Physics-Informed Deep Learning to Reduce the Bias in Joint Prediction of Nitrogen Oxides

Atmospheric nitrogen oxides (NOx) primarily from fuel combustion have recognized acute and chronic health and environmental effects. Machine learning (ML) methods have significantly enhanced our capacity to predict NOx concentrations at ground-level with high spatiotemporal resolution but may suffer from high estimation bias since they lack physical and chemical knowledge about air pollution dynamics. Chemical transport models (CTMs) leverage this knowledge; however, accurate predictions of ground-level concentrations typically necessitate extensive post-calibration. Here, we present a physics-informed deep learning framework that encodes advection-diffusion mechanisms and fluid dynamics constraints to jointly predict NO2 and NOx and reduce ML model bias by 21-42%. Our approach captures fine-scale transport of NO2 and NOx, generates robust spatial extrapolation, and provides explicit uncertainty estimation. The framework fuses knowledge-driven physicochemical principles of CTMs with the predictive power of ML for air quality exposure, health, and policy applications. Our approach offers significant improvements over purely data-driven ML methods and has unprecedented bias reduction in joint NO2 and NOx prediction

Long-term exposure to traffic-related air pollution and stroke: a systematic review and meta-analysis

Background Stroke remains the second cause of death worldwide. The mechanisms underlying the adverse association of exposure to traffic-related air pollution (TRAP) with overall cardiovascular disease may also apply to stroke. Our objective was to systematically evaluate the epidemiological evidence regarding the associations of long-term exposure to TRAP with stroke. Methods PubMed and LUDOK electronic databases were searched systematically for observational epidemiological studies from 1980 through 2019 on long-term exposure to TRAP and stroke with an update in January 2022. TRAP was defined according to a comprehensive protocol based on pollutant and exposure assessment methods or proximity metrics. Study selection, data extraction, risk of bias (RoB) and confidence assessments were conducted according to standardized protocols. We performed meta-analyses using random effects models; sensitivity analyses were assessed by geographic area, RoB, fatality, traffic specificity and new studies. Results Nineteen studies were included. The meta-analytic relative risks (and 95% confidence intervals) were: 1.03 (0.98-1.09) per 1 μg/m3 EC, 1.09 (0.96-1.23) per 10 μg/m3 PM10, 1.08 (0.89-1.32) per 5 μg/m3 PM2.5, 0.98 (0.92; 1.05) per 10 μg/m3 NO2 and 0.99 (0.94; 1.04) per 20 μg/m3 NOx with little to moderate heterogeneity based on 6, 5, 4, 7 and 8 studies, respectively. The confidence assessments regarding the quality of the body of evidence and separately regarding the presence of an association of TRAP with stroke considering all available evidence were rated low and moderate, respectively. Conclusion The available literature provides low to moderate evidence for an association of TRAP with stroke

Ambient air pollutants are associated with morning serum cortisol in overweight and obese Latino youth in Los Angeles

Background Hypothalamic-pituitary-adrenal (HPA)-axis dysfunction has been associated with a variety of mental health and cardio-metabolic disorders. While causal models of HPA-axis dysregulation have been largely focused on either pre-existing health conditions or psychosocial stress factors, recent evidence suggests a possible role for central nervous system activation via air pollutants, such as nitrogen dioxide (NO2), ozone (O3) and particulate matter (PM). Therefore, in an observational study of Latino youth, we investigated if monthly ambient NO2, O3, and PM with aerodynamic diameter&thinsp;&le;&thinsp;2.5 (PM2.5) exposure were associated with morning serum cortisol levels. Methods In this cross-sectional study, morning serum cortisol level was assessed after a supervised overnight fast in 203 overweight and obese Latino children and adolescents (female/male: 88/115; mean age: 11.1&thinsp;&plusmn;&thinsp;1.7&thinsp;years; pre-pubertal/pubertal/post-pubertal: 85/101/17; BMI z-score: 2.1&thinsp;&plusmn;&thinsp;0.4). Cumulative concentrations of NO2, O3 and PM2.5 were spatially interpolated at the residential addresses based on measurements from community monitors up to 12&thinsp;months prior to testing. Single and multi-pollutant linear effects models were used to test the cumulative monthly lag effects of NO2, O3, and PM2.5 on morning serum cortisol levels after adjusting for age, sex, seasonality, social position, pubertal status, and body fat percent by DEXA. Results Single and multi-pollutant models showed that higher O3 exposure (derived from maximum 8-h exposure windows) in the prior 1&ndash;7&thinsp;months was associated with higher serum morning cortisol (p&thinsp;&lt;&thinsp;0.05) and longer term PM2.5 exposure (4&ndash;10&thinsp;months) was associated with lower serum morning cortisol levels (p&thinsp;&lt;&thinsp;0.05). Stratification by pubertal status showed associations in pre-pubertal children compared to pubertal and post-pubertal children. Single, but not multi-pollutant, models showed that higher NO2 over the 4&ndash;10&thinsp;month exposure period associated with lower morning serum cortisol (p&thinsp;&lt;&thinsp;0.05). Conclusions Chronic ambient NO2, O3 and PM2.5 differentially associate with HPA-axis dysfunction, a mechanism that may serve as an explanatory pathway in the relationship between ambient air pollution and metabolic health of youth living in polluted urban environments. Further research that uncovers how ambient air pollutants may differentially contribute to HPA-axis dysfunction are warranted. </div

Racial/Ethnic Disparities in Alzheimer’s Disease Risk: Role of Exposure to Ambient Fine Particles

Background Whether racial/ethnic disparities in Alzheimer’s disease (AD) risk may be explained by ambient fine particles (PM2.5) has not been studied. Methods We conducted a prospective, population-based study on a cohort of Black (n=481) and White (n=6004) older women (aged 65-79) without dementia at enrollment (1995-98). Cox models accounting for competing risk were used to estimate the hazard ratio (HR) for racial/ethnic disparities in AD (1996-2010) defined by DSM-IV and the association with time-varying annual average PM2.5 (1999-2010) estimated by spatiotemporal model. Results Over an average follow-up of 8.3 (±3.5) years with 158 incident cases (21 in Black women), the racial disparities in AD risk (range of adjusted HRBlack women = 1.85-2.41) observed in various models could not be explained by geographic region, age, socioeconomic characteristics, lifestyle factors, cardiovascular risk factors, and hormone therapy assignment. Estimated PM2.5 exposure was higher in Black (14.38±2.21 µg/m 3) than in White (12.55±2.76 µg/m 3) women, and further adjustment for the association between PM2.5 and AD (adjusted HRPM2.5 = 1.18-1.28) slightly reduced the racial disparities by 2-6% (HRBlack women = 1.81-2.26). The observed association between PM2.5 and AD risk was ~2 times greater in Black (HRPM2.5 = 2.10-2.60) than in White (HRPM2.5 = 1.07-1.15) women (range of interaction Ps: Conclusions PM2.5 may contribute to racial/ethnic disparities in AD risk and its associated increase in AD risk was stronger amongst Black women

Prenatal exposure to ambient air pollutants and early infant growth and adiposity in the Southern California Mother's Milk Study

Background Prior epidemiological and animal work has linked in utero exposure to ambient air pollutants (AAP) with accelerated postnatal weight gain, which is predictive of increased cardiometabolic risk factors in childhood and adolescence. However, few studies have assessed changes in infant body composition or multiple pollutant exposures. Therefore, the objective of this study was to examine relationships between prenatal residential AAP exposure with infant growth and adiposity. Methods Residential exposure to AAP (particulate matter&thinsp;&lt;&thinsp;2.5 and 10 microns in aerodynamic diameter [PM2.5, PM10]; nitrogen dioxide [NO2]; ozone [O3]; oxidative capacity [Oxwt: redox-weighted oxidative potential of O3 and NO2]) was modeled by spatial interpolation of monitoring stations via an inverse distance-squared weighting (IDW2) algorithm for 123 participants from the longitudinal Mother&rsquo;s Milk Study, an ongoing cohort of Hispanic mother-infant dyads from Southern California. Outcomes included changes in infant growth (weight, length), total subcutaneous fat (TSF; calculated via infant skinfold thickness measures) and fat distribution (umbilical circumference, central to total subcutaneous fat [CTSF]) and were calculated by subtracting 1-month measures from 6-month measures. Multivariable linear regression was performed to examine relationships between prenatal AAP exposure and infant outcomes. Models adjusted for maternal age, pre-pregnancy body mass index, socioeconomic status, infant age, sex, and breastfeeding frequency. Sex interactions were tested, and effects are reported for each standard deviation increase in exposure. Results NO2 was associated with greater infant weight gain (&beta;&thinsp;=&thinsp;0.14, p&thinsp;=&thinsp;0.02) and TSF (&beta;&thinsp;=&thinsp;1.69, p&thinsp;=&thinsp;0.02). PM10 and PM2.5 were associated with change in umbilical circumference (&beta;&thinsp;=&thinsp;0.73, p&thinsp;=&thinsp;0.003) and TSF (&beta;&thinsp;=&thinsp;1.53, p&thinsp;=&thinsp;0.04), respectively. Associations of Oxwt (pinteractions&thinsp;&lt;&thinsp;0.10) with infant length change, umbilical circumference, and CTSF were modified by infant sex. Oxwt was associated with attenuated infant length change among males (&beta;&thinsp;=&thinsp;-0.60, p&thinsp;=&thinsp;0.01), but not females (&beta;&thinsp;=&thinsp;0.16, p&thinsp;=&thinsp;0.49); umbilical circumference among females (&beta;&thinsp;=&thinsp;0.92, p&thinsp;=&thinsp;0.009), but not males (&beta;&thinsp;=&thinsp;-0.00, p&thinsp;=&thinsp;0.99); and CTSF among males (&beta;&thinsp;=&thinsp;0.01, p&thinsp;=&thinsp;0.03), but not females (&beta;&thinsp;=&thinsp;0.00, p&thinsp;=&thinsp;0.51). Conclusion Prenatal AAP exposure was associated with increased weight gain and anthropometric measures from 1-to-6 months of life among Hispanic infants. Sex-specific associations suggest differential consequences of in utero oxidative stress. These results indicate that prenatal AAP exposure may alter infant growth, which has potential to increase childhood obesity risk. &nbsp;</p

Long-term exposure to traffic-related air pollution and stroke: A systematic review and meta-analysis.

BACKGROUND: Stroke remains the second cause of death worldwide. The mechanisms underlying the adverse association of exposure to traffic-related air pollution (TRAP) with overall cardiovascular disease may also apply to stroke. Our objective was to systematically evaluate the epidemiological evidence regarding the associations of long-term exposure to TRAP with stroke. METHODS: PubMed and LUDOK electronic databases were searched systematically for observational epidemiological studies from 1980 through 2019 on long-term exposure to TRAP and stroke with an update in January 2022. TRAP was defined according to a comprehensive protocol based on pollutant and exposure assessment methods or proximity metrics. Study selection, data extraction, risk of bias (RoB) and confidence assessments were conducted according to standardized protocols. We performed meta-analyses using random effects models; sensitivity analyses were assessed by geographic area, RoB, fatality, traffic specificity and new studies. RESULTS: Nineteen studies were included. The meta-analytic relative risks (and 95% confidence intervals) were: 1.03 (0.98-1.09) per 1 μg/m3 EC, 1.09 (0.96-1.23) per 10 μg/m3 PM10, 1.08 (0.89-1.32) per 5 μg/m3 PM2.5, 0.98 (0.92; 1.05) per 10 μg/m3 NO2 and 0.99 (0.94; 1.04) per 20 μg/m3 NOx with little to moderate heterogeneity based on 6, 5, 4, 7 and 8 studies, respectively. The confidence assessments regarding the quality of the body of evidence and separately regarding the presence of an association of TRAP with stroke considering all available evidence were rated low and moderate, respectively. CONCLUSION: The available literature provides low to moderate evidence for an association of TRAP with stroke

The geochemical cycling of reactive chlorine through the marine troposphere

Heterogeneous reactions involving sea‐salt aerosol in the marine troposphere are the major global source for volatile inorganic chlorine. We measured reactant and product species hypothesized to be associated with these chemical transformations as a function of phase, particle size, and altitude over the North Atlantic Ocean during the summer of 1988. Concentrations of HCl were typically less than 1.0 ppbv near the sea surface and decreased with altitude and with distance from the U.S. east coast. Concentrations of Cl volatilized from aerosols were generally equivalent to the corresponding concentrations of HCl and ranged from less than detection limits to 125 nmol m−3 STP. Highest absolute and percentage losses of particulate Cl were typically associated with elevated concentrations of anthropogenic combustion products. Concentrations of product nss SO42− and N03− in coarse aerosol fractions indicate that on average only 38% of measured Cl− deficits could be accounted for by the combined effects of acid‐base desorption and reactions involving nonacidic N gases. We hypothesize a mechanism for the Cl loss initiated by reaction of O3 at sea‐salt aerosol surfaces, generating Cl2 followed by rapid photochemical conversion of Cl2 to HCl via Cl atoms (Cl˙) and eventual recapture of HCl by the aerosol. Simulations with a zero‐dimension (0‐D) photochemical model suggest that oxidation by Cl˙ may be an important tropospheric sink for dimethyl sulfide and hydrocarbons. Under low‐NOx conditions, the rapid cycling of reactive Cl would provide a catalytic loss mechanism for O3, which would possibly explain the low O3 concentrations often observed above the world\u27s oceans

Long-term exposure to traffic-related air pollution and selected health outcomes: A systematic review and meta-analysis.

The health effects of traffic-related air pollution (TRAP) continue to be of important public health interest. Following its well-cited 2010 critical review, the Health Effects Institute (HEI) appointed a new expert Panel to systematically evaluate the epidemiological evidence regarding the associations between long-term exposure to TRAP and selected adverse health outcomes. Health outcomes were selected based on evidence of causality for general air pollution (broader than TRAP) cited in authoritative reviews, relevance for public health and policy, and resources available. The Panel used a systematic approach to search the literature, select studies for inclusion in the review, assess study quality, summarize results, and reach conclusions about the confidence in the evidence. An extensive search was conducted of literature published between January 1980 and July 2019 on selected health outcomes. A new exposure framework was developed to determine whether a study was sufficiently specific to TRAP. In total, 353 studies were included in the review. Respiratory effects in children (118 studies) and birth outcomes (86 studies) were the most commonly studied outcomes. Fewer studies investigated cardiometabolic effects (57 studies), respiratory effects in adults (50 studies), and mortality (48 studies). The findings from the systematic review, meta-analyses, and evaluation of the quality of the studies and potential biases provided an overall high or moderate-to-high level of confidence in an association between long-term exposure to TRAP and the adverse health outcomes all-cause, circulatory, ischemic heart disease and lung cancer mortality, asthma onsetin chilldren and adults, and acute lower respiratory infections in children. The evidence was considered moderate, low or very low for the other selected outcomes. In light of the large number of people exposed to TRAP - both in and beyond the near-road environment - the Panel concluded that the overall high or moderate-to-high confidence in the evidence for an association between long-term exposure to TRAP and several adverse health outcomes indicates that exposures to TRAP remain an important public health concern and deserve greater attention from the public and from policymakers