Acid aerosol measurements at a suburban Connecticut site

Keeler, Gerald J.; Spengler, John D.; Castillo, Raymond A.

doi:10.1016/0960-1686(91)90066-g

Cited by 41 publications

(22 citation statements)

References 25 publications

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“…Therefore, a low level of aerosol acidity was found in the Lanzhou (∼65 nmol m −3 ) and Guangzhou (∼70 nmol m −3 ) samples. The average aerosol acidity levels of PM 2.5 measured in Hong Kong (∼75 nmol m −3 ) and the US (Connecticut ∼42 nmol m −3 ; North US ∼45 nmol m −3 ) were comparable to those in the ammonium-rich samples of Lanzhou and Guangzhou, but much lower than those in the Beijing and Shanghai samples (Pathak et al, 2003;Speizer,1989;Keeler et al, 1991;Liu et al, 1996 ) in the Beijing, Shanghai, Lanzhou, and Guangzhou samples, respectively. On average, a large fraction (59%) of aerosol acidity was released as in-situ acidity (228 nmol m −3 ) due to the high levels of aerosol water content in the Beijing samples.…”

Section: Characteristics Of Acidity Sulfate and Ammoniummentioning

confidence: 93%

Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

2009

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Abstract. Strong atmospheric photochemistry in summer can produce a significant amount of secondary aerosols, which may have a large impact on regional air quality and visibility. In the study reported herein, we analyzed sulfate, nitrate, and ammonium in PM 2.5 samples collected using a 24-h filter system at suburban and rural sites near four major cities in China (Beijing, Shanghai, Guangzhou, and Lanzhou). Overall, the PM 2.5 mass concentrations were high (with a mean value of 55-68 g µgm −3 ), which reflects the long-known particulate pollution in China's large urban centers. We observed very high concentrations of sulfate and nitrate at the Beijing and Shanghai sites, and, in particular, abnormally high levels of nitrate (24-h average concentration up to 42gµgm −3 and contributing up to 25% of the PM 2.5 mass) in the ammonium-poor samples. The Beijing and Shanghai aerosols were characterized by high levels of aerosol acidity (∼220-390 nmol m −3 ) and low levels of insitu pH (−0.77 to −0.52). In these samples, the formation of the observed high concentrations of particulate nitrate cannot be explained by homogeneous gas-phase reaction between ammonia and nitric acid. Examination of the relation of nitrate to relative humidity and aerosol loading suggests that the nitrate was most probably formed via the heterogeneous hydrolysis of N 2 O 5 on the surface of the moist and acidic aerosols in Beijing and Shanghai. In comparison, the samples collected in Lanzhou and Guangzhou were ammoniumrich with low levels of aerosol acidity (∼65-70 nmol m −3 ), and the formation of ammonium nitrate via the homogeneous gas-phase reaction was favored, which is similar to many previous studies. An empirical fit has been derived to relate fine nitrate to aerosol acidity, aerosol water content, aerosol surface area, and the precursor of nitrate for the data from Beijing and Shanghai.

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Section: Characteristics Of Acidity Sulfate and Ammoniummentioning

confidence: 93%

Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

2009

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“…[12] Acidic and basic aerosols and gases were sampled using a dual annular denuder and dual filter method [Keeler et al, 1991] (EPA method IO-4.2), which were extracted and analyzed by ion chromatography on a Dionex DX-600 system. The first denuder was coated with sodium carbonate to collect the gases SO 2 , HNO 3 , HONO, HCl, and HBr.…”

Section: Methodsmentioning

confidence: 99%

The effects of the coastal environment on the atmospheric mercury cycle

2003

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[1] Atmospheric mercury (Hg) species were investigated on the east coast of Florida during June 2000. The site was impacted by air mass transport from the Atlantic Ocean and south Florida. Periods with atmospheric transport from the Atlantic were characterized by low concentrations of elemental gaseous Hg and inorganic divalent reactive gaseous mercury (RGM), demonstrating that the marine boundary layer was not a significant source of RGM to this coastal site as previous researchers have hypothesized. When anthropogenic impacts were observed at the site, indicated by elevated concentrations of gases including HNO 3 and SO 2 , RGM concentrations had higher daytime maximums. Particulate phase Hg concentrations were higher than can be explained by sea spray alone, as determined by chemical analysis of the seawater, suggesting that gaseous Hg is diffusing into the sea-salt aerosol. Although atmospheric Hg concentrations were not elevated, the observed scavenging of Hg gases by sea-salt aerosols indicates that Hg may be rapidly cycled at the atmosphere-ocean interface between gaseous, aerosol, and oceanic forms. Deposition of aerosol enriched in Hg via this process may constitute a significant global mercury flux to the oceans.

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“…Fine particulate matter with an aerodynamic diameter >2.1 pm (PM2.1) was sampled using a glass impactor/filter pack system. Fine particle strong acidity, fine particle sulfate, and gaseous acids (nitrous and nitric acids) were sampled using the Harvard EPA Annular Denuder System (HEADS) in 21 communities (19)(20)(21). In three communities with expected low levels of gas-phase acidity, the Harvard Impactors with ammonia denuders were used.…”

Section: Methodsmentioning

confidence: 99%

Health effects of acid aerosols on North American children: respiratory symptoms.

Dockery

Cunningham

Damokosh

et al. 1996

Environ Health Perspect

264

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We examined the respiratory health effects of exposure to acidic air pollution among 13,369 white children 8 to 12 years old from 24 communities in the United States and Canada between 1988 and 1991. Each child's parent or guardian completed a questionnaire. Air quality and meteorology were measured in each community for a 1-year period. We used a two-stage logistic regression model to analyze the data, adjusting for the potential confounding effects of sex, history of allergies, parental asthma, parental education, and current smoking in the home. Children living in the community with the highest levels of particle strong acidity were significantly more likely [odds ratio (OR) = 1.66; 95% confidence interval (CI) 1.11-2.48] to report at least one episode of bronchitis in the past year compared to children living in the least-polluted community. Fine particulate sulfate was also associated with higher reporting of bronchitis (OR = 1.65; 95% CI 1.12-2.42). No other respiratory symptoms were significantly higher in association with any of the air pollutants of interest. No sensitive subgroups were identified. Reported bronchitis, but neither asthma, wheeze, cough, nor phlegm, were associated with levels of particle strong acidity for these children living in a nonurban environment. Images Figure 1. Figure 2. Figure 3.

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Acid aerosol measurements at a suburban Connecticut site

Cited by 41 publications

References 25 publications

Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

The effects of the coastal environment on the atmospheric mercury cycle

Health effects of acid aerosols on North American children: respiratory symptoms.

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Acid aerosol measurements at a suburban Connecticut site

Cited by 41 publications

References 25 publications

Summertime PM&lt;sub&gt;2.5&lt;/sub&gt; ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

Summertime PM&lt;sub&gt;2.5&lt;/sub&gt; ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

The effects of the coastal environment on the atmospheric mercury cycle

Health effects of acid aerosols on North American children: respiratory symptoms.

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Product

Resources

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Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere

Summertime PM<sub>2.5</sub> ionic species in four major cities of China: nitrate formation in an ammonia-deficient atmosphere