Theo. J. Kneip

Airborne Particulates in New York City

This study was undertaken to identify seasonal and source effects on the par-ticulate contaminants of the New York City atmosphere and ultimately to relate the concentrations of these contaminants to the tissue concentrations in residents of New York City. Continual weekly samples of particulates have been collected at three stations in the New York area on 8 by 10 in. glass fiber filters at a flow rate of 20 cfm. The sample is ashed with a Tracerlab Low Temperature Asher and leached with nitric acid. Metals analyzed by the Atomic Absorption method include Pb, V, Cd, Cr, Cu, Mn, Ni, and Zn. Lead-210, total particulate, and benzene and acetone soluble organic material are also determined. The data have been related to various meteorological parameters over a one year period to define significant seasonal and source influences, as well as site to site variations. Very significant inverse correlations to temperature are obtained for suspended particulates, vanadium, and nickel at both Manhattan and Bronx sit...

Ambient levels of particulate organic matter in New York City in winter and summer

Abstract Samples of suspended particulate matter were collected during two summer and two winter sampling campaigns. Non-polar, moderately polar and polar fractions of particulate organic matter (POM) were separated by 8h sequential Soxhlet extractions with cyclobexane, dichloromethane and acetone, respectively. Atmospheric concentrations of total POM averaged 13.0 μgm −3 for the two summer periods and 16.0 μgm −3 for the two winter periods. Extractable organic matter in respirable (D 50 ≤3.5 μm aerodynamic diameter) suspended particulate matter was 81% of the TSP organics during January–February 1978, but only 54% of TSP organics in August 1978. Evaluation of dispersion normalized aerosol concentrations of POM indicated that space heating contributed approximately 75% of the total POM in New York City in February 1977 and 51% in January–February 1978. The strong association of POM with the “oil-burning” factor obtained by factor analysis performed on the data was also indicative of a substantial contribution from this source. Use of high-sulfur (1.5–15 %) fuel oil in New York City during the 1976–1977 fuel crisis appears to have had a striking and significant impact on both total emissions and ambient concentrations of POM during February 1977. The cumulative evidence indicates oil-burning for space heating is currently the most significant source of POM although it contributes only 10–20% of the TSP. The atmospheric concentrations of POM and TSP determined in this study were compared to those measured at the same site in 1968 and 1969. Although wintertime TSP levels have declined to almost one-half of the levels of 1968 and 1969, wintertime concentrations of airborne POM do not appear to have declined. The summertime concentrations of POM in 1977 and 1978 were about 40% higher than those determined for similar periods in 1968 and 1969.

An investigation of interurban variations in the chemical composition and mutagenic activity of airborne particulate organic matter using an integrated chemical class/bioassay system

Abstract Previous investigations in this laboratory have demonstrated that the mutagenic activities of extractable particulate organic matter (EOM) from cities which differ in their principal fuels and meteorology can vary significantly. To gain a better understanding of these interurban variations, an Integrated Chemical Class/Biological Screening System was developed and used for a more detailed examination of differences in the chemical composition and mutagenic activity of EOM. The screening system involved coupling in situ Ames mutagenicity determinations on high performance thin layer chromatography (HPTLC) plates with class specific chemical analyses on a second set of plates. The system was used to screen for mutagenic activity and selected chemical classes (including PAH, nitro-PAH, phenols, carboxylic acids, carbonyls, aza-arenes and alkylating agents) in EOM from the following sites: New York City; Elizabeth, N.J.; Mexico City; Beijing, China; Philadelphia, PA; and the Caldecott Tunnel (CA). The results of this study demonstrated mutagenic activity and chemical compositional differences in HPTLC subfractions of particulate organic matter from these cities and from the Caldecott Tunnel. The greatest interurban differences in chemical classes were observed for the phenols, carbonyl compounds and alkylating agents. Interurban variations in mutagenic activities were greatest for EOM subfractions of intermediate polarity. These differences are probably related to interurban differences in the fuels used, types of sources and atmospheric conditions. The relationships between these variables are not well understood at present.

The measurement of H2SO4 and other sulfate species at Tuxedo, New York with a thermal analysis flame photometric detector and simultaneously collected quartz filter samples

A study of major atmospheric particulate sulfate species was conducted during 30 July 1980–1983 September 1980 in Sterling Forest, a rural area in Tuxedo, NY, not affected by major local sources of pollution. In situ measurements of total sulfate, sulfuric acid and ammonium sulfate ammonium bisulfate were made using Thermal Analysis-Flame Photometric Detection (TA-FPD). These measurements were compared to the total sulfate and strong acid (H+) concentration measured in simultaneously collected 12 h, treated quartz filter samples. The concentration of NH4HSO4 was inferred from the difference between the total strong acid concentration and the sulfuric acid measurements, so that total sulfate and acid concentrations could be balanced. A major sulfate pollution episode occurred during the period of 27–29 August. The concentration of H+ showed an excess above that necessary to account for the TA-FPD H2SO4 measurement, indicating the presence of NH4 HSO4. The maximum 12 h average concentrations of H2SO4, NH4HSO4 and (NH4)2SO4 were 5.18, 11.42 and 10.08 μg m−3 as SO42− respectively, and were measured from 9:15 to 21:15 on 28 August. The study demonstrated the usefulness of concurrent measurements of airborne particulate sulfate by filter extraction and TA-FPD to identify acidic sulfate species.

Long-Term Trends in Total Suspended Participates, Vanadium, Manganese, and Lead at near Street Level and Elevated Sites in New York City

Long-term concentration measurements of TSP, V, Pb, and Mn have been made in New York City. Three month moving averages have been constructed from integrated weekly data collected at the NYU Medical Center rooftop site from 1968-78. Rooftop vs. 1st floor concentration comparisons have been made at two locations for the periods 1968-70 and 1976-78. TSP, V, Pb and Mn have decreased in ambient concentration over the entire study. This reflects the controls incorporated on sources over the 10 yr period. The rooftop vs. 1st floor analyses have shown the influence of source distribution on concentration patterns. V levels showed no difference between the rooftop and 1st floor concentrations, which demonstrates the elevated nature of the sources and uniform mixing of material in the atmosphere. Pb, Mn, TSP, showed higher values at the ground, which would be indicative of ground level sources. During 1978, Mn and Pb increased throughout all (Pb) or part (Mn) of the year. The concentrations of these materials do n...

Source apportionment of carbonaceous aerosol in New York City by multiple linear regression

A multiple linear regression model was applied to aerosol chemical data from New York City to determine the sources of carbonaceous aerosol. The model used elemental tracers for auto exhaust aerosol (Pb), residual oil combustion (V), resuspended dust (Mn or Fe), and incineration (Cu or Zn). Although relative uncertainties in the source apportionment were greater than 20%, auto exhaust was found to be the main source of organic carbon with lesser contributions from other sources. A substantial fraction of elemental carbon could not be associated with the sources used in the model and was possibly associated with the combustion of diesel and distillate oils. The regression coefficients, which are related to source composition, compared well with actual measured source compositions. Because of the uncertainties it was concluded that source apportionment, especially as it relates to the development of control strategies, should utilize the results of several receptor and source models where possible. 12 references.

Seasonal patterns of airborne particulate concentrations in New York City

Abstract Total suspended particulate (TSP) measurements of the New York City atmosphere have in the past failed to exhibit meaningful seasonal patterns, despite the fact that there are known seasonal differences in the strengths of sources contributing to the TSP. It has been found that when the TSP measurements are normalized for the effects of wind speed and the height of the atmosphere mixing layer, pronounced seasonal differences are seen. Based on analysis of two years of data, it is seen that emissions are increased during the winter months, presumably by combustion of oil for space heating. This source evidently contributes an average of 40 per cent of the total suspended particulates during the winter and ca . 20–30 per cent of the annual average total suspended particulate.

The impact of changing air quality on multiple regression models for coarse and fine particle fractions

Abstract Increases were noted in the concentrations of total suspended paniculate matter and several metals in New York City air in late 1968. This shift in the air quality persisted until late 1980. We have found that the change in air quality affects the multiple regression technique for apportioning sources of the suspended particulate matter. Separate regression models are required for coarse and fine particles. The shift appears related mainly to increased coarse particle emissions possibly related to changing sources of residual oil for use in boilers used for heating systems.

Trace Metal Concentration Factors in Aquatic Ecosystems

The concept of concentration factors in aquatic systems is of ultimate importance in assessing the impact of any contaminant on such an ecosystem. While the general concept of bioconcentration is widely used, it is readily apparent that the qualifying assumptions and detailed theory underlying the concept often are not considered, leading to widespread misuse and misunderstanding of the phenomenon.

The effects of number of samples and random error on the factor analysis/multiple regression (FA/MR) receptor modeling technique

Abstract The effects of normally distributed random errors and of sample size on the stability of FA/MR results were examined as applied to a data set from the ATEOS studies. Three levels of normally distributed random errors were added to the original data set to produce five perturbed data sets for FA testing and a total of 10 for testing the MR results. Reductions of sample size from 138 cases to 70 and 35 cases (24-h daily samples) were performed both randomly and systematically. The addition of random errors reduced squared multiple correlation coefficients to the same extent for different sample sizes. The effect of a reduction in sample had a more significant impact on the standard errors of regression coefficients than did added random errors of up to ± 30% of the measured independent variables. Reducing the data sets to 70 and 35 cases resulted in nonsignificant coefficients for a variable whose t-value was relatively small in the data set with 138 cases. This analysis demonstrated the usefulness of the degrees of freedom criteria suggested by Henry (1984, Atmospheric Environment18, 1507–1515) for minimum sample size in multivariate analysis. The results also showed that data sets with smaller sample sizes tend to give larger R2s than the data sets with larger samples sizes, due to their fewer degrees of freedom. It is recommended that the relative significance of parameters that can contribute to the variance of the data set be investigated.