EFs) of anthropogenic pollutants as the indicators to distinguish natural dust from anthropogenic dust.…”

Section: Approach To Identify Local Dust Recordsmentioning

confidence: 99%

Long-term dust climatology in the western United States reconstructed from routine aerosol ground monitoring

Tong

Wang

et al. 2012

Atmos. Chem. Phys.

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Abstract. This study introduces an observation-based dust identification approach and applies it to reconstruct longterm dust climatology in the western United States. Longterm dust climatology is important for quantifying the effects of atmospheric aerosols on regional and global climate. Although many routine aerosol monitoring networks exist, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population) or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose an approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1) high PM 10 concentrations; (2) low PM 2.5 /PM 10 ratio; (3) higher concentrations and percentage of crustal elements; (4) lower percentage of anthropogenic pollutants; and (5) low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado). During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000- The monthly frequency of dust events shows a peak from March to July and a second peak in autumn from September to November. The large quantity of dust events occurring in summertime also suggests the prevailing impact of windblown dust across the year. This seasonal variation is consistent with previous model simulations over the United States.

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“…Metal elements such as Al, Fe, and Mg found mainly in coarse particles (> 2 µm) were abundant constituents of all road dust and soil particles. Therefore, these results clearly suggest that these mineral aerosols are likely Table 2 Correlation between traffic volume and chemical components during the sampling periods generated by the resuspension of road dust and soil (resuspended dust) (21) . Moreover, increase in the number of heavy-duty vehicles on the road probably increases the proportion of the road-dust contribution to SPM mass.…”

Section: Average Concentrations Of Major Metal Componentsmentioning

confidence: 91%