2002-2017 anthropogenic emissions data for air quality modeling over the United States

The United States Environmental Protection Agency (US EPA) has developed a set of annual North American emissions data for multiple air pollutants across 18 broad source categories for 2002 through 2017. The sixteen new annual emissions inventories were developed using consistent input data and methods across all years. When a consistent method or tool was not available for a source category, emissions were estimated by scaling data from the EPA's 2017 National Emissions Inventory with scaling factors based on activity data and/or emissions control information. The emissions datasets are designed to support regional air quality modeling for a wide variety of human health and ecological applications. The data were developed to support simulations of the EPA's Community Multiscale Air Quality model but can also be used by other regional scale air quality models. The emissions data are one component of EPA's Air Quality Time Series Project which also includes air quality modeling inputs (meteorology, initial conditions, boundary conditions) and outputs (e.g., ozone, PM_2.5 and constituent species, wet and dry deposition) for the Conterminous US at a 12 km horizontal grid spacing.

Evaluation of 15 years of modeled atmospheric oxidized nitrogen compounds across the contiguous United States

Atmospheric nitrogen oxide and nitrogen dioxide (NO + NO2, together termed as NO X ) estimates from annual photochemical simulations for years 2002-2016 are compared to surface network measurements of NO X and total gas-phase-oxidized reactive nitrogen (NO Y ) to evaluate the Community Multiscale Air Quality (CMAQ) modeling system performance by U.S. region, season, and time of day. In addition, aircraft measurements from 2011 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality are used to evaluate how emissions, chemical mechanism, and measurement uncertainty each contribute to the overall model performance. We show distinct seasonal and time-of-day patterns in NO X performance. Summertime NO X is overpredicted with bimodal peaks in bias during early morning and evening hours and persisting overnight. The summertime morning NO X bias dropped from between 28% and 57% for earlier years (2002-2012) to between -2% and 7% for later years (2013-2016). Summer daytime NO X tends to be unbiased or underpredicted. In winter, the evening NO X overpredictions remain, but NO X is unbiased or underpredicted overnight, in the morning, and during the day. NO X overpredictions are most pronounced in the Midwestern and Southern United States with Western regions having more of a tendency toward model underpredictions of NO X . Modeled NO X performance has improved substantially over time, reflecting updates to the emission inputs and the CMAQ air quality model. Model performance improvements are largest for years simulated with CMAQv5.1 or later and for emission inventory years 2014 and later, coinciding with reduced onroad NO X emissions from vehicles with newer emission control technologies and improved treatment of chemistry, deposition, and vertical mixing in CMAQ. Our findings suggest that emissions temporalization of specific mobile source sectors have a small impact on model performance, while chemistry updates improve predictions of NO Y but do not improve summertime NO X bias in the Baltimore/DC area. Sensitivity runs performed for different locations across the country suggest that the improvement in summer NO X performance can be attributed to updates in vertical mixing incorporated in CMAQv5.1.

Reflecting on progress since the 2005 NARSTO emissions inventory report

Emission inventories are the foundation for cost-effective air quality management activities. In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American emissions inventories and made recommendations for improving their effectiveness. This paper reviews the recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. The findings reveal that all emissions inventory improvement areas identified by the 2005 NARSTO publication have been explored and implemented to some degree. The U.S. National Emissions Inventory has become more detailed and has incorporated new research into previously under-characterized sources such as fine particles and biomass burning. Additionally, it is now easier to access the emissions inventory and the documentation of the inventory via the internet. However, many emissions-related research needs exist, on topics such as emission estimation methods, speciation, scalable emission factor development, incorporation of new emission measurement techniques, estimation of uncertainty, top-down verification, and analysis of uncharacterized sources. A common theme throughout this retrospective summary is the need for increased coordination among stakeholders. Researchers and inventory developers must work together to ensure that planned emissions research and new findings can be used to update the emissions inventory. To continue to address emissions inventory challenges, industry, the scientific community, and government agencies need to continue to leverage resources and collaborate as often as possible. As evidenced by the progress noted, continued investment in and coordination of emissions inventory activities will provide dividends to air quality management programs across the country, continent, and world. Implications: In 2005, a report by the public/private partnership North American Research Strategy for Tropospheric Ozone (NARSTO) evaluated the strengths and weaknesses of North American air pollution emissions inventories. This paper reviews the eight recommendation areas and briefly discusses what has been addressed, what remains unchanged, and new questions that have arisen. Although progress has been made, many opportunities exist for the scientific agencies, industry, and government agencies to leverage resources and collaborate to continue improving emissions inventories.

Residential status and HIV risk behaviors among Puerto Rican drug injectors in New York and Puerto Rico

This article investigates the association between residential status and human immunodeficiency virus (HIV) risk behaviors among island and New York Puerto Rican injection drug users (IDUs). We assigned 561 subjects from New York City and 312 from Puerto Rico to five residential status categories: living in parent's home, living in own home, living in other's home, living in temporary housing (hotel, single-room occupancy [SRO] hotels), and homeless (living in streets/shelters). Dependent variables included injection- and sex-related risk behaviors (sharing syringes, sharing other injection paraphernalia, shooting gallery use, and having paid sex). Chi square, t tests, and multivariate logistic analysis tests were performed separately by site. About one-quarter of the sample in each site was homeless. Island Puerto Ricans were more likely to live with their parents (44% vs. 12%, p < .001), and more New York IDUs lived in their own home (30% vs. 14%, p < .001). In New York, gallery use and paid sex were associated with living in other's home, living in parent's home, and being homeless. Sharing paraphernalia was related to living in other's home, living in temporary housing, and being homeless. In Puerto Rico, having paid sex was associated with homelessness. High-risk behaviors were more likely among homeless IDUs in both sites. Programs to provide housing and target outreach and other prevention programs for homeless IDUs would be helpful in reducing HIV risk.

An alternative program for methadone maintenance dropouts: description and preliminary data

Time in drug treatment has been shown to be one of the best predictors of post-treatment success. Since as many as half of the enrollees leave methadone treatment during the first year, the project described in this article was designed to test the effectiveness of an alternative program for individuals who have recently dropped out of methadone maintenance treatment. The goals of this "Alternative Program" are to help participants re-connect with formal drug treatment and other community or medical programs, reduce their HIV risk behavior, decrease or eliminate drug use, join self-help groups, and obtain entitlements. Program components include: contacts by local outreach workers, cognitive-behavioral relapse-prevention group counseling, and individual counseling for needs assessment and referral. This paper describes the basis for development of the intervention, summarizes the methodology being used, and provides preliminary data on participation in the Alternative Program.

Cessation of drug use: impact of time in treatment

Many studies have found that the longer a drug user remains in treatment, the more positive the outcome. The majority of studies on the effects of time in treatment have followed subjects from the time they enter treatment. The subjects of the present study are injection drug users and crack users who were out of treatment at the time of their recruitment to the study. Between the initial and six-month follow-up interviews, some chose to enroll in drug treatment. The more time a subject spent in treatment during the follow-up period, the more likely it was that s/he was not using heroin or cocaine at follow-up (OR=.51; 95% C.I., .39-.67; p<.001). Unlike the results of some prior studies, positive effects of time in treatment were found even when time in treatment was less than 90 days. The findings of the present study strongly suggest that treatment is beneficial even for those who remain for less than 90 days. Those who provide treatment services to drug users should attempt to maintain contact with dropouts, and support their return to treatment.

HIV infection and patterns of risk among women drug injectors and crack users in low and high sero-prevalence sites

As AIDS cases among US women continue to increase, a better understanding of women's behavioural risk patterns is needed to inform intervention efforts. Data were from 2,945 women drug injectors and crack users. Statistical analyses compared sociodemographic variables, lifetime behavioural risk patterns, HIV sero-prevalence and history of sexually transmitted diseases, and determined predictors of HIV infection separately in 16 low and four high sero-prevalence sites. Based on risk patterns, four behaviourally-defined sub-groups were constructed, and rates of HIV sero-prevalence were compared. In comparisons between low and high sero-prevalence sites, there were significant differences on most variables examined, and in the relative importance of the sociodemographic characteristics and risk patterns predicting HIV. Drug injection and sex exchange were each independent, significant, behavioural predictors of infection, with no significant difference between the odds ratios attributed to each predictor. HIV sero-prevalence was significantly different among four sub-groups. Interventions must be tailored to address observed differences among women in low and high sero-prevalence sites. Injection drug use and exchanging sex each play a major role in the transmission of HIV infection to US women. Prevention efforts targeted at women should address differences in behavioural risk patterns. Aggressive and innovative interventions are needed for women who exchange sex. AIDS research must investigate how socioeconomic factors impact women's risk for HIV infection.

Agreement between urinalysis and self-reported drug use

One hundred fifty-eight drug users received an interview that included self-reported drug use. Opiate/cocaine use in the prior 48 hours was assessed by urinalysis. Fifty-five subjects received a urine test after the interview and 103 were tested before. Chi-square tests were performed to determine if agreement between self-reported drug use and urine test results was associated with timing of urine testing. The rate of agreement was 58% when the urine test was performed after the interview and 93% when performed before the interview (chi2 = 28.6, p < .001). Conducting urine tests before an interview can increase the accuracy of self-reports.

Predictors of change in frequency of crack cocaine use in a street-recruited sample

Crack cocaine users are at high risk for HIV, with higher frequency crack users engaging in higher rates of HIV-related sexual risk behaviors. This study will assess the variables impacting changes in crack use frequency. Out-of-treatment crack users were street recruited in East Harlem, NY. Subjects (n = 727) were 33% female, 91% minority, and 28% reported recent drug injecting. Baseline and 6-month follow-up interviews were administered. There was a significant reduction in crack use over time (p < .0001). Subjects were categorized according to five groups, based on their change in level of crack use between the two interviews, to predict those who stopped, maintained, or changed their level of use. Discriminant analyses identified six variables as the best predictors of the five groups, including having been in drug treatment since baseline and having been a drug injector (both related to reduced levels of crack use). The overall reduction in crack use for the sample masked the fact that important subgroups remained at high use levels or increased their use. The identification of subgroups who may be most resistant to reducing drug use can be helpful in developing more effective interventions.

Trends in injection risk behaviors in a sample of New York City injection drug users: 1992-1995

OBJECTIVES

This study assessed the relation between year of recruitment into an AIDS prevention project and likelihood of engaging (yes/no) in injection risk behaviors.

METHODS

In total, 834 injection drug users were recruited over a 44-month period (January 1992-August 1995) in New York City. Logistic regression was used to examine trends in three behaviors, across four successive annual cohorts: using needles/syringes that were previously used by another person, using injection supplies (e.g., cookers, cotton, rinse water) that had been previously used, and giving or lending of used needles/syringes to another person.

RESULTS

Significant (p < .0001) decreasing trends occurred in two behaviors: giving or lending of used needles/syringes to another person and use of injection supplies that had been used by another person. Sample characteristics were generally consistent over time and did not obviate significant injection risk trends.

CONCLUSIONS

Decreasing trends in injection risk behaviors could not be explained by changing sample characteristics. Even though some injectors report engaging in risky injection practices, the confluence of numerous AIDS prevention efforts in the 1990s has contributed to an overall reduction in the likelihood of such behaviors.

Declining seroprevalence in a very large HIV epidemic: injecting drug users in New York City, 1991 to 1996

OBJECTIVES

This study assessed recent trends in HIV seroprevalence among injecting drug users in New York City.

METHODS

We analyzed temporal trends in HIV seroprevalence from 1991 through 1996 in 5 studies of injecting drug users recruited from a detoxification program, a methadone maintenance program, research storefronts in the Lower East Side and Harlem areas, and a citywide network of sexually transmitted disease clinics. A total of 11,334 serum samples were tested.

RESULTS

From 1991 through 1996, HIV seroprevalence declined substantially among subjects in all 5 studies: from 53% to 36% in the detoxification program, from 45% to 29% in the methadone program, from 44% to 22% at the Lower East Side storefront, from 48% to 21% at the Harlem storefront, and from 30% to 21% in the sexually transmitted disease clinics (all P < .002 by chi 2 tests for trend).

CONCLUSIONS

The reductions in HIV seroprevalence seen among injecting drug users in New York City from 1991 through 1996 indicate a new phase in this large HIV epidemic. Potential explanatory factors include the loss of HIV-seropositive individuals through disability and death and lower rates of risk behavior leading to low HIV incidence.

HIV serostatus and risk behaviors in a multisite sample of drug users

In developing HIV prevention efforts, it is critical to determine whether interventions are effective in achieving declines in risk behavior among both HIV-positive and HIV-negative individuals. Based on a multisite intervention study of injection drug users (IDUs) and crack smokers, 488 seropositive IDUs and 364 seropositive crack users were compared with randomly selected matched samples of seronegatives (with matching based on recruitment site, gender, age group and ethnicity) at baseline and six-month follow-up to compare changes in risk behaviors by serostatus. Results indicated that overall, risk behaviors declined substantially over time; significant interaction effects indicated that seropositives reported a greater decline in sex risk behaviors than seronegatives. These data support the utility of HIV testing for high-risk drug users, and indicate that interventions have produced reductions in risk behaviors of both seropositives and seronegatives. Further research on the impact of site seroprevalence, and to enhance our understanding of those who continue to engage in risky behaviors, is needed.

Urban crack users: gender differences in drug use, HIV risk and health status

This study assessed gender differences in drug use, HIV risk, and health status in a sample of urban crack users. Using targeted sampling, 1434 crack users (66% male and primarily African-American and Puerto Rican), were recruited from the streets of East Harlem, New York City. A standardized, structured interview was administered, drug use was validated by urinalysis, and HIV testing was offered. Gender differences were observed on sociodemographic variables and patterns of drug use. Other than welfare, men and women cited different major sources of income. Women reported greater use of crack, and men were more likely to use injection drugs as well as crack. Data on sexual risk indicated that women had more sexual partners than men, but the percentage of unprotected vaginal sex for both men and women was greater for those who did not exchange sex for drugs and/or money. The number of persons already infected with HIV was substantial. Many reported histories of other sexually transmitted diseases which were generally higher among men. Future research should investigate the relationship between gender and other factors (e.g., ethnicity, geographic location) associated with HIV risk.

Predictors of HIV infection among women drug users in New York and Miami

In the US, the number of women diagnosed with AIDS continues to increase. In this study, women in New York City (East Harlem) and Miami, two sites with high rates of drug use and HIV infection, were first compared on sociodemographic variables and risk behaviors. Logistic regression analyses were used to identify significant, independent predictors of HIV infection in each city. In comparing women from the two cities, several differences in sociodemographic characteristics and drug use were observed. In both cities, ever exchanging sex for drugs and/or money was predictive of HIV infection; and in East Harlem only, other lifetime risk variables independently predicted HIV infection: drug injection, having a sexually transmitted disease, and not having graduated from high school. Results suggest that intervention efforts with women who exchange sex should be intensified in both cities. Also, further comparisons of women drug users in AIDS epicenter cities are necessary to provide information on similarities and differences in sociodemographic characteristics and individual risk behaviors. More research attention should be focused on examining the social context of HIV risk in order to develop innovative intervention strategies which focus on the link between contextual factors and HIV infection.

Crack users in east Harlem, New York and Philadelphia, Pennsylvania: HIV-related risk behaviors and predictors of serostatus

Crack use has been associated with increased risk for HIV seropositivity. This study was undertaken to examine HIV-related risk behaviors among crack users in East Harlem, New York and Philadelphia, Pennsylvania, two northeastern communities which have reported extensive crack use. Crack users recruited in East Harlem (n = 1434) and Philadelphia (n = 694) were compared on demographics, drug and sex-related risk behaviors, health-related behaviors, and HIV serostatus. Many significant differences were found, and seropositivity was higher in the New York sample (25% vs. 11%, chi 2 = 36.28, p < .001). Being a recent drug injector was a significant predictors of seropositivity in both communities, and differences between communities were found in additional predictors of serostatus. Results suggest that tailored HIV interventions may be needed for different communities. In addition, aggregate data across communities, even those that may be in geographical proximity, may obfuscate differences important to incorporate in developing prevention/intervention efforts.

Gender differences and other factors associated with HIV testing in a national sample of active drug injectors

Gender, health, HIV risk, and demographic factors were examined with chi-square and logistic regression analyses to assess which of these factors are most predictive of active injection drug users' (IDUs') getting tested for HIV. Analyses were based on 36,898 IDUs recruited to participate in a nationwide multisite HIV prevention project. Women IDUs were recently tested (prior 6 months) more than men IDUs. Health factors, particularly for women IDUs, predicted who got tested for HIV more than risk or demographic factors. HIV testing usually occurred when disease symptomatology developed, after a long period of being capable of transmitting HIV to others, and when the benefits of AZT and other interventions may be reduced. Preventive interventions with IDUs are needed that emphasize the possible benefits of HIV testing and that encourage testing before symptoms develop.

HIV risk behaviors among Dominican brothel and street prostitutes in New York City

Latina women are overrepresented among AIDS cases in the United States. To assist in developing appropriate prevention and intervention programs, information regarding HIV risk behaviors is needed on the many diverse Latina subgroups. This study examined sociodemographic characteristics and HIV risk behaviors of Dominican female prostitutes, comparing those who worked primarily in brothels with those who were street workers. A total of 77 Dominican prostitutes (54 brothel; 23 street) were recruited in New York City to participate in a structured interview and were offered HIV testing. Ethnographic interviews were conducted with a subscale. Results indicated that there were many significant differences in demographics and risk behaviors between the two groups, and those working in brothels engaged in lower levels of risk behaviors. In addition, those working in brothels had closer ties to the Dominican and Spanish cultures. Implications for AIDS prevention efforts are discussed.

HIV-related concerns and behaviors among Hispanic women

Hispanic women whose sexual partners have other sexual partners may be at risk for HIV. A structured interview was administered to 106 Dominican and Puerto Rican women who reported that they knew or suspected that their partner had other partners. A subsample participated in qualitative interviews. The study assessed concern about HIV and predictors of condom use. The majority of women reported that they worried about getting HIV and almost half had been HIV-tested. Most of the women discussed HIV/AIDS concerns with their partners, and one-third reported some condom use. Predictors of condom use were: born in the Dominican Republic/Puerto Rico, having talked with their partner about being tested, and belief that he used condoms with others. Although the women were concerned about HIV, condom use was infrequent. Results suggested methods to address this discrepancy: introducing condoms early in the relationship, developing women-controlled methods, and directly influencing men's behavior.

Outcomes of a risk-reduction intervention with high-risk populations: the Harlem AIDS project

Many studies of interventions with high-risk populations have reported reductions in risk behaviors. To assess effectiveness of interventions, data are also needed on the characteristics of subjects lost to follow-up, and on follow-up risk behaviors for subjects who were not participants in the intervention. This paper reports on a study conducted in Harlem, New York, recruiting 1,770 injection drug users (IDUs) and sex partners of IDUs, randomly assigned to two interventions. Repeated-measures analyses for the two intervention groups and those who participated in no intervention indicated that all groups reported significant reductions in risk behaviors, with no group effect. Comparisons of those followed-up and not followed-up indicate that those followed-up were less likely to: be homeless, be Latinos, and to use "shooting galleries." The discussion focuses on the need to assess outcomes for all types of participants, and to distinguish the impact of interventions from other explanations for behavior changes.

The risk of HIV infection in a national sample of women with injection drug-using partners

OBJECTIVES

This study reports on a large, national cohort of women with injection drug-using sex partners. Information is provided on demographic characteristics; human immunodeficiency virus (HIV) risk factors, including unprotected sex and incidence of sexually transmitted diseases; use of noninjected drugs; HIV serostatus; and other selected health variables.

METHODS

A sample of 5162 heterosexual women was recruited for a national acquired immunodeficiency syndrome (AIDS) research and demonstration project. A structured interview was administered, and the women had the option of undergoing HIV testing. Statistical analyses compared three groups on variables of interest: women with single sex partners, women with multiple partners, and women with multiple partners who exchanged sex for drugs and/or money.

RESULTS

These groups differed significantly on virtually all of the demographic and risk variables examined. Women with multiple partners who exchanged sex for drugs and/or money were at higher risk for HIV than women in the other groups, even when selected demographic variables were controlled.

CONCLUSIONS

Research is needed on the efficacy of prevention efforts involving these diverse groups of women at risk for AIDS.

HIV risk factors among pregnant and non-pregnant high-risk women in New York City

A comparison of high-risk pregnant (n = 55) and non-pregnant (n = 598) women from Harlem, New York City on HIV-related drug and sexual risk behaviors was undertaken to identify appropriate prevention and intervention policy recommendations. Clients were recruited for an AIDS risk reduction research demonstration project and were either intravenous drug users (IVDUs) or sexual partners of IVDUs. There was a higher percentage of IVDUs among the non-pregnant women, and no significant differences were found between pregnant and non-pregnant IVDUs in terms of needle risk behaviors. The two groups were also similar in non-injected drug use behaviors. Pregnant women were significantly less likely to use condoms. Recommendations focused on the need for increased HIV risk reduction among high-risk women in general, and increased education efforts among pregnant high-risk women regarding condom use as protection from HIV and the potential consequences of maternal substance use for their children.