Pollution In California Research Articles

Source apportionment of Volatile Organic Compounds (VOCs) in the South Coast Air Basin (SoCAB) During RECAP-CA

Ozone (O3) concentrations in the South Coast Air Basin (SoCAB) surrounding Los Angeles remain at unhealthy levels despite multiple decades of control programs designed to reduce emissions of precursor Volatile Organic Compounds (VOCs). Here we report on comprehensive VOC measurements made at Redlands, which has the highest measured O3 concentrations in SoCAB, as part of the Re-Evaluating the Chemistry of Air Pollutants in California (RECAP-CA) field campaign (July–October 2021). Positive matrix factorization (PMF) analysis was applied to identify nine VOC factors. A photochemical chamber model initialized by field measurements was configured with a tagging technique to quantify the VOC factor contributions to O3 formation in Redlands. Biogenic VOCs (BVOCs) made the largest contribution (26.6%) to O3 formation, followed by traffic VOCs (21.2%), volatile chemical products (VCPs) (19%), and plant decomposition (14.9%). High O3 episodes were not driven by increased VOC emissions from any single source, but rather were associated with stagnation events that concentrated VOCs from all sources and high temperature days that enhanced O3 formation efficiency. This implies that VOC controls optimized to reduce O3 concentrations would look similar in both the NOx-limited and VOC-limited regimes that can occur at Redlands. These results suggest that control strategies that reduce VOC and NOx emissions from the on-road vehicle fleet, such as increasing electrification, may yield O3 reductions on days in both the NOx-limited and VOC-limited chemical regimes at Redlands.

A better representation of VOC chemistry in WRF-Chem and its impact on ozone over Los Angeles.

The declining trend in vehicle emissions has underscored the growing significance of Volatile Organic Compound (VOC) emissions from Volatile Chemical Products (VCP). However, accurately representing VOC chemistry in simplified chemical mechanisms remains challenging due to its chemical complexity including speciation and reactivity. Previous studies have predominantly focused on VOCs from fossil fuel sources, leading to an underrepresentation of VOC chemistry from VCP sources. We developed an integrated chemical mechanism, RACM2B-VCP, that is compatible with WRF-Chem and is aimed to enhance the representation of VOC chemistry, particularly from VCP sources, within the present urban environment. Evaluation against the Air Quality System (AQS) network data demonstrates that our model configured with RACM2B-VCP reproduces both the magnitude and spatial variability of O3 as well as PM2.5 in Los Angeles. Furthermore, evaluation against comprehensive measurements of O3 and PM2.5 precursors from the Reevaluating the Chemistry of Air Pollutants in California (RECAP-CA) airborne campaign and the Southwest Urban NO x and VOC Experiment (SUNVEx) ground site and mobile laboratory campaign, confirm the model's accuracy in representing NOx and many VOCs and highlight remaining biases. Although there exists an underprediction in the total VOC reactivity of observed VOC species, our model with RACM2B-VCP exhibits good agreement for VOC markers emitted from different sectors, including biogenic, fossil fuel, and VCP sources. Through sensitivity analyses, we probe the contributions of VCP and fossil fuel emissions to total VOC reactivity and O3. Our results reveal that 52% of the VOC reactivity and 35% of the local enhancement of MDA8 O3 arise from anthropogenic VOC emissions in Los Angeles. Significantly, over 50% of this anthropogenic fraction of either VOC reactivity or O3 is attributed to VCP emissions. The RACM2B-VCP mechanism created, described, and evaluated in this work is ideally suited for accurately representing ozone for the right reasons in the present urban environment where mobile, biogenic, and VCP VOCs are all important contributors to ozone formation.

Costs of Air Pollution in California's San Joaquin Valley: A Societal Perspective of the Burden of Asthma on Emergency Departments and Inpatient Care.

The San Joaquin Valley (SJV) is often recognized as one of the most polluted regions in the US. Periods of pollution exposure are associated with increased health burden related to respiratory inflammation and undermined lung function, which aggravates respiratory diseases such as asthma and leads to symptoms such as coughing, wheezing, or difficulty breathing. Asthma costs US$ 82 billion annually in healthcare costs, missed work and school in the US. Employing a societal perspective, a cost of illness design was combined with environmental epidemiological methods to analyze the economic impact of O3, NO2, and PM2.5-related adverse respiratory health outcomes amongst SJV residents who attended the emergency department (ED) or were hospitalized in 2016. Asthma exacerbations monetized value ranged from US$ 3353 to US$ 5003 per ED visit and for hospital admissions US$ 2584 per inpatient day for adults 65 years and older to US$ 3023 per child. The estimated value to society in healthcare costs, productivity losses, school absences, and opportunity costs from air pollution adverse health outcomes totaled US$ 498,014,124 in ED visits and US$ 223,552,720 in hospital admissions for the SJV population in 2016. The marginal reduction in the background concentrations of pollutants would avert 21,786 ED adverse events and 19,328 hospitalizations from the health burden on the SJV population or US$ 8,024,505 cost savings due to O3, US$ 82,482,683 from NO2 reductions, and US$ 46,214,702 from decreased concentration of PM2.5. This study provides evidence that air pollution is a negative externality that imposes substantial social, environmental, and healthcare costs on the SJV. Furthermore, the region would avert significant adverse health outcomes realizing economic savings by reducing air pollution and exposures.

Analysis of gasoline-related pollutant exposures and risks in California between 1996 and 2014

BackgroundGasoline-powered vehicles and equipment are an important source of air pollution in California. Many gasoline-related pollutants pose significant health concerns. The California Air Resources Board strictly regulates the state’s gasoline formulation and vehicle emissions.ObjectiveTo investigate exposure trends for gasoline-related air pollutants between 1996 and 2014, capturing the period before and after the removal of methyl t-butyl ether (MTBE).MethodsWe identified gasoline-related chemicals with known or suspected health concerns and adequate ambient air monitoring data. Average exposures to the general public were estimated from 1996 to 2014 in five major air basins and statewide. We determined the fractions of exposures attributable to gasoline use and evaluated cancer and non-cancer risks for chemicals with available cancer potencies and health reference values.ResultsWe found that average gasoline-attributable cancer risks for the general California population from the most highly emitted carcinogens (acetaldehyde, benzene, 1,3-butadiene, and formaldehyde) declined by over 80% between 1996 and 2014. This decline occurred despite roughly constant statewide gasoline sales, an increase in vehicle miles traveled, and an approximately 10% increase in vehicle registrations over this same period. Naphthalene, measured as a volatile organic compound (VOC), was the most abundant gasoline-related polycyclic aromatic hydrocarbon (PAH). From 1996 to 2014, gasoline-attributable cancer risks for naphthalene were estimated to drop approximately threefold in the South Coast Air Basin. Exposures to gasoline-related chemicals associated with non-cancer health effects, such as chronic respiratory toxicity or neurotoxicity, were generally below levels of concern. The exception was acrolein, with gasoline-related exposures in 2014 estimated to be high enough to pose risks for respiratory toxicity.Impact statementOur historical analysis demonstrated the success of California’s regulatory efforts to reduce gasoline-related air pollutant exposures and risks to the general public. New efforts are focused on addressing gasoline-related and other air pollution in heavily impacted communities affected by multiple environmental and social stressors.

Improved Spatial Resolution in Modeling of Nitrogen Oxide Concentrations in the Los Angeles Basin.

The extent to which emission control technologies and policies have reduced anthropogenic NOx emissions from motor vehicles is large but uncertain. We evaluate a fuel-based emission inventory for southern California during the June 2021 period, coinciding with the Re-Evaluating the Chemistry of Air Pollutants in CAlifornia (RECAP-CA) field campaign. A modified version of the Fuel-based Inventory of Vehicle Emissions (FIVE) is presented, incorporating 1.3 km resolution gridding and a new light-/medium-duty diesel vehicle category. NOx concentrations and weekday-weekend differences were predicted using the WRF-Chem model and evaluated using satellite and aircraft observations. Model performance was similar on weekdays and weekends, indicating appropriate day-of-week scaling of NOx emissions and a reasonable distribution of emissions by sector. Large observed weekend decreases in NOx are mainly due to changes in on-road vehicle emissions. The inventory presented in this study suggests that on-road vehicles were responsible for 55-72% of the NOx emissions in the South Coast Air Basin, compared to the corresponding fraction (43%) in the planning inventory from the South Coast Air Quality Management District. This fuel-based inventory suggests on-road NOx emissions that are 1.5 ± 0.4, 2.8 ± 0.6, and 1.3 ± 0.7 times the reference EMFAC model estimates for on-road gasoline, light- and medium-duty diesel, and heavy-duty diesel, respectively.

Measurement report: Airborne measurements of NOx fluxes over Los Angeles during the RECAP-CA 2021 campaign

Abstract. Nitrogen oxides (NOx≡NO+NO2) are involved in most atmospheric photochemistry, including the formation of tropospheric ozone (O3). While various methods exist to accurately measure NOx concentrations, it is still a challenge to quantify the source and flux of NOx emissions. We present airborne measurements of NOx and winds used to infer the emission of NOx across Los Angeles. The measurements were obtained during the research aircraft campaign RECAP-CA (Re-Evaluating the Chemistry of Air Pollutants in CAlifornia) in June 2021. Geographic allocations of the fluxes are compared to the NOx emission inventory from the California Air Resources Board (CARB). We find that the NOx fluxes have a pronounced weekend effect and are highest in the eastern part of the San Bernardino Valley. The comparison of the RECAP-CA and the modeled CARB NOx fluxes suggests that the modeled emissions are higher than expected near the coast and in Downtown Los Angeles and lower than expected further inland in the eastern part of the San Bernardino Valley.

Pollution control bonds and environmental performance in energy utility firms: is there an incantation effect?

PurposeThis study aims to examine the effects of green financing through pollution control bonds (PCBs) on environmental performance.Design/methodology/approachThis study is based on a panel of 189 US energy utility firms observed over the period, 2011–2021 ; this study applies Generalized Method of Moments regressions.FindingsThis study found that PCBs positively affect environmental performance (aggregate measure, greenhouse emissions, waste landfill, waste incineration and waste recycling). These findings remain robust when this study considers alternative measures of PCBs and environmental performance, the quantile regression method and some firms’ attributes such as financial performance and firm age.Practical implicationsThe results indicate that US energy utility firms have to adopt more PCBs. This study helps researchers, practitioners, shareholders, bondholders, equity analysts and local authorities such as the California Pollution Control Financing Authority, municipalities and investors understand PCBs issuance, usefulness and relevance.Originality/valueTo the best of the authors’ knowledge, this study is the first to explore the effectiveness of PCBs in reducing pollution.

Direct observations of NOxemissions over the San Joaquin Valley using airborne flux measurements during RECAP-CA 2021 field campaign

Abstract. Nitrogen oxides (NOx) are principle components of air pollution and serve as important ozone precursors. As the San Joaquin Valley (SJV) experiences some of the worst air quality in the United States, reducing NOx emissions is a pressing need, yet quantifying current emissions is complicated due to a mixture of mobile and agriculture sources. We performed airborne eddy covariance flux measurements during the Re-Evaluating the Chemistry of Air Pollutants in California (RECAP-CA) field campaign in June 2021. Combining footprint calculations and land cover statistics, we disaggregate the observed fluxes into component fluxes characterized by three different land cover types. On average, we find emissions of 0.95 mg N m−2 h−1 over highways, 0.43 mg N m−2 h−1 over urban areas, and 0.30 mg N m−2 h−1 over croplands. The calculated NOx emissions using flux observations are utilized to evaluate anthropogenic emissions inventories and soil NOx emissions schemes. We show that two anthropogenic inventories for mobile sources, EMFAC (EMission FACtors) and FIVE (Fuel-based Inventory for Vehicle Emissions), yield strong agreement with emissions derived from measured fluxes over urban regions. Three soil NOx schemes, including the MEGAN v3 (Model of Emissions of Gases and Aerosols from Nature), BEIS v3.14 (Biogenic Emission Inventory System), and BDISNP (Berkeley–Dalhousie–Iowa Soil NO Parameterization), show substantial underestimates over the study domain. Compared to the cultivated soil NOx emissions derived from measured fluxes, MEGAN and BEIS are lower by more than 1 order of magnitude, and BDISNP is lower by a factor of 2.2. Despite the low bias, observed soil NOx emissions and BDISNP present a similar spatial pattern and temperature dependence. We conclude that soil NOx is a key feature of the NOx emissions in the SJV and that a biogeochemical-process-based model of these emissions is needed to simulate emissions for modeling air quality in the region.

The local impacts of coal and oil power plant retirements on air pollution and cardiorespiratory health in California: An application of generalized synthetic control method

BackgroundThis study capitalized on coal and oil facility retirements to quantify their potential effects on fine particulate matter (PM2.5) concentrations and cardiorespiratory hospitalizations in affected areas using a generalized synthetic control method. MethodsWe identified 11 coal and oil facilities in California that retired between 2006 and 2013. We classified zip code tabulation areas (ZCTA) as exposed or unexposed to a facility retirement using emissions information, distance, and a dispersion model. We calculated weekly ZCTA-specific PM2.5 concentrations based on previously estimated daily time-series PM2.5 concentrations from an ensemble model, and weekly cardiorespiratory hospitalization rates based on hospitalization data collected by the California Department of Health Care Access and Information. We estimated the average differences in weekly average PM2.5 concentrations and cardiorespiratory hospitalization rates in four weeks after each facility retirement between the exposed ZCTAs and the synthetic control using all unexposed ZCTAs (i.e., the average treatment effect among the treated [ATT]) and pooled ATTs using meta-analysis. We conducted sensitivity analyses to consider different classification schemes to distinguish exposed from unexposed ZCTAs, including aggregating outcomes with different time intervals and including a subset of facilities with reported retirement date confirmed via emission record. ResultsThe pooled ATTs were 0.02 μg/m3 (95% confidence interval (CI): −0.25 to 0.29 μg/m3) and 0.34 per 10,000 person-weeks (95%CI: −0.08 to 0.75 per 10,000 person-weeks) following the facility closure for weekly PM2.5 and cardiorespiratory hospitalization rates, respectively. Our inferences remained the same after conducting sensitivity analyses. ConclusionsWe demonstrated a novel approach to study the potential benefits associated with industrial facility retirements. The declining contribution of industrial emissions to ambient air pollution in California may explain our null findings. We encourage future research to replicate this work in regions with different industrial activities.

Ambient temperature and air pollution associations with suicide and homicide mortality in California: A statewide case-crossover study

BackgroundHigher ambient temperature and air pollution may contribute to increased risk of behaviors harmful to oneself or to others; however, quantitative evidence is limited. We examined the relationship of deaths due to suicide and homicide with temperature and air pollution in California—a state prone to high levels of both exposures. MethodCalifornia death certificates from 2014 to 2019 were used to identify deaths due to suicide and homicide. Residential data for decedents were used to assign exposure to daily temperature (maximum[Tmax], minimum[Tmin]) and daily average air pollution concentrations (particulate matter <10 μm[PM10] and < 2.5 μm[PM2.5], nitrogen dioxide[NO2], ozone[O3]). Tmin served as a surrogate for nighttime temperature. A time-stratified case-crossover study design using conditional logistic regression was used to assess the effects of daily exposure to temperature and air pollutants on suicide and homicide mortality, adjusting for relative humidity. Effect modification by sex and age was assessed. ResultsWe observed 24,387 deaths due to suicide and 10,767 deaths due to homicide. We found a monotonic temperature association for both outcomes. A 5 °C increase in Tmax at lag-2 and Tmin at lag-0 was associated with 3.1 % (95 % confidence interval [CI]: 1.1 %–5.2 %) and 3.8 % (95%CI: 0.9 %–6.8 %) increased odds of death due to suicide, respectively. The increased odds of homicide mortality per 5 °C increase in Tmax at lag-0 and Tmin at lag-1 were 4.9 % (95%CI: 1.6 %–8.1 %) and 6.2 % (95%CI: 1.6 %–11.0 %), respectively. No air pollutant associations were statistically significant. Temperature associations were robust after adjustment for PM2.5. Some temperature effects were larger among women for suicide and men for homicide mortality, and among those over age 65 years for both outcomes. ConclusionRisk of suicide and homicide mortality increases with increasing daily ambient temperatures. Findings have public health relevance given anticipated increases in temperatures due to global climate change.

Chemical ionization mass spectrometry utilizing ammonium ions (NH4+ CIMS) for measurements of organic compounds in the atmosphere

Abstract. We describe the characterization and field deployment of chemical ionization mass spectrometry (CIMS) using a recently developed focusing ion-molecule reactor (FIMR) and ammonium–water cluster (NH4+⋅H2O) as the reagent ion (denoted as NH4+ CIMS). We show that NH4+⋅H2O is a highly versatile reagent ion for measurements of a wide range of oxygenated organic compounds. The major product ion is the cluster with NH4+ produced via ligand-switching reactions. Other product ions (e.g., protonated ion, cluster ion with NH4+⋅H2O, with H3O+, and with H3O+⋅H2O) are also produced, but with minor fractions for most of the oxygenated compounds studied here. The instrument sensitivities (ion counts per second per part per billion by volume, cps ppbv−1) and product distributions are strongly dependent on the instrument operating conditions, including the ratio of ammonia (NH3) and H2O flows and the drift voltages, which should be carefully selected to ensure NH4+⋅H2O as the predominant reagent ion and to optimize sensitivities. For monofunctional analytes, the NH4+⋅H2O chemistry exhibits high sensitivity (i.e., &gt;1000 cps ppbv−1) to ketones, moderate sensitivity (i.e., between 100 and 1000 cps ppbv−1) to aldehydes, alcohols, organic acids, and monoterpenes, low sensitivity (i.e., between 10 and 100 cps ppbv−1) to isoprene and C1 and C2 organics, and negligible sensitivity (i.e., &lt;10 cps ppbv−1) to reduced aromatics. The instrumental sensitivities of analytes depend on the binding energy of the analyte–NH4+ cluster, which can be estimated using voltage scanning. This offers the possibility to constrain the sensitivity of analytes for which no calibration standards exist. This instrument was deployed in the RECAP campaign (Re-Evaluating the Chemistry of Air Pollutants in California) in Pasadena, California, during summer 2021. Measurement comparisons against co-located mass spectrometers show that the NH4+ CIMS is capable of detecting compounds from a wide range of chemical classes. The NH4+ CIMS is valuable for quantification of oxygenated volatile organic compounds (VOCs) and is complementary to existing chemical ionization schemes.

The impact of coal and oil power plants retirements on air pollution and cardiorespiratory health in California: an application of generalized synthetic control design

Background and Aim: Evidence documenting the harmful consequences of ambient air pollution can be advanced by examining the effect of well-defined interventions on air pollution and possible benefits on health outcomes. This study aims to evaluate the effect of coal and oil facility retirements, on fine particulate matter (PM2.5) and cardiorespiratory hospitalizations in California. Methods: We identified 15 coal and oil facilities in California that retired between January 1st, 2006 and December 31st, 2013 and estimated the effect of facility retirements with a generalized synthetic control design. We classified California zip codes as exposed or unexposed to a facility retirement using emissions information and a dispersion model. We then estimated the difference in weekly average PM2.5 concentrations and cardiorespiratory hospitalization rate after each facility retirement between the exposed zip codes and the synthetic control generated based on all unexposed zip codes (i.e., the average treatment effect among the exposed [ATE]). Time-fixed (e.g., age distribution) confounding are controlled by study design while time-varying confounders like temperature were adjusted for in the model. We pooled ATEs across facilities using meta-regressions. Results: The generalized synthetic control performed well with overlapping trends pre-retirement between the exposed zip codes and synthetic controls. The pooled ATE was 0.02 µg/m3 (95% confidence interval (CI): -0.25 to 0.29 µg/m3) for weekly PM2.5. The pooled ATE across all facility retirements was 0.34 per 10,000 person-time (95% CI: -0.08 to 0.75 per 10,000 person-time) for weekly cardiorespiratory hospitalization rates. Conclusions: We did not identify reductions in PM2.5 or cardiorespiratory hospitalization rates after oil and coal facility closures in California. The declining contribution of industrial emissions to ambient air pollution in California may explain this observation. We encourage future research to replicate this work in regions with different amounts of industrial activity. KeyWords: Quasi-experimental, natural experiment, air pollution, industrial facility

Population co-exposure to extreme heat and wildfire smoke pollution in California during 2020

Excessive warming from climate change has increased the total wildfire burned area over the past several decades in California. This has increased population exposure to both hazardous concentrations of air pollutants from fires such as fine particulate matter (smoke PM2.5) and extreme heat events. Exposure to PM2.5 and extreme heat are individually associated with negative health impacts and recent epidemiological evidence points to synergistic effects from concurrent exposures. This study characterizes the frequency and spatial distribution of co-occurring extreme heat and smoke PM2.5 events in California during the record-setting wildfire season of 2020. We measure exceedances over extreme thresholds of modeled surface-level smoke PM2.5 concentrations and heat index based on observed temperature and humidity. We estimate that, during the studied period, extreme smoke and heat co-occurred at least once within 68% of the state’s area (∼288 000 km2) and an average 2.5 times across all affected areas. Additionally, 16.5 million people, mostly in lower population density areas, were impacted at least once in 2020 by such synergistic events. Our findings suggest that public health guidance and adaptation policies should account for co-exposures, not only distinct exposures, when confronting heat and smoke PM2.5.

Responses of Photochemical Air Pollution in California's San Joaquin Valley to Spatially and Temporally Resolved Changes in Precursor Emissions.

Ground-level ozone adversely affects human health and ecosystems. The effectiveness of control programs depends on which precursor(s) are controlled, by how much, and where and when emission reductions occur. We use the adjoint of the Community Multiscale Air Quality model to investigate odd oxygen (Ox ≡ O3 + NO2) sensitivities in California's San Joaquin Valley (SJV) to precursor emissions from local and upwind sources. Sensitivities are mapped and disaggregated by hour and day. Taken together, impacts of precursor emissions in the San Francisco Bay area and Sacramento Valley are similar in magnitude to impacts of local SJV emissions. Same-day emission sensitivities are mostly attributable to local sources, with the most influential anthropogenic emissions of VOCs (volatile organic compounds) and NOx (nitrogen oxides) occurring in the morning (9-11 am) and early afternoon hours (1-3 pm), respectively. For the northernmost SJV receptor, the influence from Sacramento Valley emissions peaks 5-6 h later than Bay area emissions; this difference diminishes for SJV receptors located further downwind. Results show a shift toward more NOx-sensitive conditions in the afternoon with all but the southernmost receptor shifting from VOC- to NOx-sensitive conditions. We also evaluate opportunities to control pollution through shifts in precursor emission location and timing.

Future emissions of particles and gases that cause regional air pollution in California under different greenhouse gas mitigation strategies

Mitigating future climate change and managing future air quality are inter-related fields that have the potential to benefit from coordinated strategies that leverage the efforts in one area to achieve positive outcomes in the other area. California plans to reduce greenhouse gas (GHG) emission by 80% (relative to year 1990) by the year 2050. The changes required to meet this target also have the potential to improve air quality. Previous work developed an energy-economic model CA-TIMES and an emission inventory model CA-REMARQUE to study the possible pathways of meeting the GHG mitigation target and the air pollutant emissions associated with those pathways. Here we update the CA-TIMES and CA-REMARQUE model framework and analyze six different scenarios: (i) BAU - a business-as-usual future reference scenario, (ii) CAP30 - a loose GHG reduction scenario that meets current policy references but only achieves a 40% GHG reduction (relative to 1990 levels) by the year 2030, (iii) GHGAi - a climate-friendly 80% GHG reduction scenario featuring broad adoption of advanced technologies and renewable energies, (iv) CCS - a scenario that achieves 80% net GHG reductions but allows for more fossil energy combustion by focusing on adoption of carbon capture and sequestration technology, (v) NGB– a variation on the GHGAi scenario that allows for more natural gas combustion for residential and commercial buildings, and (vi) NGT – a variation of the GHGAi scenario that allows for more natural gas combustion for electricity generation. Results show that the GHGAi deep GHG mitigation scenario significantly reduces emissions (−41% PM0.1, −8% PM2.5, and −26% NOX) and improves air quality (−1 μg m−3 PM2.5) yielding public health benefits (+USD 20B yr−1) relative to the BAU scenario. The CCS scenario achieves the same GHG reductions but increases emissions in some areas (+2.5% PM2.5) resulting in only one third of the public health benefits compared to the GHGAi scenario. The NGB and NGT scenarios show that an 18% increase in natural gas utilization in buildings or a 15% increase in natural gas power generation offsets 32% and 46% of the ultrafine particle emission reduction achieved in the GHGAi scenario but has little impact on PM2.5 concentrations, producing approximately 90% of the public health benefits of the GHGAi scenario. These public health benefits should be considered when making decisions about future GHG mitigation strategies.

Institutional Drivers of Planning for Cascading Disaster Risks: The Case of Wildfire-Induced Air Pollution in California

Institutional Drivers of Planning for Cascading Disaster Risks: The Case of Wildfire-Induced Air Pollution in California

Upstream oil and gas production and ambient air pollution in California

BackgroundPrior studies have found that residential proximity to upstream oil and gas production is associated with increased risk of adverse health outcomes. Emissions of ambient air pollutants from oil and gas wells in the preproduction and production stages have been proposed as conferring risk of adverse health effects, but the extent of air pollutant emissions and resulting nearby pollution concentrations from wells is not clear. ObjectivesWe examined the effects of upstream oil and gas preproduction (count of drilling sites) and production (total volume of oil and gas) activities on concentrations of five ambient air pollutants in California. MethodsWe obtained data on approximately 1 million daily observations from 314 monitors in the EPA Air Quality System, 2006-2019, including daily concentrations of five routinely monitored ambient air pollutants: PM2.5, CO, NO2, O3, and VOCs. We obtained data on preproduction and production operations from Enverus and the California Geographic Energy Management Division (CalGEM) for all wells in the state. For each monitor and each day, we assessed exposure to upwind preproduction wells and total oil and gas production volume within 10 km. We used a panel regression approach in the analysis and fit adjusted fixed effects linear regression models for each pollutant, controlling for geographic, seasonal, temporal, and meteorological factors. ResultsWe observed higher concentrations of PM2.5 and CO at monitors within 3 km of preproduction wells, NO2 at monitors at 1-2 km, and O3 at 2-4 km from the wells. Monitors with proximity to increased production volume observed higher concentrations of PM2.5, NO2, and VOCs within 1 km and higher O3 concentrations at 1-2 km. Results were robust to sensitivity analyses. ConclusionAdjusting for geographic, meteorological, seasonal, and time-trending factors, we observed higher concentrations of ambient air pollutants at air quality monitors in proximity to preproduction wells within 4 km and producing wells within 2 km.

How has California’s Shelter-in-Place Order due to COVID-19 and the Resulting Reduction in Human Activity Affected Air and Water Quality?

As the world continues to battle the novel coronavirus or COVID-19, many states in the USA have restricted outdoor human activity, intending to reduce the number of viral infections. In turn, the number of cars on the streets and factories in operation has decreased. This unique time for the world has created an opportunity to study the impacts of reduced human activity. We collected water and air quality data through field data collection and remote data sites to test how the change in human activity affected the concentration of pollutants in water and air. Throughout California, we studied three test sites in June and July from 2015 to 2020 to compare the collected field or monitored water and air quality data over the past five years. We hypothesized that with the reduction of human activity, and therefore car emissions, the air and water pollutants in all three test locations would decrease for June/July 2020 compared to the last five years. In our study, the air quality improved from 2015 to 2020 in terms of the oxides of nitrogen (NOx) and ozone (O3), especially at Lake Tahoe’s Placer County. However, the water quality remained relatively constant for the test sites over the course of the study, while it significantly improved Sonoma County’s Russian River. Overall, the air pollution in California for June and July somewhat decreased from 2015 to 2020, while the water quality remained fairly constant in June and July during California’s shelter-in-place order.

Mental Health Outcomes Associated with Air Pollutants in California

Background: Epidemiologic studies of air pollution and mental health are limited. We examined ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), and fine particles (PM2.5), and emergency room (ER) visits from all mental disorders, bipolar disorder, depression, schizophrenia, substance abuse, homicide/inflicted injury, and suicide/self-harm. We also evaluated effect modification by season, age, race/ethnicity, and gender.Methods: Air pollutant data, provided by the US EPA, and ER visit data from the California Office of Statewide Health and Development Planning, were merged from 2005 through 2013. Data analyses were conducted using two-stage quasi-Poisson regression models, adjusting for long-term trends, holidays, day of the week, and mean apparent temperature. Several lag periods were considered (same day up to average of 7 days and average of 30 days).Results: Per interquartile range, weekly mean O3 was associated with a 1.87% (95% confidence interval [CI]: 0.62, 3.15) increase in ER visits for depression (n = 162,451), a 1.43% (0.35, 2.51) increase for suicide/self-harm (n = 198,509), and a 2.83% (1.53, 4.15) increase for bipolar disorder (n = 158,906). O3 (30 day lag; n = 632, 787), CO (2 day lag; n = 229,138) and NO2 (2-day lag; n = 206,919) were associated with greater risks for homicides/self-inflicted injury (2.01% [1.01, 3.02]; 2.3% [1.3, 3.3]; and 2.6% [1.2, 4.0], respectively). Greater risk was found during the warm season for CO and NO2. For some outcomes, differential risk was observed by gender, age, and race/ethnicity. These associations generally remained robust in co-pollutant models. No associations were found between PM2.5 and any of the mental health outcomes considered.Conclusions: Our results suggest that short-term gaseous air pollution exposure increases the risk of homicides/inflicted injury (CO, NO2 and O3), and depression, suicide/self harm, and bipolar disorder (latter three outcomes for O3 only) in California.

Wildfire and COVID-19 pandemic: effect of environmental pollution PM-2.5 and carbon monoxide on the dynamics of daily cases and deaths due to SARS-COV-2 infection in San-Francisco USA.

The wildfire allied environmental pollution is highly toxic and can cause significant wide-ranging damage to the regional environment, weather conditions, and it can facilitate the transmission of microorganisms and diseases. The present study aims to investigate the effect of wildfire allied pollutants, particulate matter (PM-2.5 μm), and carbon monoxide (CO) on the dynamics of daily cases and deaths due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection in San Francisco, USA. For this study, we selected San Francisco, one of the regions affected by the wildfires allied pollution in California, USA. The data on the COVID-19 pandemic in San Francisco, including daily new cases and new deaths were recorded from Worldometer Web. The daily environmental pollutants particulate matter (PM-2.5 μm) and carbon monoxide (CO) were recorded from the metrological web "BAAQMD". The daily cases, deaths, particulate matter (PM-2.5 μm) and carbon monoxide were documented from the date of the occurrence of the first case of (SARS-CoV-2) in San Francisco, CA, USA, from March 20, 2020 to Sept 16, 2020. The results revealed a significant positive correlation between the environmental pollutants particulate matter (PM2.5 μm) and the number of daily cases (r=0.203, p=0.007), cumulative cases (r=0.567, p<0.001) and cumulative deaths (r=0.562, p<0.001); whereas the PM2.5 μm and daily deaths had no relationship (r=-0.015, p=0.842). In addition, CO was also positively correlated with cumulative cases (r=0.423, p<0.001) and cumulative deaths (r=0.315, p<0.001), however, CO had no correlation with the number of daily cases (r=0.134, p=0.075) and daily deaths (r=0.030, p=0.693). In San Francisco, one micrometer (μg/m3) increase in PM2.5 caused an increase in the daily cases, cumulative cases and cumulative deaths of SARS-COV-2 by 0.5%, 0.9% and 0.6%, respectively. Moreover, with a 1 part per million(ppm) increase in carbon monoxide level, the daily number of cases, cumulative cases and cumulative deaths increased by 5%, 9.3% and 5.3%, respectively. On the other hand, CO and daily deaths had no significant relationship. The wildfire allied pollutants, particulate matter PM-2.5μm and CO have a positive association with an increased number of SARS-COV-2 daily cases, cumulative cases and cumulative deaths in San Francisco. The metrological, disaster management and health officials must implement the necessary policies and assist in planning to minimize the wildfire incidences, environmental pollution and COVID-19 pandemic both at regional and international levels.